Diagnosis of Metastatic Renal Cell Carcinoma on Fine-Needle Aspiration Cytology Madelyn Lew, MD; Wen-Chi Foo, MD; Michael H. Roh, MD, PhD
Fine-needle aspiration has assumed an increasingly important role in the diagnosis and management of patients with advanced stage cancer. Given its predilection for metastases to distant sites and organs at the time of presentation, metastatic renal cell carcinoma (RCC) is not infrequently encountered in the setting of fine-needle aspiration for initial diagnosis. In some instances, fineneedle aspiration may be the only opportunity to obtain diagnostic tissue to diagnose and subclassify RCC. Therefore, cytopathologists and cytotechnologists should be familiar with and recognize the cytomorphology of RCC and the ancillary studies that can be used to confirm and subclassify RCC. Herein, we describe a case of metastatic RCC initially diagnosed on fine-needle aspiration, discuss the cytomorphologic features of RCC subtypes, and review pertinent ancillary immunohistochemical and cytogenetic adjuncts. (Arch Pathol Lab Med. 2014;138:1278–1285; doi: 10.5858/arpa.2014-0283-CC)
STUDY CASE 79-year-old man, who initially presented with progressive left-sided weakness with associated facial droop, was found on brain imaging to have a lesion in the right parietal lobe. He underwent a stereotactic biopsy of this lesion, which was nondiagnostic, as it contained only blood and fragments of unremarkable brain parenchyma. Subsequently, the patient underwent computed tomography scans of the chest, abdomen, and pelvis, which demonstrated the presence of bilateral pulmonary nodules, mediastinal and hilar lymphadenopathy, and a left renal mass. The patient did report a remote cigarette smoking history of approximately 20 pack-years. The patient was
A
Accepted for publication June 2, 2014. From the Department of Pathology (Drs Lew and Roh), University of Michigan Health System, Ann Arbor; and the Department of Pathology (Dr Foo), Duke University Medical Center, Durham, North Carolina. The authors have no relevant financial interest in the products or companies described in this article. Presented in part at the New Frontiers in Pathology: An Update for Practicing Pathologists meeting; University of Michigan; September 26–28, 2013; Ann Arbor, Michigan. Reprints: Michael H. Roh, MD, PhD, Department of Pathology, University of Michigan Health System, 2G332 UH, 1500 E Medical Center Dr, Ann Arbor, MI 48109-5054 (e-mail: [email protected]. edu). 1278 Arch Pathol Lab Med—Vol 138, October 2014
referred for endobronchial ultrasound–guided fine-needle aspiration (FNA) to investigate the underlying etiology. PATHOLOGIC FINDINGS A cytopathologist was present on site during the endobronchial ultrasound–guided FNA procedure of a 4L lymph node, during which 13 needle passes were obtained by the bronchoscopist. For each of the first 9 passes, a pair of smears was prepared: 1 air-dried smear and 1 alcohol-fixed smear. The needle was subsequently rinsed in Roswell Park Memorial Institute (RPMI) medium. Each air-dried smear was immediately Diff-Quik stained for on-site microscopic examination. The alcohol-fixed smears were set aside for Papanicolaou staining in the cytopathology laboratory to be completed after the conclusion of the procedure. Microscopic examination of the air-dried, Diff-Quik–stained smears demonstrated a hypocellular aspirate that was significant for a population of malignant-appearing epithelioid cells, arranged predominantly in sheets and small clusters (Figure 1, A). On higher magnification, marked nuclear pleomorphism, conspicuous nucleoli, and prominently vacuolated cytoplasm were appreciated; there was variability to the extent of cytoplasmic vacuolization, which ranged from fine vacuoles to large vacuoles (Figure 1, B). During the on-site evaluation, the malignant cells were identified on only 2 of the 9 Diff-Quik–stained smears; the other 7 smears consisted of predominantly blood. After the first 9 needle passes were obtained, 4 dedicated passes for the RPMI needle rinse, for the production of a cell block, were obtained. Given the cytomorphology appreciated during the on-site preliminary assessment, there was already a high index of suspicion for a metastatic renal cell carcinoma (RCC), clear cell type. After the conclusion of the FNA procedure, Papanicolaoustained smears were available for microscopic evaluation. Similar to the Diff-Quik–stained smears, the tumor cellularity on the Papanicolaou-stained smears was low overall. Nonetheless, a few clusters of malignant epithelial cells with delicate, frothy cytoplasm were appreciated (Figure 2, A and B). The cell block contained a few sheetlike clusters of tumor cells and was used for confirmatory immunohistochemistry. The tumor cells exhibited cytoplasmic immunoreactivity for CD10 and nuclear reactivity for paired box gene (PAX) 8 (Figure 2, C and D, respectively). Immunostains for cytokeratin 7 and RCC marker (RCCma) were negative (not shown). Overall, the cytomorphologic features and immunophenotype were consistent with a diagnosis of metastatic RCC, clear cell type. Metastatic Renal Cell Carcinoma on FNA—Lew et al
Figure 1. A, Examination of a stained cytologic direct smear on low magnification, during the on-site assessment, reveals the presence of neoplastic epithelial cells arranged in sheets and small clusters. B, On higher magnification, marked nuclear pleomorphism, prominent nucleoli, and overt vacuolization to the cytoplasm are evident in the tumor cells (Diff-Quik stain, original magnifications 3100 [A] and 3600 [B]).
COMMENT Fine-needle aspiration has emerged as an increasingly important modality used for the diagnosis of primary and metastatic RCCs.1,2 Confirming the diagnosis of RCC in the setting of metastatic disease enables appropriate pathologic staging, thereby facilitating appropriate clinical management.3 Although RCC represents approximately only 2% of visceral cancers, RCCs can occasionally be encountered in the setting of extrarenal FNAs, given its propensity to metastasize to distant sites.2 Previous published series specifically addressing metastatic carcinomas to various organ sites have consistently demonstrated RCC to be a common source of metastasis to extrarenal organs. For instance, RCC represents the most frequent source of metastasis encountered in lung FNAs.4 Although metastases to the pancreas are generally rare occurrences, RCC represents the most common primary etiology when metastatic tumors are encountered in the pancreas.5–10 Similarly, metastases to the thyroid gland are uncommon; nonetheless, RCC represents the most commonly encountered metastatic tumor in thyroid FNAs.11,12 Metastatic RCCs diagnosed in parotid gland FNAs have also been reported.13 As RCC may be encountered initially in the setting of metastatic disease or many years after the initial diagnosis of the primary tumor,2,8,9,11,13 it is important for cytopathologists and cytotechnologists to recognize the cytomorphologic features of RCC and its subtypes and to be familiar with ancillary studies that can aid in the diagnosis and subclassification of RCCs. Cytomorphologic Features of RCC Subtypes The cytomorphologic features of a given RCC can vary depending on its subtype as well as grade. The most common subtype of RCC is the classic or conventional (clear cell) type. As illustrated by the above case, biopsies of these lesions can be bloody and FNAs of these lesions can be very hemodilute, given the high vascularity of these tumors. These factors may result in a nondiagnostic sample. However, tumor cells, when present, are typically characArch Pathol Lab Med—Vol 138, October 2014
terized by low nuclear to cytoplasmic ratios. Nuclei can be centrally or eccentrically placed and their characteristics vary according to grade. Low-grade (Fuhrman grade 1–2) tumors have smooth to slightly irregular nuclear contours and nucleoli discernible only at high-power magnification (.3200), whereas high-grade (Fuhrman grade 3–4) tumors will have increasingly irregular nuclei, prominent nucleoli visualized at 3100, and increased pleomorphism, which may manifest as highly bizarre cells (Figure 3, A through D).14 In light of recent studies that have shown that nucleolar size alone is a more powerful prognostic parameter than any other cytologic feature in clear cell RCC, the 2012 International Society of Urological Pathology Consensus Conference recommended the use of a grading system based on nucleolar prominence alone.15,16 The cytoplasm of these tumor cells can be wispy, granular, vacuolated, or a mixture thereof.17 In high-grade tumors, the cytoplasm often takes a more coarsely granular appearance, which confers a more oncocytic appearance to the tumor. However, higher nuclear grade features typically accompany this change, which are not as commonly seen in other oncocytic renal neoplasms. The tumor cells of clear cell RCC are commonly arranged in sheets and clusters in which cell boundaries are ill defined. However, these tumor cells can present singly as well, particularly in higher-grade tumors in which there is an increased amount of cellular discohesion. The next most common subtype of RCC is the papillary type. This subtype is defined by papillary or tubulopapillary growth patterns, which compose more than 50% of the tumor.18,19 Aspirates of papillary RCC are often very cellular and consist of papillary fragments of cells. Unlike the short papillae that can occasionally be seen in clear cell RCC, the papillae in papillary RCCs are often long with complex branching architecture, easily appreciated on low magnification (Figure 4, A). Surrounding tumor cells may also be arranged in tight clusters or spherules.20,21 Papillary RCCs have a spectrum of morphologies, but have historically been subdivided into 2 main histologic subtypes, type 1 and type 2, which correlate with low- and high-grade morphologic Metastatic Renal Cell Carcinoma on FNA—Lew et al 1279
Figure 2. A and B, Cohesive sheets of tumor cells exhibiting vacuolated cytoplasm are seen. C, Immunohistochemistry performed on formalin-fixed, paraffin-embedded cell block sections reveals strong, diffuse cytoplasmic immunoreactivity for CD10 in the tumor. D, Immunohistochemistry performed on formalin-fixed, paraffin-embedded cell block sections reveal strong, diffuse nuclear immunoreactivity for PAX8 in the tumor (Papanicolaou stain, original magnifications 3400 [A and B]; original magnifications 3200 [C] and 3400 [D]).
features, respectively. In type 1 papillary RCCs, the cells are often small to medium in size and cuboidal in shape, and have uniform, round nuclei with even chromatin distribution, inconspicuous nucleoli, and scant to moderate amounts of cytoplasm. Type 2 papillary RCCs demonstrate larger cells and, similar to the cells of high-grade clear cell RCC, these cells display enlarged nuclei with prominent nucleoli and a moderate to abundant amount of granular cytoplasm.17,21,22 Given that other RCC subtypes can occasionally demonstrate a papillary-like architecture on FNA, papillary architecture with true fibrovascular cores as well as ancillary studies, discussed below, are helpful in confirming a diagnosis of papillary RCC. Another helpful morphologic feature that one can identify in FNAs of papillary RCCs is foamy macrophages within papillae as well as in the background (Figure 4, B and C). Hemosiderin deposition in tumor cells as well as macrophages is also a feature associated with papillary RCC.20,23,24 A more uncommon variant of papillary RCC is the more recently described papillary RCC with oncocytic cells.25 The cytomorphology of these tumor cells raise the differential diagnostic considerations of oncocytoma and chromophobe 1280 Arch Pathol Lab Med—Vol 138, October 2014
RCC. However, the presence of true fibrovascular cores should allow for identification of this papillary RCC variant. Next, chromophobe RCC is less common than the clear cell and papillary subtypes of RCC. Cytologic preparations are often cellular, with tumor cells arranged singly or in loosely cohesive cell groups. Key characteristics in these tumor cells include centrally placed nuclei with dark chromatin, perinuclear clearing, and abundant amounts of cytoplasm, resulting in a koilocytic appearance.26,27 Binucleation and nuclear pleomorphism are also commonly seen (Figure 5).17,28 The cytomorphologic features of chromophobe RCC can be mimicked by oncocytomas and, occasionally, eosinophilic variants of clear cell RCC. Therefore, ancillary studies, discussed below, can be used to assist in definitive classification for diagnostically challenging cases. One of the more recently described subtypes of RCC is the clear cell tubulopapillary RCC. These tumors are considered low-grade tumors and typically affect patients with endstage renal disease. Review of surgical resection specimens reveals that these tumors typically contain a mixture of cysts, papillae, tubules, acini, and solid nests of tumor cells, which Metastatic Renal Cell Carcinoma on FNA—Lew et al
Figure 3. Cytomorphology of clear cell renal cell carcinoma (RCC). A, Low-grade clear cell RCC demonstrates tumor cells in cohesive clusters. Tumor cells have abundant vacuolated to granular cytoplasm that often appears thin and wispy, with ill-defined cell membranes. B, Nuclei have relatively smooth nuclear contours and minimal cytologic atypia. Nucleoli are generally small and inconspicuous. C and D, High-grade clear cell RCCs display decreased cellular cohesion. Marked nuclear pleomorphism and prominent macronucleoli are present and the cytoplasm exhibits a more dense appearance with only fine vacuolization (Diff-Quik stain, original magnifications 3400 [A] and 3200 [C]; Papanicolaou stain, original magnifications 3400 [B and D]).
are characterized by bland nuclei, scant to moderate amounts of eosinophilic to clear cytoplasm, and reverse polarization of nuclei.29 Distinctive cytomorphologic features on smear preparations have not yet been clearly defined in the literature. However, similar to reports on surgical resection specimens, these tumor cells display nuclei with smooth nuclear contours, even chromatin, inconspicuous nucleoli, and scant to moderate amounts of finely granular to vacuolated cytoplasm (Figure 6, A). Although the smear preparations may show nonspecific findings, adequately cellular cell block preparations are helpful in displaying architectural patterns such as tubules, trabeculae, and papillary structures, as well as reverse polarization of tumor cells, that characterize these tumors (Figure 6, B). Another recently described renal tumor is the Xp11 translocation–associated RCC.30 These tumors are predominantly found in children and young adults, although there have been cases described in older patients. In surgical resection specimens, these tumors demonstrate clear cells arranged in papillary structures with dense hyaline cores. Arch Pathol Lab Med—Vol 138, October 2014
On cytology specimens, the tumor cells have eccentrically placed nuclei, irregular nuclear contours, variably prominent nucleoli, and abundant clear to granular cytoplasm, which mimics the appearance of clear cell RCC. Helpful features on smear preparations include the layering of tumor cells around dense, hyalinized central cores.31 The involvement of a younger patient and this unusual architectural arrangement of clear cells may clue a cytopathologist in to this entity. However, ancillary studies, discussed below, are usually helpful for confirming the diagnosis. Finally, sarcomatoid dedifferentiation of a RCC occurs in approximately 3% to 5% of RCCs.32,33 Cytologic preparations demonstrate a biphasic appearance that includes a high-grade epithelial component admixed with malignantappearing spindle cells. The nuclear atypia within the sarcomatoid component can vary greatly, from more uniformly spindled nuclei akin to those seen in fibrosarcomas to bizarre, pleomorphic nuclei similar to those seen in undifferentiated pleomorphic sarcomas. However, it is important to note that the relative proportions of epithelioid and sarcomatoid components depend on the sampling of Metastatic Renal Cell Carcinoma on FNA—Lew et al 1281
Figure 4. Cytomorphology of papillary renal cell carcinoma (RCC). A, In this low-magnification photomicrograph, a long, branching papillary cluster with a fibrovascular core can be appreciated. B, Foamy macrophages within the fibrovascular core and adjacent to the papillary cluster can be appreciated. C, The nuclei display minimal cytologic atypia and pleomorphism. These photomicrographs were obtained from aspirates of type 1 papillary RCC (Diff-Quik stain, original magnifications 3100 [A] and 3400 [B]; Papanicolaou stain, original magnification 3200 [C]).
Immunohistochemical Adjuncts to Assist in the Subclassification of the Common Renal Epithelial Tumors Expected Immunophenotype of Common RCC Subtypes and Oncocytoma Encountered in Cytology Marker RCC marker CD10 Vimentin CK7 PAX2 CD117/c-kit CAIX (high expression) AMACR S100A1
Clear Cell RCC þ þ þ þ þ þ
Papillary RCC
Chromophobe RCC
Oncocytoma
þ þ þ þ þ þ þ
/þ þ þ
þ þ þ
Abbreviations: AMACR, a-methylacyl coenzyme A racemase; CAIX, carbonic anhydrase IX; CD, cluster of differentiation; CK, cytokeratin; PAX2, paired box 2; RCC, renal cell carcinoma. 1282 Arch Pathol Lab Med—Vol 138, October 2014
Metastatic Renal Cell Carcinoma on FNA—Lew et al
Figure 5. Cytomorphology of chromophobe renal cell carcinoma (RCC). Aspirates of chromophobe RCC tend to be cellular samples composed of discohesive tumor cells characterized by abundant granular cytoplasm. The characteristic perinuclear clearing confers a koilocytic appearance (DiffQuik stain, original magnification 3400 [A]; Papanicolaou stain, original magnification 3400 [B]).
the tumor. Given the poor prognostic implications of sarcomatoid change in a RCC, it is important to recognize as well as mention the presence of a sarcomatoid component in diagnostic reports when encountered in cytologic samples. Immunohistochemical Adjuncts for the Identification of Metastatic RCC Traditionally, RCCma and CD10 are commonly used for the immunohistochemical confirmation of metastatic RCC. Nonetheless, there are limitations associated with the use of either marker. Although RCCma is highly specific for RCC, the use of RCCma as a confirmatory immunomarker in diagnostic cytology is limited by its relatively low sensitivity of below 60%.34,35 On the other hand, CD10 immunostaining is highly sensitive for detecting metastatic RCC but is limited by its low specificity. Specifically, in their series, Simsir and colleagues34 found that CD10 immunohistochemistry was 100% sensitive but only 59% specific for detection of metastatic RCC. Recently, members of the PAX family of transcription factors, PAX2 and PAX8, have emerged as useful immunohistochemical adjuncts for the diagnosis of metastatic RCC.35–38 Both PAX2- and PAX8-positive tumors display nuclear immunoreactivity for these markers. The sensitivity of PAX8 for detecting metastatic RCC is the highest and exceeds that of PAX2,38,39 which, in turn, exceeds the sensitivity of RCCma.36 PAX8 plays a critical role in the development of the kidney, the thyroid gland, and the female genital tract, and its expression is maintained in carcinomas derived from those sites.38–47 In their large series, Laury and colleagues48 reported that PAX8 immunoreactivity was observed in 93%, 76%, and 80% of clear cell, papillary, and chromophobe RCCs, respectively, and in virtually almost all mullerian serous carcinomas and thyroid ¨ carcinomas. Therefore, although PAX8 immunoreactivity is not exclusively observed in renal cancers, PAX8 immunohistochemistry serves as a useful diagnostic adjunct given its very high sensitivity. In the aforementioned case, the tumor cells demonstrated diffuse, strong immunoreactivity for both PAX8 and CD10, supporting of the diagnosis of metastatic RCC. Arch Pathol Lab Med—Vol 138, October 2014
Immunohistochemical and Cytogenetic Adjuncts for the Subclassification of RCC Challenges can be encountered in the subclassification of RCCs in small biopsies and FNAs. The importance of subclassification on these specimens, which may be the only opportunity to obtain diagnostic tissue, rests on prognostic and therapeutic management implications.1 Immunohistochemistry can serve as a useful adjunct to conventional cytomorphologic evaluation in the subclassification of RCCs.49 The use of panels of immunomarkers rather than a single marker alone is prudent, as the expression of any single marker is not entirely specific for a given entity. Despite variations in immunophenotypes associated with various subtypes of RCC, the expected immunophenotypes for the commonly encountered subtypes of RCC along with oncocytoma in FNA samples are summarized in the Table. The expression of RCCma, CD10, and vimentin tends to be observed mostly in clear cell and papillary RCCs; however, of the 3, the sensitivity of RCCma is the lowest.50–53 Cytokeratin 7 (CK7) is a useful marker in distinguishing papillary and chromophobe RCCs from clear cell RCCs. Clear cell RCCs tend to be CK7 negative, whereas papillary and chromophobe RCCs are usually CK7 positive.50,52 The expression of PAX2 is predominantly observed in the clear cell and the papillary RCCs; however, chromophobe RCCs usually are PAX2 negative.52,54 CD117/ c-kit expression is frequently observed in chromophobe RCCs and oncocytomas but not the clear cell or papillary subtypes of RCC.52 In this regard, S100A1 serves as a useful marker to distinguish between these two entities, as oncocytomas are typically S100A1þ, whereas chromophobe RCCs are S100A1.55 Strong, diffuse immunoreactivity for carbonic anhydrase IX and positivity for a-methylacyl coenzyme A racemase support a diagnosis of the clear cell and papillary subtypes of RCC, respectively.50,51,54,56 Next, the identification of clear cell tubulopapillary RCC can be confirmed by demonstrating immunoreactivity for CK7 (Figure 6, C) and carbonic anhydrase IX (variable), but negativity for CD10 and a-methylacyl coenzyme A racemase (Figure 6, D).29 Metastatic Renal Cell Carcinoma on FNA—Lew et al 1283
Figure 6. Cytomorphology and immunophenotypic features of clear cell tubulopapillary renal cell carcinoma (RCC). A, The cytomorphologic features of these tumors are not yet clearly defined, but tumors typically demonstrate minimal nuclear atypia and pleomorphism. B, This cellular cell block preparation highlights tubules and papillary structures lined by clear cells with reverse polarity; nuclei are aligned away from the basement membrane. C and D, Immunohistochemistry can be helpful in confirming a diagnosis of clear cell tubulopapillary RCC. Tumor cells are typically immunoreactive for cytokeratin 7 (C) and negative for a-methylacyl coenzyme A racemase (D) (Diff-Quik stain, original magnification 3400 [A]; hematoxylin-eosin, original magnification 3400 [B]; original magnifications 3400 [C and D]).
Finally, conventional cytogenetics and fluorescence in situ hybridization can be used to assist in the subclassification of RCCs.1,57 These adjuncts exploit our known understanding of chromosomal aberrations commonly observed in various subtypes of RCC. Several notable examples are as follows. First, the majority of clear cell RCCs demonstrate a loss of the short arm of chromosome 3 (3p), in which the von Hippel-Lindau (VHL) gene is located. Second, papillary RCCs typically demonstrate a combination of trisomies (including chromosomes 3, 7, 12, 16, 17, and 20) and loss of the Y chromosome. Third, chromophobe RCCs are associated with a combination of monosomies (including chromosomes 1, 2, 6, 10, 13, 17, and 21). Finally, Xp11 translocation RCCs demonstrate gene fusions involving the transcription factor enhancer 3 (TFE3) gene.30 In this regard, demonstrating nuclear immunoreactivity for TFE3 in the tumor cells can serve as a useful immunohistochemical adjunct to confirm a diagnosis of Xp11 translocation RCC. 1284 Arch Pathol Lab Med—Vol 138, October 2014
Summary In conclusion, cytotechnologists and pathologists, especially cytopathologists, should be familiar with and recognize the cytomorphologic features associated with the various subtypes of RCC. In challenging cases, ancillary immunohistochemical and cytogenetic adjuncts can facilitate the accurate diagnosis and subclassification of RCCs. References 1. Roh MH, Dal Cin P, Silverman SG, Cibas ES. The application of cytogenetics and fluorescence in situ hybridization to fine-needle aspiration in the diagnosis and subclassification of renal neoplasms. Cancer Cytopathol. 2010; 118(3):137–145. 2. Tabatabai ZL, Staerkel GA. Distinguishing primary and metastatic conventional renal cell carcinoma from other malignant neoplasms in fineneedle aspiration biopsy specimens. Arch Pathol Lab Med. 2005;129(8):1017– 1021. 3. Pavlidis N, Briasoulis E, Hainsworth J, Greco FA. Diagnostic and therapeutic management of cancer of an unknown primary. Eur J Cancer. 2003; 39(14):1990–2005. 4. Adams J, Wu HH. The utility of fine-needle aspiration in the diagnosis of primary and metastatic tumors to the lung: a retrospective examination of 1,032 cases. Acta Cytol. 2012;56(6):590–595.
Metastatic Renal Cell Carcinoma on FNA—Lew et al
5. El H, LeBlanc JK, Sherman S, et al. Endoscopic ultrasound-guided biopsy of pancreatic metastases: a large single-center experience. Pancreas. 2013;42(3): 524–530. 6. Gilani SM, Tashjian R, Danforth R, Fathallah L. Metastatic renal cell carcinoma to the pancreas: diagnostic significance of fine-needle aspiration cytology. Acta Cytol. 2013;57(4):418–422. 7. Gilbert CM, Monaco SE, Cooper ST, Khalbuss WE. Endoscopic ultrasoundguided fine-needle aspiration of metastases to the pancreas: a study of 25 cases. Cytojournal. 2011;8:7. 8. Layfield LJ, Hirschowitz SL, Adler DG. Metastatic disease to the pancreas documented by endoscopic ultrasound guided fine-needle aspiration: a sevenyear experience. Diagn Cytopathol. 2012;40(3):228–233. 9. Olson MT, Wakely PE Jr, Ali SZ. Metastases to the pancreas diagnosed by fine-needle aspiration. Acta Cytol. 2013;57(5):473–480. 10. Waters L, Si Q, Caraway N, Mody D, Staerkel G, Sneige N. Secondary tumors of the pancreas diagnosed by endoscopic ultrasound-guided fine-needle aspiration: a 10-year experience [published online ahead of print February 19, 2014]. Diagn Cytopathol. doi:10.1002/dc.23114. 11. Hegerova L, Griebeler ML, Reynolds JP, Henry MR, Gharib H. Metastasis to the thyroid gland: report of a large series from the Mayo clinic [published online ahead of print June 24, 2013]. Am J Clin Oncol. doi:10.1097/COC. 0b013e31829d1d09. ´ L, Cameselle12. Zamarron C, Abdulkader I, Areses MC, Garc´ıa-Paz V, Leon Teijeiro J. Metastases of renal cell carcinoma to the thyroid gland with synchronous benign and malignant follicular cell-derived neoplasms. Case Rep Oncol Med. 2013;2013:485025. 13. Udager AM, Rungta SA. Metastatic renal cell carcinoma, clear cell type, of the parotid gland: a case report, review of literature, and proposed algorithmic approach to salivary gland clear cell neoplasms in fine-needle aspiration biopsies [published online ahead of print February 17, 2014]. Diagn Cytopathol. doi:10. 1002/dc.23103. 14. Fuhrman SA, Lasky LC, Limas C. Prognostic significance of morphologic parameters in renal cell carcinoma. Am J Surg Pathol. 1982;6(7):655–663. 15. Delahunt B, Srigley JR, Montironi R, Egevad L. Advances in renal neoplasia: recommendations from the 2012 International Society of Urological Pathology Consensus Conference [published online ahead of print March 22, 2014]. Urology. 2014;83(5):969–974. doi:10.1016/j.urology.2014.02.004. 16. Sika-Paotonu D, Bethwaite PB, McCredie MR, William Jordan T, Delahunt B. Nucleolar grade but not Fuhrman grade is applicable to papillary renal cell carcinoma. Am J Surg Pathol. 2006;30(9):1091–1096. 17. Truong LD, Todd TD, Dhurandhar B, Ramzy I. Fine-needle aspiration of renal masses in adults: analysis of results and diagnostic problems in 108 cases. Diagn Cytopathol. 1999;20(6):339–349. 18. Amin MB, Corless CL, Renshaw AA, Tickoo SK, Kubus J, Schultz DS. Papillary (chromophil) renal cell carcinoma: histomorphologic characteristics and evaluation of conventional pathologic prognostic parameters in 62 cases. Am J Surg Pathol. 1997;21(6):621–635. 19. Renshaw AA, Corless CL. Papillary renal cell carcinoma: histology and immunohistochemistry. Am J Surg Pathol. 1995;19(7):842–849. 20. Granter SR, Perez-Atayde AR, Renshaw AA. Cytologic analysis of papillary renal cell carcinoma. Cancer. 1998;84(5):303–308. 21. Lim JC, Wojcik EM. Fine-needle aspiration cytology of papillary renal cell carcinoma: the association with concomitant secondary malignancies. Diagn Cytopathol. 2006;34(12):797–800. 22. Delahunt B, Eble JN. Papillary renal cell carcinoma: a clinicopathologic and immunohistochemical study of 105 tumors. Mod Pathol. 1997;10(6):537– 544. 23. Wang S, Filipowicz EA, Schnadig VJ. Abundant intracytoplasmic hemosiderin in both histiocytes and neoplastic cells: a diagnostic pitfall in fine-needle aspiration of cystic papillary renal-cell carcinoma. Diagn Cytopathol. 2001;24(2): 82–85. 24. Weaver MG, al-Kaisi N, Abdul-Karim FW. Fine-needle aspiration cytology of a renal cell adenocarcinoma with massive intracellular hemosiderin accumulation. Diagn Cytopathol. 1991;7(2):147–149. 25. Kunju LP, Wojno K, Wolf JS Jr, Cheng L, Shah RB. Papillary renal cell carcinoma with oncocytic cells and nonoverlapping low grade nuclei: expanding the morphologic spectrum with emphasis on clinicopathologic, immunohistochemical and molecular features. Hum Pathol. 2008;39(1):96–101. 26. Akhtar M, Ali MA. Aspiration cytology of chromophobe cell carcinoma of the kidney. Diagn Cytopathol. 1995;13(4):287–294. 27. Akhtar M, Kardar H, Linjawi T, McClintock J, Ali MA. Chromophobe cell carcinoma of the kidney: a clinicopathologic study of 21 cases. Am J Surg Pathol, 1995;19(11):1245–1256. 28. Salamanca J, Alberti N, Lopez-Rios F, Perez-Barrios A, Mart´ınez-Gonza´lez MA, de Agust´ın P. Fine needle aspiration of chromophobe renal cell carcinoma. Acta Cytol. 2007;51(1):9–15. 29. Aydin H, Chen L, Cheng L, et al. Clear cell tubulopapillary renal cell carcinoma: a study of 36 distinctive low-grade epithelial tumors of the kidney. Am J Surg Pathol. 2010;34(11):1608–1621. 30. Argani P, Hicks J, De Marzo AM, et al. Xp11 translocation renal cell carcinoma (RCC): extended immunohistochemical profile emphasizing novel RCC markers. Am J Surg Pathol. 2010;34(9):1295–1303.
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31. Schinstine M, Filie AC, Torres-Cabala C, et al. Fine-needle aspiration of a Xp11.2 translocation/TFE3 fusion renal cell carcinoma metastatic to the lung: report of a case and review of the literature. Diagn Cytopathol. 2006;34(11):751– 756. 32. Auger M, Katz RL, Sella A, Ordo´ nez ˜ NG, Lawrence DD, Ro JY. Fine-needle aspiration cytology of sarcomatoid renal cell carcinoma: a morphologic and immunocytochemical study of 15 cases. Diagn Cytopathol. 1993;9(1):46–51. 33. Ding GT, Hwang JS, Tan PH. Sarcomatoid renal cell carcinoma metastatic to the breast: report of a case with diagnosis on fine needle aspiration cytology. Acta Cytol. 2007;51(3):451–455. 34. Simsir A, Chhieng D, Wei XJ, Yee H, Waisman J, Cangiarella J. Utility of CD10 and RCCma in the diagnosis of metastatic conventional renal-cell adenocarcinoma by fine-needle aspiration biopsy. Diagn Cytopathol. 2005; 33(1): 3–7. 35. Wasco MJ, Pu RT. Comparison of PAX-2, RCC antigen, and antiphosphorylated H2AX antibody (gamma-H2AX) in diagnosing metastatic renal cell carcinoma by fine-needle aspiration. Diagn Cytopathol. 2008;36(8):568–573. 36. Gokden N, Gokden M, Phan DC, McKenney JK. The utility of PAX-2 in distinguishing metastatic clear cell renal cell carcinoma from its morphologic mimics: an immunohistochemical study with comparison to renal cell carcinoma marker. Am J Surg Pathol. 2008;32(10):1462–1467. 37. Gokden N, Kemp SA, Gokden M. The utility of Pax-2 as an immunohistochemical marker for renal cell carcinoma in cytopathology. Diagn Cytopathol. 2008;36(7):473–477. 38. Knoepp SM, Kunju LP, Roh MH. Utility of PAX8 and PAX2 immunohistochemistry in the identification of renal cell carcinoma in diagnostic cytology. Diagn Cytopathol. 2012;40(8):667–672. 39. Ozcan A, de la Roza G, Ro JY, Shen SS, Truong LD. PAX2 and PAX8 expression in primary and metastatic renal tumors: a comprehensive comparison. Arch Pathol Lab Med. 2012;136(12):1541–1551. 40. Hu Y, Hartmann A, Stoehr C, et al. PAX8 is expressed in the majority of renal epithelial neoplasms: an immunohistochemical study of 223 cases using a mouse monoclonal antibody. J Clin Pathol. 2012;65(3):254–256. 41. Knoepp SM, Placido J, Fields KL, Thomas D, Roh MH. The application of immunocytochemistry to direct smears in the diagnosis of effusions. Diagn Cytopathol. 2013;41(5):425–430. 42. McKnight R, Cohen C, Siddiqui MT. Utility of paired box gene 8 (PAX8) expression in fluid and fine-needle aspiration cytology: an immunohistochemical study of metastatic ovarian serous carcinoma. Cancer Cytopathol. 2010;118(5): 298–302. 43. Ozcan A, Liles N, Coffey D, Shen SS, Truong LD. PAX2 and PAX8 expression in primary and metastatic mullerian epithelial tumors: a comprehen¨ sive comparison. Am J Surg Pathol. 2011;35(12):1837–1847. 44. Tong GX, Devaraj K, Hamele-Bena D, et al. Pax8: a marker for carcinoma of Mullerian origin in serous effusions. Diagn Cytopathol. 2011;39(8):567–574. ¨ 45. Tong GX, Memeo L, Colarossi C, et al. PAX8 and PAX2 immunostaining facilitates the diagnosis of primary epithelial neoplasms of the male genital tract. Am J Surg Pathol. 2011;35(10): 1473–1483. 46. Tong GX, Yu WM, Beaubier NT, et al. Expression of PAX8 in normal and neoplastic renal tissues: an immunohistochemical study. Mod Pathol. 2009;22(9): 1218–1227. 47. Wiseman W, Michael CW, Roh MH. Diagnostic utility of PAX8 and PAX2 immunohistochemistry in the identification of metastatic Mullerian carcinoma in ¨ effusions. Diagn Cytopathol. 2011;39(9):651–656. 48. Laury AR, Perets R, Piao H, et al. A comprehensive analysis of PAX8 expression in human epithelial tumors. Am J Surg Pathol. 2011;35(6):816–826. 49. Shen SS, Truong LD, Scarpelli M, Lopez-Beltran A. Role of immunohistochemistry in diagnosing renal neoplasms: when is it really useful? Arch Pathol Lab Med. 2012;136(4):410–417. 50. Allory Y, Bazile C, Vieillefond A, et al. Profiling and classification tree applied to renal epithelial tumours. Histopathology. 2008;52(2):158–166. 51. Kuroda N, Tanaka A, Ohe C, Nagashima Y. Recent advances of immunohistochemistry for diagnosis of renal tumors. Pathol Int. 2013;63(8): 381–390. 52. Memeo L, Jhang J, Assaad AM, et al. Immunohistochemical analysis for cytokeratin 7, KIT, and PAX2: value in the differential diagnosis of chromophobe cell carcinoma. Am J Clin Pathol. 2007;127(2): 225–229. 53. Ozcan A, Zhai J, Hamilton C, et al. PAX-2 in the diagnosis of primary renal tumors: immunohistochemical comparison with renal cell carcinoma marker antigen and kidney-specific cadherin. Am J Clin Pathol. 2009;131(3):393–404. 54. Gupta R, Balzer B, Picken M, et al. Diagnostic implications of transcription factor Pax 2 protein and transmembrane enzyme complex carbonic anhydrase IX immunoreactivity in adult renal epithelial neoplasms. Am J Surg Pathol. 2009; 33(2):241–247. 55. Rocca PC, Brunelli M, Gobbo S, et al. Diagnostic utility of S100A1 expression in renal cell neoplasms: an immunohistochemical and quantitative RT-PCR study. Mod Pathol. 2007;20(7):722–728. 56. Genega EM, Ghebremichael M, Najarian R, et al. Carbonic anhydrase IX expression in renal neoplasms: correlation with tumor type and grade. Am J Clin Pathol. 2010;134(6):873–879. 57. Dal Cin P, Qian X, Cibas ES. The marriage of cytology and cytogenetics. Cancer Cytopathol. 2013;121(6):279–290.
Metastatic Renal Cell Carcinoma on FNA—Lew et al 1285
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Fine-needle aspiration has assumed an increasingly important role in the diagnosis and management of patients with advanced stage cancer. Given its predilection for metastases to distant sites and organs at the time of presentation, metastatic renal cell carcinoma (RCC) is not infrequently encountered in the setting of fine-needle aspiration for initial diagnosis. In some instances, fineneedle aspiration may be the only opportunity to obtain diagnostic tissue to diagnose and subclassify RCC. Therefore, cytopathologists and cytotechnologists should be familiar with and recognize the cytomorphology of RCC and the ancillary studies that can be used to confirm and subclassify RCC. Herein, we describe a case of metastatic RCC initially diagnosed on fine-needle aspiration, discuss the cytomorphologic features of RCC subtypes, and review pertinent ancillary immunohistochemical and cytogenetic adjuncts. (Arch Pathol Lab Med. 2014;138:1278–1285; doi: 10.5858/arpa.2014-0283-CC)
STUDY CASE 79-year-old man, who initially presented with progressive left-sided weakness with associated facial droop, was found on brain imaging to have a lesion in the right parietal lobe. He underwent a stereotactic biopsy of this lesion, which was nondiagnostic, as it contained only blood and fragments of unremarkable brain parenchyma. Subsequently, the patient underwent computed tomography scans of the chest, abdomen, and pelvis, which demonstrated the presence of bilateral pulmonary nodules, mediastinal and hilar lymphadenopathy, and a left renal mass. The patient did report a remote cigarette smoking history of approximately 20 pack-years. The patient was
A
Accepted for publication June 2, 2014. From the Department of Pathology (Drs Lew and Roh), University of Michigan Health System, Ann Arbor; and the Department of Pathology (Dr Foo), Duke University Medical Center, Durham, North Carolina. The authors have no relevant financial interest in the products or companies described in this article. Presented in part at the New Frontiers in Pathology: An Update for Practicing Pathologists meeting; University of Michigan; September 26–28, 2013; Ann Arbor, Michigan. Reprints: Michael H. Roh, MD, PhD, Department of Pathology, University of Michigan Health System, 2G332 UH, 1500 E Medical Center Dr, Ann Arbor, MI 48109-5054 (e-mail: [email protected]. edu). 1278 Arch Pathol Lab Med—Vol 138, October 2014
referred for endobronchial ultrasound–guided fine-needle aspiration (FNA) to investigate the underlying etiology. PATHOLOGIC FINDINGS A cytopathologist was present on site during the endobronchial ultrasound–guided FNA procedure of a 4L lymph node, during which 13 needle passes were obtained by the bronchoscopist. For each of the first 9 passes, a pair of smears was prepared: 1 air-dried smear and 1 alcohol-fixed smear. The needle was subsequently rinsed in Roswell Park Memorial Institute (RPMI) medium. Each air-dried smear was immediately Diff-Quik stained for on-site microscopic examination. The alcohol-fixed smears were set aside for Papanicolaou staining in the cytopathology laboratory to be completed after the conclusion of the procedure. Microscopic examination of the air-dried, Diff-Quik–stained smears demonstrated a hypocellular aspirate that was significant for a population of malignant-appearing epithelioid cells, arranged predominantly in sheets and small clusters (Figure 1, A). On higher magnification, marked nuclear pleomorphism, conspicuous nucleoli, and prominently vacuolated cytoplasm were appreciated; there was variability to the extent of cytoplasmic vacuolization, which ranged from fine vacuoles to large vacuoles (Figure 1, B). During the on-site evaluation, the malignant cells were identified on only 2 of the 9 Diff-Quik–stained smears; the other 7 smears consisted of predominantly blood. After the first 9 needle passes were obtained, 4 dedicated passes for the RPMI needle rinse, for the production of a cell block, were obtained. Given the cytomorphology appreciated during the on-site preliminary assessment, there was already a high index of suspicion for a metastatic renal cell carcinoma (RCC), clear cell type. After the conclusion of the FNA procedure, Papanicolaoustained smears were available for microscopic evaluation. Similar to the Diff-Quik–stained smears, the tumor cellularity on the Papanicolaou-stained smears was low overall. Nonetheless, a few clusters of malignant epithelial cells with delicate, frothy cytoplasm were appreciated (Figure 2, A and B). The cell block contained a few sheetlike clusters of tumor cells and was used for confirmatory immunohistochemistry. The tumor cells exhibited cytoplasmic immunoreactivity for CD10 and nuclear reactivity for paired box gene (PAX) 8 (Figure 2, C and D, respectively). Immunostains for cytokeratin 7 and RCC marker (RCCma) were negative (not shown). Overall, the cytomorphologic features and immunophenotype were consistent with a diagnosis of metastatic RCC, clear cell type. Metastatic Renal Cell Carcinoma on FNA—Lew et al
Figure 1. A, Examination of a stained cytologic direct smear on low magnification, during the on-site assessment, reveals the presence of neoplastic epithelial cells arranged in sheets and small clusters. B, On higher magnification, marked nuclear pleomorphism, prominent nucleoli, and overt vacuolization to the cytoplasm are evident in the tumor cells (Diff-Quik stain, original magnifications 3100 [A] and 3600 [B]).
COMMENT Fine-needle aspiration has emerged as an increasingly important modality used for the diagnosis of primary and metastatic RCCs.1,2 Confirming the diagnosis of RCC in the setting of metastatic disease enables appropriate pathologic staging, thereby facilitating appropriate clinical management.3 Although RCC represents approximately only 2% of visceral cancers, RCCs can occasionally be encountered in the setting of extrarenal FNAs, given its propensity to metastasize to distant sites.2 Previous published series specifically addressing metastatic carcinomas to various organ sites have consistently demonstrated RCC to be a common source of metastasis to extrarenal organs. For instance, RCC represents the most frequent source of metastasis encountered in lung FNAs.4 Although metastases to the pancreas are generally rare occurrences, RCC represents the most common primary etiology when metastatic tumors are encountered in the pancreas.5–10 Similarly, metastases to the thyroid gland are uncommon; nonetheless, RCC represents the most commonly encountered metastatic tumor in thyroid FNAs.11,12 Metastatic RCCs diagnosed in parotid gland FNAs have also been reported.13 As RCC may be encountered initially in the setting of metastatic disease or many years after the initial diagnosis of the primary tumor,2,8,9,11,13 it is important for cytopathologists and cytotechnologists to recognize the cytomorphologic features of RCC and its subtypes and to be familiar with ancillary studies that can aid in the diagnosis and subclassification of RCCs. Cytomorphologic Features of RCC Subtypes The cytomorphologic features of a given RCC can vary depending on its subtype as well as grade. The most common subtype of RCC is the classic or conventional (clear cell) type. As illustrated by the above case, biopsies of these lesions can be bloody and FNAs of these lesions can be very hemodilute, given the high vascularity of these tumors. These factors may result in a nondiagnostic sample. However, tumor cells, when present, are typically characArch Pathol Lab Med—Vol 138, October 2014
terized by low nuclear to cytoplasmic ratios. Nuclei can be centrally or eccentrically placed and their characteristics vary according to grade. Low-grade (Fuhrman grade 1–2) tumors have smooth to slightly irregular nuclear contours and nucleoli discernible only at high-power magnification (.3200), whereas high-grade (Fuhrman grade 3–4) tumors will have increasingly irregular nuclei, prominent nucleoli visualized at 3100, and increased pleomorphism, which may manifest as highly bizarre cells (Figure 3, A through D).14 In light of recent studies that have shown that nucleolar size alone is a more powerful prognostic parameter than any other cytologic feature in clear cell RCC, the 2012 International Society of Urological Pathology Consensus Conference recommended the use of a grading system based on nucleolar prominence alone.15,16 The cytoplasm of these tumor cells can be wispy, granular, vacuolated, or a mixture thereof.17 In high-grade tumors, the cytoplasm often takes a more coarsely granular appearance, which confers a more oncocytic appearance to the tumor. However, higher nuclear grade features typically accompany this change, which are not as commonly seen in other oncocytic renal neoplasms. The tumor cells of clear cell RCC are commonly arranged in sheets and clusters in which cell boundaries are ill defined. However, these tumor cells can present singly as well, particularly in higher-grade tumors in which there is an increased amount of cellular discohesion. The next most common subtype of RCC is the papillary type. This subtype is defined by papillary or tubulopapillary growth patterns, which compose more than 50% of the tumor.18,19 Aspirates of papillary RCC are often very cellular and consist of papillary fragments of cells. Unlike the short papillae that can occasionally be seen in clear cell RCC, the papillae in papillary RCCs are often long with complex branching architecture, easily appreciated on low magnification (Figure 4, A). Surrounding tumor cells may also be arranged in tight clusters or spherules.20,21 Papillary RCCs have a spectrum of morphologies, but have historically been subdivided into 2 main histologic subtypes, type 1 and type 2, which correlate with low- and high-grade morphologic Metastatic Renal Cell Carcinoma on FNA—Lew et al 1279
Figure 2. A and B, Cohesive sheets of tumor cells exhibiting vacuolated cytoplasm are seen. C, Immunohistochemistry performed on formalin-fixed, paraffin-embedded cell block sections reveals strong, diffuse cytoplasmic immunoreactivity for CD10 in the tumor. D, Immunohistochemistry performed on formalin-fixed, paraffin-embedded cell block sections reveal strong, diffuse nuclear immunoreactivity for PAX8 in the tumor (Papanicolaou stain, original magnifications 3400 [A and B]; original magnifications 3200 [C] and 3400 [D]).
features, respectively. In type 1 papillary RCCs, the cells are often small to medium in size and cuboidal in shape, and have uniform, round nuclei with even chromatin distribution, inconspicuous nucleoli, and scant to moderate amounts of cytoplasm. Type 2 papillary RCCs demonstrate larger cells and, similar to the cells of high-grade clear cell RCC, these cells display enlarged nuclei with prominent nucleoli and a moderate to abundant amount of granular cytoplasm.17,21,22 Given that other RCC subtypes can occasionally demonstrate a papillary-like architecture on FNA, papillary architecture with true fibrovascular cores as well as ancillary studies, discussed below, are helpful in confirming a diagnosis of papillary RCC. Another helpful morphologic feature that one can identify in FNAs of papillary RCCs is foamy macrophages within papillae as well as in the background (Figure 4, B and C). Hemosiderin deposition in tumor cells as well as macrophages is also a feature associated with papillary RCC.20,23,24 A more uncommon variant of papillary RCC is the more recently described papillary RCC with oncocytic cells.25 The cytomorphology of these tumor cells raise the differential diagnostic considerations of oncocytoma and chromophobe 1280 Arch Pathol Lab Med—Vol 138, October 2014
RCC. However, the presence of true fibrovascular cores should allow for identification of this papillary RCC variant. Next, chromophobe RCC is less common than the clear cell and papillary subtypes of RCC. Cytologic preparations are often cellular, with tumor cells arranged singly or in loosely cohesive cell groups. Key characteristics in these tumor cells include centrally placed nuclei with dark chromatin, perinuclear clearing, and abundant amounts of cytoplasm, resulting in a koilocytic appearance.26,27 Binucleation and nuclear pleomorphism are also commonly seen (Figure 5).17,28 The cytomorphologic features of chromophobe RCC can be mimicked by oncocytomas and, occasionally, eosinophilic variants of clear cell RCC. Therefore, ancillary studies, discussed below, can be used to assist in definitive classification for diagnostically challenging cases. One of the more recently described subtypes of RCC is the clear cell tubulopapillary RCC. These tumors are considered low-grade tumors and typically affect patients with endstage renal disease. Review of surgical resection specimens reveals that these tumors typically contain a mixture of cysts, papillae, tubules, acini, and solid nests of tumor cells, which Metastatic Renal Cell Carcinoma on FNA—Lew et al
Figure 3. Cytomorphology of clear cell renal cell carcinoma (RCC). A, Low-grade clear cell RCC demonstrates tumor cells in cohesive clusters. Tumor cells have abundant vacuolated to granular cytoplasm that often appears thin and wispy, with ill-defined cell membranes. B, Nuclei have relatively smooth nuclear contours and minimal cytologic atypia. Nucleoli are generally small and inconspicuous. C and D, High-grade clear cell RCCs display decreased cellular cohesion. Marked nuclear pleomorphism and prominent macronucleoli are present and the cytoplasm exhibits a more dense appearance with only fine vacuolization (Diff-Quik stain, original magnifications 3400 [A] and 3200 [C]; Papanicolaou stain, original magnifications 3400 [B and D]).
are characterized by bland nuclei, scant to moderate amounts of eosinophilic to clear cytoplasm, and reverse polarization of nuclei.29 Distinctive cytomorphologic features on smear preparations have not yet been clearly defined in the literature. However, similar to reports on surgical resection specimens, these tumor cells display nuclei with smooth nuclear contours, even chromatin, inconspicuous nucleoli, and scant to moderate amounts of finely granular to vacuolated cytoplasm (Figure 6, A). Although the smear preparations may show nonspecific findings, adequately cellular cell block preparations are helpful in displaying architectural patterns such as tubules, trabeculae, and papillary structures, as well as reverse polarization of tumor cells, that characterize these tumors (Figure 6, B). Another recently described renal tumor is the Xp11 translocation–associated RCC.30 These tumors are predominantly found in children and young adults, although there have been cases described in older patients. In surgical resection specimens, these tumors demonstrate clear cells arranged in papillary structures with dense hyaline cores. Arch Pathol Lab Med—Vol 138, October 2014
On cytology specimens, the tumor cells have eccentrically placed nuclei, irregular nuclear contours, variably prominent nucleoli, and abundant clear to granular cytoplasm, which mimics the appearance of clear cell RCC. Helpful features on smear preparations include the layering of tumor cells around dense, hyalinized central cores.31 The involvement of a younger patient and this unusual architectural arrangement of clear cells may clue a cytopathologist in to this entity. However, ancillary studies, discussed below, are usually helpful for confirming the diagnosis. Finally, sarcomatoid dedifferentiation of a RCC occurs in approximately 3% to 5% of RCCs.32,33 Cytologic preparations demonstrate a biphasic appearance that includes a high-grade epithelial component admixed with malignantappearing spindle cells. The nuclear atypia within the sarcomatoid component can vary greatly, from more uniformly spindled nuclei akin to those seen in fibrosarcomas to bizarre, pleomorphic nuclei similar to those seen in undifferentiated pleomorphic sarcomas. However, it is important to note that the relative proportions of epithelioid and sarcomatoid components depend on the sampling of Metastatic Renal Cell Carcinoma on FNA—Lew et al 1281
Figure 4. Cytomorphology of papillary renal cell carcinoma (RCC). A, In this low-magnification photomicrograph, a long, branching papillary cluster with a fibrovascular core can be appreciated. B, Foamy macrophages within the fibrovascular core and adjacent to the papillary cluster can be appreciated. C, The nuclei display minimal cytologic atypia and pleomorphism. These photomicrographs were obtained from aspirates of type 1 papillary RCC (Diff-Quik stain, original magnifications 3100 [A] and 3400 [B]; Papanicolaou stain, original magnification 3200 [C]).
Immunohistochemical Adjuncts to Assist in the Subclassification of the Common Renal Epithelial Tumors Expected Immunophenotype of Common RCC Subtypes and Oncocytoma Encountered in Cytology Marker RCC marker CD10 Vimentin CK7 PAX2 CD117/c-kit CAIX (high expression) AMACR S100A1
Clear Cell RCC þ þ þ þ þ þ
Papillary RCC
Chromophobe RCC
Oncocytoma
þ þ þ þ þ þ þ
/þ þ þ
þ þ þ
Abbreviations: AMACR, a-methylacyl coenzyme A racemase; CAIX, carbonic anhydrase IX; CD, cluster of differentiation; CK, cytokeratin; PAX2, paired box 2; RCC, renal cell carcinoma. 1282 Arch Pathol Lab Med—Vol 138, October 2014
Metastatic Renal Cell Carcinoma on FNA—Lew et al
Figure 5. Cytomorphology of chromophobe renal cell carcinoma (RCC). Aspirates of chromophobe RCC tend to be cellular samples composed of discohesive tumor cells characterized by abundant granular cytoplasm. The characteristic perinuclear clearing confers a koilocytic appearance (DiffQuik stain, original magnification 3400 [A]; Papanicolaou stain, original magnification 3400 [B]).
the tumor. Given the poor prognostic implications of sarcomatoid change in a RCC, it is important to recognize as well as mention the presence of a sarcomatoid component in diagnostic reports when encountered in cytologic samples. Immunohistochemical Adjuncts for the Identification of Metastatic RCC Traditionally, RCCma and CD10 are commonly used for the immunohistochemical confirmation of metastatic RCC. Nonetheless, there are limitations associated with the use of either marker. Although RCCma is highly specific for RCC, the use of RCCma as a confirmatory immunomarker in diagnostic cytology is limited by its relatively low sensitivity of below 60%.34,35 On the other hand, CD10 immunostaining is highly sensitive for detecting metastatic RCC but is limited by its low specificity. Specifically, in their series, Simsir and colleagues34 found that CD10 immunohistochemistry was 100% sensitive but only 59% specific for detection of metastatic RCC. Recently, members of the PAX family of transcription factors, PAX2 and PAX8, have emerged as useful immunohistochemical adjuncts for the diagnosis of metastatic RCC.35–38 Both PAX2- and PAX8-positive tumors display nuclear immunoreactivity for these markers. The sensitivity of PAX8 for detecting metastatic RCC is the highest and exceeds that of PAX2,38,39 which, in turn, exceeds the sensitivity of RCCma.36 PAX8 plays a critical role in the development of the kidney, the thyroid gland, and the female genital tract, and its expression is maintained in carcinomas derived from those sites.38–47 In their large series, Laury and colleagues48 reported that PAX8 immunoreactivity was observed in 93%, 76%, and 80% of clear cell, papillary, and chromophobe RCCs, respectively, and in virtually almost all mullerian serous carcinomas and thyroid ¨ carcinomas. Therefore, although PAX8 immunoreactivity is not exclusively observed in renal cancers, PAX8 immunohistochemistry serves as a useful diagnostic adjunct given its very high sensitivity. In the aforementioned case, the tumor cells demonstrated diffuse, strong immunoreactivity for both PAX8 and CD10, supporting of the diagnosis of metastatic RCC. Arch Pathol Lab Med—Vol 138, October 2014
Immunohistochemical and Cytogenetic Adjuncts for the Subclassification of RCC Challenges can be encountered in the subclassification of RCCs in small biopsies and FNAs. The importance of subclassification on these specimens, which may be the only opportunity to obtain diagnostic tissue, rests on prognostic and therapeutic management implications.1 Immunohistochemistry can serve as a useful adjunct to conventional cytomorphologic evaluation in the subclassification of RCCs.49 The use of panels of immunomarkers rather than a single marker alone is prudent, as the expression of any single marker is not entirely specific for a given entity. Despite variations in immunophenotypes associated with various subtypes of RCC, the expected immunophenotypes for the commonly encountered subtypes of RCC along with oncocytoma in FNA samples are summarized in the Table. The expression of RCCma, CD10, and vimentin tends to be observed mostly in clear cell and papillary RCCs; however, of the 3, the sensitivity of RCCma is the lowest.50–53 Cytokeratin 7 (CK7) is a useful marker in distinguishing papillary and chromophobe RCCs from clear cell RCCs. Clear cell RCCs tend to be CK7 negative, whereas papillary and chromophobe RCCs are usually CK7 positive.50,52 The expression of PAX2 is predominantly observed in the clear cell and the papillary RCCs; however, chromophobe RCCs usually are PAX2 negative.52,54 CD117/ c-kit expression is frequently observed in chromophobe RCCs and oncocytomas but not the clear cell or papillary subtypes of RCC.52 In this regard, S100A1 serves as a useful marker to distinguish between these two entities, as oncocytomas are typically S100A1þ, whereas chromophobe RCCs are S100A1.55 Strong, diffuse immunoreactivity for carbonic anhydrase IX and positivity for a-methylacyl coenzyme A racemase support a diagnosis of the clear cell and papillary subtypes of RCC, respectively.50,51,54,56 Next, the identification of clear cell tubulopapillary RCC can be confirmed by demonstrating immunoreactivity for CK7 (Figure 6, C) and carbonic anhydrase IX (variable), but negativity for CD10 and a-methylacyl coenzyme A racemase (Figure 6, D).29 Metastatic Renal Cell Carcinoma on FNA—Lew et al 1283
Figure 6. Cytomorphology and immunophenotypic features of clear cell tubulopapillary renal cell carcinoma (RCC). A, The cytomorphologic features of these tumors are not yet clearly defined, but tumors typically demonstrate minimal nuclear atypia and pleomorphism. B, This cellular cell block preparation highlights tubules and papillary structures lined by clear cells with reverse polarity; nuclei are aligned away from the basement membrane. C and D, Immunohistochemistry can be helpful in confirming a diagnosis of clear cell tubulopapillary RCC. Tumor cells are typically immunoreactive for cytokeratin 7 (C) and negative for a-methylacyl coenzyme A racemase (D) (Diff-Quik stain, original magnification 3400 [A]; hematoxylin-eosin, original magnification 3400 [B]; original magnifications 3400 [C and D]).
Finally, conventional cytogenetics and fluorescence in situ hybridization can be used to assist in the subclassification of RCCs.1,57 These adjuncts exploit our known understanding of chromosomal aberrations commonly observed in various subtypes of RCC. Several notable examples are as follows. First, the majority of clear cell RCCs demonstrate a loss of the short arm of chromosome 3 (3p), in which the von Hippel-Lindau (VHL) gene is located. Second, papillary RCCs typically demonstrate a combination of trisomies (including chromosomes 3, 7, 12, 16, 17, and 20) and loss of the Y chromosome. Third, chromophobe RCCs are associated with a combination of monosomies (including chromosomes 1, 2, 6, 10, 13, 17, and 21). Finally, Xp11 translocation RCCs demonstrate gene fusions involving the transcription factor enhancer 3 (TFE3) gene.30 In this regard, demonstrating nuclear immunoreactivity for TFE3 in the tumor cells can serve as a useful immunohistochemical adjunct to confirm a diagnosis of Xp11 translocation RCC. 1284 Arch Pathol Lab Med—Vol 138, October 2014
Summary In conclusion, cytotechnologists and pathologists, especially cytopathologists, should be familiar with and recognize the cytomorphologic features associated with the various subtypes of RCC. In challenging cases, ancillary immunohistochemical and cytogenetic adjuncts can facilitate the accurate diagnosis and subclassification of RCCs. References 1. Roh MH, Dal Cin P, Silverman SG, Cibas ES. The application of cytogenetics and fluorescence in situ hybridization to fine-needle aspiration in the diagnosis and subclassification of renal neoplasms. Cancer Cytopathol. 2010; 118(3):137–145. 2. Tabatabai ZL, Staerkel GA. Distinguishing primary and metastatic conventional renal cell carcinoma from other malignant neoplasms in fineneedle aspiration biopsy specimens. Arch Pathol Lab Med. 2005;129(8):1017– 1021. 3. Pavlidis N, Briasoulis E, Hainsworth J, Greco FA. Diagnostic and therapeutic management of cancer of an unknown primary. Eur J Cancer. 2003; 39(14):1990–2005. 4. Adams J, Wu HH. The utility of fine-needle aspiration in the diagnosis of primary and metastatic tumors to the lung: a retrospective examination of 1,032 cases. Acta Cytol. 2012;56(6):590–595.
Metastatic Renal Cell Carcinoma on FNA—Lew et al
5. El H, LeBlanc JK, Sherman S, et al. Endoscopic ultrasound-guided biopsy of pancreatic metastases: a large single-center experience. Pancreas. 2013;42(3): 524–530. 6. Gilani SM, Tashjian R, Danforth R, Fathallah L. Metastatic renal cell carcinoma to the pancreas: diagnostic significance of fine-needle aspiration cytology. Acta Cytol. 2013;57(4):418–422. 7. Gilbert CM, Monaco SE, Cooper ST, Khalbuss WE. Endoscopic ultrasoundguided fine-needle aspiration of metastases to the pancreas: a study of 25 cases. Cytojournal. 2011;8:7. 8. Layfield LJ, Hirschowitz SL, Adler DG. Metastatic disease to the pancreas documented by endoscopic ultrasound guided fine-needle aspiration: a sevenyear experience. Diagn Cytopathol. 2012;40(3):228–233. 9. Olson MT, Wakely PE Jr, Ali SZ. Metastases to the pancreas diagnosed by fine-needle aspiration. Acta Cytol. 2013;57(5):473–480. 10. Waters L, Si Q, Caraway N, Mody D, Staerkel G, Sneige N. Secondary tumors of the pancreas diagnosed by endoscopic ultrasound-guided fine-needle aspiration: a 10-year experience [published online ahead of print February 19, 2014]. Diagn Cytopathol. doi:10.1002/dc.23114. 11. Hegerova L, Griebeler ML, Reynolds JP, Henry MR, Gharib H. Metastasis to the thyroid gland: report of a large series from the Mayo clinic [published online ahead of print June 24, 2013]. Am J Clin Oncol. doi:10.1097/COC. 0b013e31829d1d09. ´ L, Cameselle12. Zamarron C, Abdulkader I, Areses MC, Garc´ıa-Paz V, Leon Teijeiro J. Metastases of renal cell carcinoma to the thyroid gland with synchronous benign and malignant follicular cell-derived neoplasms. Case Rep Oncol Med. 2013;2013:485025. 13. Udager AM, Rungta SA. Metastatic renal cell carcinoma, clear cell type, of the parotid gland: a case report, review of literature, and proposed algorithmic approach to salivary gland clear cell neoplasms in fine-needle aspiration biopsies [published online ahead of print February 17, 2014]. Diagn Cytopathol. doi:10. 1002/dc.23103. 14. Fuhrman SA, Lasky LC, Limas C. Prognostic significance of morphologic parameters in renal cell carcinoma. Am J Surg Pathol. 1982;6(7):655–663. 15. Delahunt B, Srigley JR, Montironi R, Egevad L. Advances in renal neoplasia: recommendations from the 2012 International Society of Urological Pathology Consensus Conference [published online ahead of print March 22, 2014]. Urology. 2014;83(5):969–974. doi:10.1016/j.urology.2014.02.004. 16. Sika-Paotonu D, Bethwaite PB, McCredie MR, William Jordan T, Delahunt B. Nucleolar grade but not Fuhrman grade is applicable to papillary renal cell carcinoma. Am J Surg Pathol. 2006;30(9):1091–1096. 17. Truong LD, Todd TD, Dhurandhar B, Ramzy I. Fine-needle aspiration of renal masses in adults: analysis of results and diagnostic problems in 108 cases. Diagn Cytopathol. 1999;20(6):339–349. 18. Amin MB, Corless CL, Renshaw AA, Tickoo SK, Kubus J, Schultz DS. Papillary (chromophil) renal cell carcinoma: histomorphologic characteristics and evaluation of conventional pathologic prognostic parameters in 62 cases. Am J Surg Pathol. 1997;21(6):621–635. 19. Renshaw AA, Corless CL. Papillary renal cell carcinoma: histology and immunohistochemistry. Am J Surg Pathol. 1995;19(7):842–849. 20. Granter SR, Perez-Atayde AR, Renshaw AA. Cytologic analysis of papillary renal cell carcinoma. Cancer. 1998;84(5):303–308. 21. Lim JC, Wojcik EM. Fine-needle aspiration cytology of papillary renal cell carcinoma: the association with concomitant secondary malignancies. Diagn Cytopathol. 2006;34(12):797–800. 22. Delahunt B, Eble JN. Papillary renal cell carcinoma: a clinicopathologic and immunohistochemical study of 105 tumors. Mod Pathol. 1997;10(6):537– 544. 23. Wang S, Filipowicz EA, Schnadig VJ. Abundant intracytoplasmic hemosiderin in both histiocytes and neoplastic cells: a diagnostic pitfall in fine-needle aspiration of cystic papillary renal-cell carcinoma. Diagn Cytopathol. 2001;24(2): 82–85. 24. Weaver MG, al-Kaisi N, Abdul-Karim FW. Fine-needle aspiration cytology of a renal cell adenocarcinoma with massive intracellular hemosiderin accumulation. Diagn Cytopathol. 1991;7(2):147–149. 25. Kunju LP, Wojno K, Wolf JS Jr, Cheng L, Shah RB. Papillary renal cell carcinoma with oncocytic cells and nonoverlapping low grade nuclei: expanding the morphologic spectrum with emphasis on clinicopathologic, immunohistochemical and molecular features. Hum Pathol. 2008;39(1):96–101. 26. Akhtar M, Ali MA. Aspiration cytology of chromophobe cell carcinoma of the kidney. Diagn Cytopathol. 1995;13(4):287–294. 27. Akhtar M, Kardar H, Linjawi T, McClintock J, Ali MA. Chromophobe cell carcinoma of the kidney: a clinicopathologic study of 21 cases. Am J Surg Pathol, 1995;19(11):1245–1256. 28. Salamanca J, Alberti N, Lopez-Rios F, Perez-Barrios A, Mart´ınez-Gonza´lez MA, de Agust´ın P. Fine needle aspiration of chromophobe renal cell carcinoma. Acta Cytol. 2007;51(1):9–15. 29. Aydin H, Chen L, Cheng L, et al. Clear cell tubulopapillary renal cell carcinoma: a study of 36 distinctive low-grade epithelial tumors of the kidney. Am J Surg Pathol. 2010;34(11):1608–1621. 30. Argani P, Hicks J, De Marzo AM, et al. Xp11 translocation renal cell carcinoma (RCC): extended immunohistochemical profile emphasizing novel RCC markers. Am J Surg Pathol. 2010;34(9):1295–1303.
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31. Schinstine M, Filie AC, Torres-Cabala C, et al. Fine-needle aspiration of a Xp11.2 translocation/TFE3 fusion renal cell carcinoma metastatic to the lung: report of a case and review of the literature. Diagn Cytopathol. 2006;34(11):751– 756. 32. Auger M, Katz RL, Sella A, Ordo´ nez ˜ NG, Lawrence DD, Ro JY. Fine-needle aspiration cytology of sarcomatoid renal cell carcinoma: a morphologic and immunocytochemical study of 15 cases. Diagn Cytopathol. 1993;9(1):46–51. 33. Ding GT, Hwang JS, Tan PH. Sarcomatoid renal cell carcinoma metastatic to the breast: report of a case with diagnosis on fine needle aspiration cytology. Acta Cytol. 2007;51(3):451–455. 34. Simsir A, Chhieng D, Wei XJ, Yee H, Waisman J, Cangiarella J. Utility of CD10 and RCCma in the diagnosis of metastatic conventional renal-cell adenocarcinoma by fine-needle aspiration biopsy. Diagn Cytopathol. 2005; 33(1): 3–7. 35. Wasco MJ, Pu RT. Comparison of PAX-2, RCC antigen, and antiphosphorylated H2AX antibody (gamma-H2AX) in diagnosing metastatic renal cell carcinoma by fine-needle aspiration. Diagn Cytopathol. 2008;36(8):568–573. 36. Gokden N, Gokden M, Phan DC, McKenney JK. The utility of PAX-2 in distinguishing metastatic clear cell renal cell carcinoma from its morphologic mimics: an immunohistochemical study with comparison to renal cell carcinoma marker. Am J Surg Pathol. 2008;32(10):1462–1467. 37. Gokden N, Kemp SA, Gokden M. The utility of Pax-2 as an immunohistochemical marker for renal cell carcinoma in cytopathology. Diagn Cytopathol. 2008;36(7):473–477. 38. Knoepp SM, Kunju LP, Roh MH. Utility of PAX8 and PAX2 immunohistochemistry in the identification of renal cell carcinoma in diagnostic cytology. Diagn Cytopathol. 2012;40(8):667–672. 39. Ozcan A, de la Roza G, Ro JY, Shen SS, Truong LD. PAX2 and PAX8 expression in primary and metastatic renal tumors: a comprehensive comparison. Arch Pathol Lab Med. 2012;136(12):1541–1551. 40. Hu Y, Hartmann A, Stoehr C, et al. PAX8 is expressed in the majority of renal epithelial neoplasms: an immunohistochemical study of 223 cases using a mouse monoclonal antibody. J Clin Pathol. 2012;65(3):254–256. 41. Knoepp SM, Placido J, Fields KL, Thomas D, Roh MH. The application of immunocytochemistry to direct smears in the diagnosis of effusions. Diagn Cytopathol. 2013;41(5):425–430. 42. McKnight R, Cohen C, Siddiqui MT. Utility of paired box gene 8 (PAX8) expression in fluid and fine-needle aspiration cytology: an immunohistochemical study of metastatic ovarian serous carcinoma. Cancer Cytopathol. 2010;118(5): 298–302. 43. Ozcan A, Liles N, Coffey D, Shen SS, Truong LD. PAX2 and PAX8 expression in primary and metastatic mullerian epithelial tumors: a comprehen¨ sive comparison. Am J Surg Pathol. 2011;35(12):1837–1847. 44. Tong GX, Devaraj K, Hamele-Bena D, et al. Pax8: a marker for carcinoma of Mullerian origin in serous effusions. Diagn Cytopathol. 2011;39(8):567–574. ¨ 45. Tong GX, Memeo L, Colarossi C, et al. PAX8 and PAX2 immunostaining facilitates the diagnosis of primary epithelial neoplasms of the male genital tract. Am J Surg Pathol. 2011;35(10): 1473–1483. 46. Tong GX, Yu WM, Beaubier NT, et al. Expression of PAX8 in normal and neoplastic renal tissues: an immunohistochemical study. Mod Pathol. 2009;22(9): 1218–1227. 47. Wiseman W, Michael CW, Roh MH. Diagnostic utility of PAX8 and PAX2 immunohistochemistry in the identification of metastatic Mullerian carcinoma in ¨ effusions. Diagn Cytopathol. 2011;39(9):651–656. 48. Laury AR, Perets R, Piao H, et al. A comprehensive analysis of PAX8 expression in human epithelial tumors. Am J Surg Pathol. 2011;35(6):816–826. 49. Shen SS, Truong LD, Scarpelli M, Lopez-Beltran A. Role of immunohistochemistry in diagnosing renal neoplasms: when is it really useful? Arch Pathol Lab Med. 2012;136(4):410–417. 50. Allory Y, Bazile C, Vieillefond A, et al. Profiling and classification tree applied to renal epithelial tumours. Histopathology. 2008;52(2):158–166. 51. Kuroda N, Tanaka A, Ohe C, Nagashima Y. Recent advances of immunohistochemistry for diagnosis of renal tumors. Pathol Int. 2013;63(8): 381–390. 52. Memeo L, Jhang J, Assaad AM, et al. Immunohistochemical analysis for cytokeratin 7, KIT, and PAX2: value in the differential diagnosis of chromophobe cell carcinoma. Am J Clin Pathol. 2007;127(2): 225–229. 53. Ozcan A, Zhai J, Hamilton C, et al. PAX-2 in the diagnosis of primary renal tumors: immunohistochemical comparison with renal cell carcinoma marker antigen and kidney-specific cadherin. Am J Clin Pathol. 2009;131(3):393–404. 54. Gupta R, Balzer B, Picken M, et al. Diagnostic implications of transcription factor Pax 2 protein and transmembrane enzyme complex carbonic anhydrase IX immunoreactivity in adult renal epithelial neoplasms. Am J Surg Pathol. 2009; 33(2):241–247. 55. Rocca PC, Brunelli M, Gobbo S, et al. Diagnostic utility of S100A1 expression in renal cell neoplasms: an immunohistochemical and quantitative RT-PCR study. Mod Pathol. 2007;20(7):722–728. 56. Genega EM, Ghebremichael M, Najarian R, et al. Carbonic anhydrase IX expression in renal neoplasms: correlation with tumor type and grade. Am J Clin Pathol. 2010;134(6):873–879. 57. Dal Cin P, Qian X, Cibas ES. The marriage of cytology and cytogenetics. Cancer Cytopathol. 2013;121(6):279–290.
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