Novel Insights from Clinical Practice Acta Cytologica 2014;58:419–426 DOI: 10.1159/000365272
Received: February 10, 2014 Accepted after revision: June 6, 2014 Published online: August 14, 2014
Cytological Features of Carcinosarcoma ex Pleomorphic Adenoma of the Parotid Gland: A Case Report Naoyo Ishikura a Takako Kawada b Masaki Mori c Hideki Maegawa c Makoto Ohta d Yoshiaki Imamura c a
Department of Pathology and Laboratory Medicine, Nagoya University Hospital, Nagoya, b Department of Cytopathology, Maizuru Kyosai Hospital, Kyoto, c Division of Surgical Pathology, University of Fukui Hospital, and d Department of Pathology, Fukui Red Cross Hospital, Fukui, Japan
Established Facts • Carcinosarcoma of the salivary gland is an extremely rare tumor composed of both carcinomatous and sarcomatous components. In cytology, both components may appear on the smears. • One third to a half of cases arise from a preexisting pleomorphic adenoma.
Novel Insights • Hyaline globules showing metachromasia on Giemsa staining, as observed in this case, have not been previously reported in other carcinosarcoma cases. • This is the second case report describing the cytological findings of carcinosarcoma ex pleomorphic adenoma of the salivary gland.
Abstract Background: Carcinosarcoma of the salivary gland is an extremely rare tumor composed of carcinomatous and sarcomatoid components. This report describes the cytological and pathological findings of a case of carcinosarcoma ex pleomorphic adenoma arising in the right parotid gland.
© 2014 S. Karger AG, Basel 0001–5547/14/0584–0419$39.50/0 E-Mail [email protected] www.karger.com/acy
Case: A 47-year-old female visited a hospital with swelling of the right parotid region, slight pain and facial palsy. Fine-needle aspiration smears showed both clustered epithelium-like cells and singly scattered cells in a necrotic background. The cells, especially the latter, exhibited significant cellular pleomorphism and had irregularly shaped nuclei. Myxoid stromalike cell clusters without cellular atypism were also seen. The right parotid gland was resected, and the tumor tissue was histologically diagnosed as carcinosarcoma ex pleomorphic adenoma. Conclusion: The cytological findings of carcinosarcoma ex pleomorphic adenoma have been reported in very
Correspondence to: Dr. Naoyo Ishikura Department of Pathology and Laboratory Medicine, Nagoya University Hospital 65 Tsurumai-cho, Showa-ku Nagoya 466-8560 (Japan) E-Mail ishikuranao @ med.nagoya-u.ac.jp
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Key Words Carcinosarcoma · Pleomorphic adenoma · Salivary gland neoplasms · Fine-needle aspiration cytology
© 2014 S. Karger AG, Basel
Introduction
Carcinosarcoma is a high-grade malignant neoplasm composed of a mixture of both carcinomatous and sarcomatous components [1]. Carcinosarcoma of the salivary gland is an extremely rare tumor, comprising only 0.04– 0.16% of all salivary gland tumors and 0.4% of all malignant salivary gland neoplasms [2, 3]. It usually arises in the major salivary glands in elderly patients and causes swelling of the salivary glands with pain and facial palsy [2, 3]. Most carcinosarcomas develop de novo; however, one third to a half of cases occur in association with benign pleomorphic adenoma [4, 5]. This report describes the cytological and histological findings of a case of carcinosarcoma ex pleomorphic adenoma of the right parotid gland. Case Report A 47-year-old female visited a neighboring hospital with swelling of the right parotid gland of 5-month’s duration. She also complained of mild pain and facial palsy. Her family history and past history were unremarkable. Ultrasonography, computerized tomography and magnetic resonance imaging of the head and neck showed a solid mass measuring approximately 28 mm in diameter with internal heterogeneity and calcification in the deep lobe of the right parotid gland. A positron emission tomography examination showed significant [F-18]-2-fluoro-2-deoxy-D-glucose accumulation associated with the mass in the right parotid gland. The laboratory data were unremarkable except for a slight increase in the level of CEA (10.2 ng/ ml). Fine-needle aspiration (FNA) cytology by ultrasound guidance was performed, and the presence of a high-grade malignant neoplasm, such as carcinosarcoma or carcinoma ex pleomorphic adenoma, was suspected. The patient visited our hospital after receiving a referral, and a right parotidectomy with ipsilateral radical neck dissection was performed. During the surgery, the main trunk of the right facial nerve was found to be involved with the tumor; therefore, it was excised and reconstructed using the peronei nerve. The final histopathological diagnosis was carcinosarcoma ex pleomorphic adenoma of the right parotid gland without nodal metastasis. The patient received radiotherapy (60 Gy) and chemotherapy after surgery. At 17 months of follow-up, no signs of recurrence or metastasis were observed.
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Acta Cytologica 2014;58:419–426 DOI: 10.1159/000365272
Pathological Findings Cytological Findings FNA cytological smears stained with Papanicolaou stain exhibited large cell clusters and singly scattered atypical cells in a necrotic and mucinous background (fig. 1a). Cell clusters showed high cell density and cellular overlapping were observed. In the cluster, glandular structure was partially observed (fig. 1b). These cells had round-shaped nuclei with coarse granular chromatin and the nucleus/cytoplasm (N/C) ratio was high. The singly scattered cells demonstrated marked cellular atypia and pleomorphism, and multinucleated giant cells were also observed (fig. 1c). These cells appeared to be derived from the sarcomatous component or poorly differentiated carcinomatous component; however, none of the cells showed any specific signs of differentiation. In the mucinous stromal component, which exhibited metachromasia on Giemsa staining, isolated sporadic spindle-shaped cells were observed. Clusters of cells with a high N/C ratio were seen around the stromal component (fig. 2). Furthermore, hyaline globules demonstrating metachromasia on Giemsa staining surrounded by roundshaped cells with a high N/C ratio were also observed (fig. 3a, b). These findings, with both epithelial and stromal components, were suggestive of pleomorphic adenoma, although both the epithelium-like cell clusters and singly scattered cells with marked cellular atypia in the necrotic background made us suspect a malignant tumor. The cytological diagnosis of carcinosarcoma ex pleomorphic adenoma was considered with differential diagnosis of carcinoma ex pleomorphic adenoma and undifferentiated carcinoma, but it was impossible to define the histological type. Macroscopic Findings and Histopathology Grossly, the resected specimen revealed a multiloculated, wellcircumscribed mass measuring 25 × 25 × 24 mm in size (fig. 4). The cut surface exhibited a heterogeneous appearance with solid and yellowish-white firm tissue and grayish-white semitransparent tissue. Focal areas of necrosis and calcification were also seen (fig. 4). Microscopically, the tumor was composed of three elements: carcinomatous, sarcomatous and benign pleomorphic adenoma components. The carcinomatous component consisted of undifferentiated carcinoma with necrosis (fig. 5a) and poorly differentiated adenocarcinoma without necrosis (fig. 5b). The tumor cells were small-to-medium in size and variable in shape. The growth patterns were trabecular, alveolar and glandular with large, solid nests with or without central necrosis and stromal mucin deposition. Some tumor nests were surrounded by flattened myoepithelial-like cells (fig. 5c). Abnormal mitoses were occasionally observed. The sarcomatous component was characterized by the presence of chondrosarcoma (fig. 6a) and osteosarcoma. Undifferentiated sarcomatous areas consisting of spindle-shaped cells with marked cellular atypia and multinucleated giant cells were also observed (fig. 6b). No transitional appearance was noted between the carcinomatous and sarcomatous components. Foci of coexisting pleomorphic adenoma were also present, characterized by clusters of benign epithelial and myoepithelial cells with an abundant hyalinized and cartilaginous matrix (fig. 7). The tumor was almost encapsulated, except for focal areas without a fibrous capsule. In these areas, minimal invasion to parotid gland tissue and facial nerve was seen. No invasion to blood or lymphoid vessels was observed, although the facial nerve was involved with the tumor. The
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few cases. In the present case, various components, including the presence of atypical epithelium-like cell clusters and singly scattered atypical cells with stromal components on cytological specimens, led to consideration of the diagnosis of carcinosarcoma ex pleomorphic adenoma.
a
Fig. 1. Cytological findings of tumor. a Epithelium-like cell clusters with high cell density and singly scattered atypical cells in a necrotic mucinous background. Papanicolaou staining. ×100. b Epithelium-like cell cluster with high cell density and partial glandular structure. Papanicolaou staining. ×200. c Singly scattered cells with marked cellular atypism and pleomorphism. Papanicolaou staining. ×200.
b
c
Carcinosarcoma ex Pleomorphic Adenoma
Acta Cytologica 2014;58:419–426 DOI: 10.1159/000365272
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Fig. 2. In the stromal component, which exhibits metachromasia, myoepithelial cells are observed. Clusters of cells with a high N/C ratio are also seen around the stromal component. Giemsa staining. ×200.
a
b
Fig. 3. Hyaline globules are observed within the epithelium-like cells. a Papanicolaou staining. ×200. b Giemsa staining. ×200.
1:100). In part of the carcinomatous area, flattened cells surrounding the tumor nests were positive for α-smooth muscle actin (Dako, 1:50), HHF-35 (Dako, 1:50), p63 (Nichirei, ready to use), calponin and GFAP (Dako, 1:100). The undifferentiated sarcoma cells were focally positive for smooth muscle actin and HHF-35. Both the carcinomatous and sarcomatous components were positive for p53 (Dako, 1:50) and MIB-1 (Dako, 1:50). The MIB-1 labeling index was 10–60%, while p53 was negative and the MIB-1 labeling index was less than 1% in the pleomorphic adenoma component. Both the carcinomatous and sarcomatous components were positive for HMGA2 (Cell Signaling Technology Inc., 1:200; fig. 9) but negative for PLGA1 (Bioss, 1:200). The final pathological diagnosis was carcinosarcoma in pleomorphic adenoma.
Discussion
gland. The cut surface demonstrates a heterogeneous appearance.
surgical margins were tumor free. All available lymph nodes showed no evidence of tumor metastasis. Immunohistochemically, the carcinomatous component showed a positive reaction for cytokeratin AE1/AE3 (Dako, 1:100; fig. 8a) and epithelial membrane antigen (Dako, 1: 50; fig. 8b), while the sarcomatous component was negative for both elements. Both the carcinomatous and sarcomatous components showed some degree of immunoreactivity for vimentin (Dako, 1:50). Some portions of the carcinomatous component were positive for S-100 protein (Dako, 1:500; fig. 8c) and calponin (Dako, 1:50) to varying degrees, depending on the site. The portion of the carcinomatous component with a glandular structure was positive for CEA (Dako,
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Acta Cytologica 2014;58:419–426 DOI: 10.1159/000365272
Carcinosarcoma is defined as a malignant tumor composed of both epithelial (carcinomatous) and mesenchymal (sarcomatous) components. Carcinosarcoma of the salivary gland was first reported by Kirklin et al. [6] in 1951, and approximately 70 cases have been reported since. Carcinosarcoma is an extremely rare tumor, comprising only 0.04–0.16% of all salivary gland tumors and 0.4% of all malignant salivary gland neoplasms [2, 3]. Carcinosarcoma of the salivary gland mainly occurs in major salivary glands (65% of cases in the parotid gland and 22% of cases in the submandibular gland) in elderly patients (mean age at presentation: 58 years) [3]. It is a biologically aggressive and rapidly growing malignant neoplasm with a mean survival time of 2.5–3.6 years [2, 3]. Ishikura /Kawada /Mori /Maegawa /Ohta / Imamura
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Fig. 4. A multiloculated and well-circumscribed mass in the parotid
a
Fig. 5. Histological findings of the resected tumor. Carcinomatous component. a Solid tumor cell nests with necrosis and mucin deposition. HE staining. ×100. b The tumor cells exhibit a glandular structure. HE staining. ×200. c Some tumor nests are surrounded
by myoepithelial-like cells. HE staining. ×100.
a
b
c
b
Carcinosarcoma ex Pleomorphic Adenoma
Acta Cytologica 2014;58:419–426 DOI: 10.1159/000365272
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Fig. 6. Histological findings of the resected tumor. Sarcomatoid component. a Chondrosarcoma. HE staining. ×200. b Spindle-shaped cells with marked cellular atypia and multinucleated giant cells. HE staining. ×200.
Fig. 7. Histological findings of the resected tumor. Pleomorphic adenoma component. Clusters of benign epithelial and myoepithelial cells with a hyalinized and cartilaginous matrix. HE staining. ×40.
a
b
Fig. 8. Immunohistochemical findings of the resected tumor. The
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carcinomatous component is positive for cytokeratin AE1/AE3 (a), epithelial membrane antigen (b) and: S-100 protein (c). ×200.
Carcinosarcoma ex Pleomorphic Adenoma
Acta Cytologica 2014;58:419–426 DOI: 10.1159/000365272
Fig. 9. Carcinomatous and sarcomatous components are positive
for HMGA2. ×200.
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The carcinomatous component is often adenocarcinoma not otherwise specified, undifferentiated carcinoma or squamous cell carcinoma, although adenoid cystic carcinoma, papillary cystic adenocarcinoma and neuroendocrine carcinoma have also been identified [2, 3]. On the other hand, the sarcomatous component is frequently chondrosarcoma; however, fibrosarcoma, osteosarcoma, malignant fibrous histiocytoma, rhabdomyosarcoma and liposarcoma have also been reported [2, 3]. Carcinosarcomas of the salivary gland are usually unencapsulated and infiltrative [2]. Nevertheless, the tumor in the present case was almost fully encapsulated, except for some areas without a fibrous capsule and minimal invasion in the peripheral parotid gland tissue. Most carcinosarcomas of the salivary gland appear to develop de novo, although one third to a half of cases are reported to arise from preexisting adenomas (so-called carcinosarcoma ex pleomorphic adenoma) [4, 5]. Our patient exhibited the histological features of carcinosarcoma with a remnant of benign pleomorphic adenoma. Even in the cytology, benign-looking epithelial and stromal cells suggestive of coexisting benign pleomorphic adenoma were present. In the present case, flattened myoepithelial cells were present around the tumor nests of the carcinomatous component. These cells were negative for p53, and the MIB-1 labeling index was low; therefore, they appeared to be nonneoplastic myoepithelial cells. Similar findings were reported by Harada [7] and Sironi et al. [8]. Harada
[7] suggested that such myoepithelial cells are derived from double-layered ducts of preexisting pleomorphic adenoma and that malignant transformation may occur selectively and multicentrically in inner ductal cells [7]. That is, the disease reflects a state in which only epithelial cells of pleomorphic adenoma exhibit tumorigenesis, although myoepithelial cells remain. In the present case, such findings were observed in the carcinomatous area adjacent to the pleomorphic adenoma component. Making the cytological diagnosis of carcinosarcoma of the salivary gland is difficult due to the rarity of the disease. In the cytology of typical cases of carcinosarcoma, both carcinomatous and sarcomatous elements may appear on the smear, although such cases are, in fact, rare. The components observed on the smear depend on the site of puncture. Furthermore, various cells are often seen in cases of carcinosarcoma ex pleomorphic adenoma, which complicates the cytological diagnosis. To our knowledge, the FNA cytological features of carcinosarcoma of the salivary gland have been described in 4 reports [8–11], and it was possible to evaluate the carcinosarcoma in 2 of the 4 cases [9, 11]. Additionally, 3 of the 4 cases were de novo [8–10], and only 1 case involved pleomorphic adenoma [11]. In the cytology of our case, neoplastic cells with cellular pleomorphism were singly scattered or clustered in a necrotic background. These cells seemed to be derived from poorly differentiated carcinomatous or sarcomatous components. Stroma-like cell clusters with mucin were also observed. Conducting a detailed evaluation of these variable cytological findings enabled us to identify the possibility of carcinosarcoma ex pleomorphic adenoma in the cytology. In the present case, hyaline globules exhibiting metachromasia on Giemsa staining were observed within the epithelium-like cell clusters. The presence of hyaline globules has not been previously reported in carcinosarcoma cases. Although hyaline globules are known to be the most important characteristic of adenoid cystic carcinoma, they can also be seen in other salivary gland tumors, such as polymorphous low-grade adenocarcinoma, basal cell adenoma/adenocarcinoma, epithelial-myoepithelial carcinoma, myoepithelial carcinoma and pleomorphic adenoma [12]. In our case, no adenoid cystic carcinoma components were identified in the histological sections. We suppose that the hyaline globules originated from the pleomorphic adenoma or carcinomatous components. Pleomorphic adenoma and carcinoma ex pleomorphic adenoma have been detected to harbor specific gene
alterations involving PLAG1 on 8q12 or HMGA2 on 12q14–15, and several fusion partners have been reported [13–15], although, as far as we have searched, there has been no report which examined these gene alterations on carcinosarcoma ex pleomorphic adenoma. In the present case, both the carcinomatous and sarcomatous components, as well as the pleomorphic adenomatous component, were positive for HMGA2 but negative for PLGA1 by immunohistochemistry. It was speculated that the carcinosarcoma occurred from a pleomorphic adenoma with an altered HMGA2 gene.
In summary, we herein presented a rare case of carcinosarcoma ex pleomorphic adenoma affecting the right parotid gland of a female patient that was identified based on FNA cytology. Making the cytological diagnosis of carcinosarcoma would be possible by recognizing definitive malignant epithelial and sarcomatous components. When sarcomatous atypical cells are observed, a diagnosis of carcinosarcoma must be taken into consideration in the differential diagnosis, along with undifferentiated carcinoma and sarcomatoid carcinoma ex pleomorphic adenoma.
References
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7 Harada H: Histomorphological investigation regarding to malignant transformation of pleomorphic adenoma (so-called malignant mixed tumor) of the salivary gland origin: special reference to carcinosarcoma. Kurume Med J 2000;47:307–323. 8 Sironi M, Isimbaldi G, Claren R, Delpiano C, Di Nuovo F, Spinelli M: Carcinosarcoma of the parotid gland: cytological, clinicopathological and immunohistochemical study of a case. Pathol Res Pract 2000;196:511–517. 9 Granger JK, Houn HY: Malignant mixed tumor (carcinosarcoma) of parotid gland diagnosed by fine-needle aspiration biopsy. Diagn Cytopathol 1991;7:427–432. 10 de la Torre M, Larsson E: Fine-needle aspiration cytology of carcinosarcoma of the parotid gland: cytohistological and immunohistochemical findings. Diagn Cytopathol 1995;12: 350–353.
Acta Cytologica 2014;58:419–426 DOI: 10.1159/000365272
11 Kim T, Yoon GS, Kim O, Gong G: Fine needle aspiration diagnosis of malignant mixed tumor (carcinosarcoma) arising in pleomorphic adenoma of the salivary gland. A case report. Acta Cytol 1998;42:1027–1031. 12 Klijanienko J: Head and neck: salivary glands; in Orell SR, Sterrett GF, Whitaker G eds): Fine Needle Aspiration Cytology. New York, Elsevier Churchill Livingstone, 2011. 13 Matsuyama A, Hisaoka M, Nagao Y, Hashimoto H: Aberrant PLAG1 expression in pleomorphic adenomas of the salivary gland: a molecular genetic and immunohistochemical study. Virchows Arch 2011;458:583–592. 14 Bahrami A, Dalton JD, Shivakumar B, Krane JF: PLAG1 alteration in carcinoma ex pleomorphic adenoma: immunohistochemical and fluorescence in situ hybridization studies of 22 cases. Head Neck Pathol 2012; 6: 328– 335. 15 Stenman G: Fusion oncogenes in salivary gland tumors: molecular and clinical consequences. Head Neck Pathol. 2013; 7(suppl 1): S12–S19.
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1 Barnes L, Eveson JW, Reichart, Sidransky D (eds): World Health Organization Classification of Tumors: Pathology and Genetics of Head and Neck Tumors. Lyon, IARC, 2005. 2 Ellis GL, Auclair PL (eds): Atlas of Tumor Pathology: Tumors of the Salivary Gland. Washington, Armed Forces Institute of Pathology, 2008. 3 Gnepp DR: Malignant mixed tumor of the salivary glands: a review. Pathol Annu 1993; 28:279–328. 4 Kwon MY, Gu M: True malignant mixed tumor (carcinosarcoma) of parotid gland with unusual mesenchymal component: a case report and review of the literature. Arch Pathol Lab Med 2001;125:812–815. 5 Staffieri C, Marioni G, Ferraro SM, Marino F, Staffieri A: Carcinosarcoma de novo of the salivary gland. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:e35–e40. 6 Kirklin JW, McDonald JR, Harrington SW, New GB: Parotid tumors: histopathology, clinical behavior and end results. Surg Gynecol Obstet 1951;92:721–733.
Received: February 10, 2014 Accepted after revision: June 6, 2014 Published online: August 14, 2014
Cytological Features of Carcinosarcoma ex Pleomorphic Adenoma of the Parotid Gland: A Case Report Naoyo Ishikura a Takako Kawada b Masaki Mori c Hideki Maegawa c Makoto Ohta d Yoshiaki Imamura c a
Department of Pathology and Laboratory Medicine, Nagoya University Hospital, Nagoya, b Department of Cytopathology, Maizuru Kyosai Hospital, Kyoto, c Division of Surgical Pathology, University of Fukui Hospital, and d Department of Pathology, Fukui Red Cross Hospital, Fukui, Japan
Established Facts • Carcinosarcoma of the salivary gland is an extremely rare tumor composed of both carcinomatous and sarcomatous components. In cytology, both components may appear on the smears. • One third to a half of cases arise from a preexisting pleomorphic adenoma.
Novel Insights • Hyaline globules showing metachromasia on Giemsa staining, as observed in this case, have not been previously reported in other carcinosarcoma cases. • This is the second case report describing the cytological findings of carcinosarcoma ex pleomorphic adenoma of the salivary gland.
Abstract Background: Carcinosarcoma of the salivary gland is an extremely rare tumor composed of carcinomatous and sarcomatoid components. This report describes the cytological and pathological findings of a case of carcinosarcoma ex pleomorphic adenoma arising in the right parotid gland.
© 2014 S. Karger AG, Basel 0001–5547/14/0584–0419$39.50/0 E-Mail [email protected] www.karger.com/acy
Case: A 47-year-old female visited a hospital with swelling of the right parotid region, slight pain and facial palsy. Fine-needle aspiration smears showed both clustered epithelium-like cells and singly scattered cells in a necrotic background. The cells, especially the latter, exhibited significant cellular pleomorphism and had irregularly shaped nuclei. Myxoid stromalike cell clusters without cellular atypism were also seen. The right parotid gland was resected, and the tumor tissue was histologically diagnosed as carcinosarcoma ex pleomorphic adenoma. Conclusion: The cytological findings of carcinosarcoma ex pleomorphic adenoma have been reported in very
Correspondence to: Dr. Naoyo Ishikura Department of Pathology and Laboratory Medicine, Nagoya University Hospital 65 Tsurumai-cho, Showa-ku Nagoya 466-8560 (Japan) E-Mail ishikuranao @ med.nagoya-u.ac.jp
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Key Words Carcinosarcoma · Pleomorphic adenoma · Salivary gland neoplasms · Fine-needle aspiration cytology
© 2014 S. Karger AG, Basel
Introduction
Carcinosarcoma is a high-grade malignant neoplasm composed of a mixture of both carcinomatous and sarcomatous components [1]. Carcinosarcoma of the salivary gland is an extremely rare tumor, comprising only 0.04– 0.16% of all salivary gland tumors and 0.4% of all malignant salivary gland neoplasms [2, 3]. It usually arises in the major salivary glands in elderly patients and causes swelling of the salivary glands with pain and facial palsy [2, 3]. Most carcinosarcomas develop de novo; however, one third to a half of cases occur in association with benign pleomorphic adenoma [4, 5]. This report describes the cytological and histological findings of a case of carcinosarcoma ex pleomorphic adenoma of the right parotid gland. Case Report A 47-year-old female visited a neighboring hospital with swelling of the right parotid gland of 5-month’s duration. She also complained of mild pain and facial palsy. Her family history and past history were unremarkable. Ultrasonography, computerized tomography and magnetic resonance imaging of the head and neck showed a solid mass measuring approximately 28 mm in diameter with internal heterogeneity and calcification in the deep lobe of the right parotid gland. A positron emission tomography examination showed significant [F-18]-2-fluoro-2-deoxy-D-glucose accumulation associated with the mass in the right parotid gland. The laboratory data were unremarkable except for a slight increase in the level of CEA (10.2 ng/ ml). Fine-needle aspiration (FNA) cytology by ultrasound guidance was performed, and the presence of a high-grade malignant neoplasm, such as carcinosarcoma or carcinoma ex pleomorphic adenoma, was suspected. The patient visited our hospital after receiving a referral, and a right parotidectomy with ipsilateral radical neck dissection was performed. During the surgery, the main trunk of the right facial nerve was found to be involved with the tumor; therefore, it was excised and reconstructed using the peronei nerve. The final histopathological diagnosis was carcinosarcoma ex pleomorphic adenoma of the right parotid gland without nodal metastasis. The patient received radiotherapy (60 Gy) and chemotherapy after surgery. At 17 months of follow-up, no signs of recurrence or metastasis were observed.
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Acta Cytologica 2014;58:419–426 DOI: 10.1159/000365272
Pathological Findings Cytological Findings FNA cytological smears stained with Papanicolaou stain exhibited large cell clusters and singly scattered atypical cells in a necrotic and mucinous background (fig. 1a). Cell clusters showed high cell density and cellular overlapping were observed. In the cluster, glandular structure was partially observed (fig. 1b). These cells had round-shaped nuclei with coarse granular chromatin and the nucleus/cytoplasm (N/C) ratio was high. The singly scattered cells demonstrated marked cellular atypia and pleomorphism, and multinucleated giant cells were also observed (fig. 1c). These cells appeared to be derived from the sarcomatous component or poorly differentiated carcinomatous component; however, none of the cells showed any specific signs of differentiation. In the mucinous stromal component, which exhibited metachromasia on Giemsa staining, isolated sporadic spindle-shaped cells were observed. Clusters of cells with a high N/C ratio were seen around the stromal component (fig. 2). Furthermore, hyaline globules demonstrating metachromasia on Giemsa staining surrounded by roundshaped cells with a high N/C ratio were also observed (fig. 3a, b). These findings, with both epithelial and stromal components, were suggestive of pleomorphic adenoma, although both the epithelium-like cell clusters and singly scattered cells with marked cellular atypia in the necrotic background made us suspect a malignant tumor. The cytological diagnosis of carcinosarcoma ex pleomorphic adenoma was considered with differential diagnosis of carcinoma ex pleomorphic adenoma and undifferentiated carcinoma, but it was impossible to define the histological type. Macroscopic Findings and Histopathology Grossly, the resected specimen revealed a multiloculated, wellcircumscribed mass measuring 25 × 25 × 24 mm in size (fig. 4). The cut surface exhibited a heterogeneous appearance with solid and yellowish-white firm tissue and grayish-white semitransparent tissue. Focal areas of necrosis and calcification were also seen (fig. 4). Microscopically, the tumor was composed of three elements: carcinomatous, sarcomatous and benign pleomorphic adenoma components. The carcinomatous component consisted of undifferentiated carcinoma with necrosis (fig. 5a) and poorly differentiated adenocarcinoma without necrosis (fig. 5b). The tumor cells were small-to-medium in size and variable in shape. The growth patterns were trabecular, alveolar and glandular with large, solid nests with or without central necrosis and stromal mucin deposition. Some tumor nests were surrounded by flattened myoepithelial-like cells (fig. 5c). Abnormal mitoses were occasionally observed. The sarcomatous component was characterized by the presence of chondrosarcoma (fig. 6a) and osteosarcoma. Undifferentiated sarcomatous areas consisting of spindle-shaped cells with marked cellular atypia and multinucleated giant cells were also observed (fig. 6b). No transitional appearance was noted between the carcinomatous and sarcomatous components. Foci of coexisting pleomorphic adenoma were also present, characterized by clusters of benign epithelial and myoepithelial cells with an abundant hyalinized and cartilaginous matrix (fig. 7). The tumor was almost encapsulated, except for focal areas without a fibrous capsule. In these areas, minimal invasion to parotid gland tissue and facial nerve was seen. No invasion to blood or lymphoid vessels was observed, although the facial nerve was involved with the tumor. The
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few cases. In the present case, various components, including the presence of atypical epithelium-like cell clusters and singly scattered atypical cells with stromal components on cytological specimens, led to consideration of the diagnosis of carcinosarcoma ex pleomorphic adenoma.
a
Fig. 1. Cytological findings of tumor. a Epithelium-like cell clusters with high cell density and singly scattered atypical cells in a necrotic mucinous background. Papanicolaou staining. ×100. b Epithelium-like cell cluster with high cell density and partial glandular structure. Papanicolaou staining. ×200. c Singly scattered cells with marked cellular atypism and pleomorphism. Papanicolaou staining. ×200.
b
c
Carcinosarcoma ex Pleomorphic Adenoma
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Fig. 2. In the stromal component, which exhibits metachromasia, myoepithelial cells are observed. Clusters of cells with a high N/C ratio are also seen around the stromal component. Giemsa staining. ×200.
a
b
Fig. 3. Hyaline globules are observed within the epithelium-like cells. a Papanicolaou staining. ×200. b Giemsa staining. ×200.
1:100). In part of the carcinomatous area, flattened cells surrounding the tumor nests were positive for α-smooth muscle actin (Dako, 1:50), HHF-35 (Dako, 1:50), p63 (Nichirei, ready to use), calponin and GFAP (Dako, 1:100). The undifferentiated sarcoma cells were focally positive for smooth muscle actin and HHF-35. Both the carcinomatous and sarcomatous components were positive for p53 (Dako, 1:50) and MIB-1 (Dako, 1:50). The MIB-1 labeling index was 10–60%, while p53 was negative and the MIB-1 labeling index was less than 1% in the pleomorphic adenoma component. Both the carcinomatous and sarcomatous components were positive for HMGA2 (Cell Signaling Technology Inc., 1:200; fig. 9) but negative for PLGA1 (Bioss, 1:200). The final pathological diagnosis was carcinosarcoma in pleomorphic adenoma.
Discussion
gland. The cut surface demonstrates a heterogeneous appearance.
surgical margins were tumor free. All available lymph nodes showed no evidence of tumor metastasis. Immunohistochemically, the carcinomatous component showed a positive reaction for cytokeratin AE1/AE3 (Dako, 1:100; fig. 8a) and epithelial membrane antigen (Dako, 1: 50; fig. 8b), while the sarcomatous component was negative for both elements. Both the carcinomatous and sarcomatous components showed some degree of immunoreactivity for vimentin (Dako, 1:50). Some portions of the carcinomatous component were positive for S-100 protein (Dako, 1:500; fig. 8c) and calponin (Dako, 1:50) to varying degrees, depending on the site. The portion of the carcinomatous component with a glandular structure was positive for CEA (Dako,
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Carcinosarcoma is defined as a malignant tumor composed of both epithelial (carcinomatous) and mesenchymal (sarcomatous) components. Carcinosarcoma of the salivary gland was first reported by Kirklin et al. [6] in 1951, and approximately 70 cases have been reported since. Carcinosarcoma is an extremely rare tumor, comprising only 0.04–0.16% of all salivary gland tumors and 0.4% of all malignant salivary gland neoplasms [2, 3]. Carcinosarcoma of the salivary gland mainly occurs in major salivary glands (65% of cases in the parotid gland and 22% of cases in the submandibular gland) in elderly patients (mean age at presentation: 58 years) [3]. It is a biologically aggressive and rapidly growing malignant neoplasm with a mean survival time of 2.5–3.6 years [2, 3]. Ishikura /Kawada /Mori /Maegawa /Ohta / Imamura
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Fig. 4. A multiloculated and well-circumscribed mass in the parotid
a
Fig. 5. Histological findings of the resected tumor. Carcinomatous component. a Solid tumor cell nests with necrosis and mucin deposition. HE staining. ×100. b The tumor cells exhibit a glandular structure. HE staining. ×200. c Some tumor nests are surrounded
by myoepithelial-like cells. HE staining. ×100.
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b
c
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Carcinosarcoma ex Pleomorphic Adenoma
Acta Cytologica 2014;58:419–426 DOI: 10.1159/000365272
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Fig. 6. Histological findings of the resected tumor. Sarcomatoid component. a Chondrosarcoma. HE staining. ×200. b Spindle-shaped cells with marked cellular atypia and multinucleated giant cells. HE staining. ×200.
Fig. 7. Histological findings of the resected tumor. Pleomorphic adenoma component. Clusters of benign epithelial and myoepithelial cells with a hyalinized and cartilaginous matrix. HE staining. ×40.
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b
Fig. 8. Immunohistochemical findings of the resected tumor. The
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Ishikura /Kawada /Mori /Maegawa /Ohta / Imamura
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carcinomatous component is positive for cytokeratin AE1/AE3 (a), epithelial membrane antigen (b) and: S-100 protein (c). ×200.
Carcinosarcoma ex Pleomorphic Adenoma
Acta Cytologica 2014;58:419–426 DOI: 10.1159/000365272
Fig. 9. Carcinomatous and sarcomatous components are positive
for HMGA2. ×200.
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The carcinomatous component is often adenocarcinoma not otherwise specified, undifferentiated carcinoma or squamous cell carcinoma, although adenoid cystic carcinoma, papillary cystic adenocarcinoma and neuroendocrine carcinoma have also been identified [2, 3]. On the other hand, the sarcomatous component is frequently chondrosarcoma; however, fibrosarcoma, osteosarcoma, malignant fibrous histiocytoma, rhabdomyosarcoma and liposarcoma have also been reported [2, 3]. Carcinosarcomas of the salivary gland are usually unencapsulated and infiltrative [2]. Nevertheless, the tumor in the present case was almost fully encapsulated, except for some areas without a fibrous capsule and minimal invasion in the peripheral parotid gland tissue. Most carcinosarcomas of the salivary gland appear to develop de novo, although one third to a half of cases are reported to arise from preexisting adenomas (so-called carcinosarcoma ex pleomorphic adenoma) [4, 5]. Our patient exhibited the histological features of carcinosarcoma with a remnant of benign pleomorphic adenoma. Even in the cytology, benign-looking epithelial and stromal cells suggestive of coexisting benign pleomorphic adenoma were present. In the present case, flattened myoepithelial cells were present around the tumor nests of the carcinomatous component. These cells were negative for p53, and the MIB-1 labeling index was low; therefore, they appeared to be nonneoplastic myoepithelial cells. Similar findings were reported by Harada [7] and Sironi et al. [8]. Harada
[7] suggested that such myoepithelial cells are derived from double-layered ducts of preexisting pleomorphic adenoma and that malignant transformation may occur selectively and multicentrically in inner ductal cells [7]. That is, the disease reflects a state in which only epithelial cells of pleomorphic adenoma exhibit tumorigenesis, although myoepithelial cells remain. In the present case, such findings were observed in the carcinomatous area adjacent to the pleomorphic adenoma component. Making the cytological diagnosis of carcinosarcoma of the salivary gland is difficult due to the rarity of the disease. In the cytology of typical cases of carcinosarcoma, both carcinomatous and sarcomatous elements may appear on the smear, although such cases are, in fact, rare. The components observed on the smear depend on the site of puncture. Furthermore, various cells are often seen in cases of carcinosarcoma ex pleomorphic adenoma, which complicates the cytological diagnosis. To our knowledge, the FNA cytological features of carcinosarcoma of the salivary gland have been described in 4 reports [8–11], and it was possible to evaluate the carcinosarcoma in 2 of the 4 cases [9, 11]. Additionally, 3 of the 4 cases were de novo [8–10], and only 1 case involved pleomorphic adenoma [11]. In the cytology of our case, neoplastic cells with cellular pleomorphism were singly scattered or clustered in a necrotic background. These cells seemed to be derived from poorly differentiated carcinomatous or sarcomatous components. Stroma-like cell clusters with mucin were also observed. Conducting a detailed evaluation of these variable cytological findings enabled us to identify the possibility of carcinosarcoma ex pleomorphic adenoma in the cytology. In the present case, hyaline globules exhibiting metachromasia on Giemsa staining were observed within the epithelium-like cell clusters. The presence of hyaline globules has not been previously reported in carcinosarcoma cases. Although hyaline globules are known to be the most important characteristic of adenoid cystic carcinoma, they can also be seen in other salivary gland tumors, such as polymorphous low-grade adenocarcinoma, basal cell adenoma/adenocarcinoma, epithelial-myoepithelial carcinoma, myoepithelial carcinoma and pleomorphic adenoma [12]. In our case, no adenoid cystic carcinoma components were identified in the histological sections. We suppose that the hyaline globules originated from the pleomorphic adenoma or carcinomatous components. Pleomorphic adenoma and carcinoma ex pleomorphic adenoma have been detected to harbor specific gene
alterations involving PLAG1 on 8q12 or HMGA2 on 12q14–15, and several fusion partners have been reported [13–15], although, as far as we have searched, there has been no report which examined these gene alterations on carcinosarcoma ex pleomorphic adenoma. In the present case, both the carcinomatous and sarcomatous components, as well as the pleomorphic adenomatous component, were positive for HMGA2 but negative for PLGA1 by immunohistochemistry. It was speculated that the carcinosarcoma occurred from a pleomorphic adenoma with an altered HMGA2 gene.
In summary, we herein presented a rare case of carcinosarcoma ex pleomorphic adenoma affecting the right parotid gland of a female patient that was identified based on FNA cytology. Making the cytological diagnosis of carcinosarcoma would be possible by recognizing definitive malignant epithelial and sarcomatous components. When sarcomatous atypical cells are observed, a diagnosis of carcinosarcoma must be taken into consideration in the differential diagnosis, along with undifferentiated carcinoma and sarcomatoid carcinoma ex pleomorphic adenoma.
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Acta Cytologica 2014;58:419–426 DOI: 10.1159/000365272
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