520037
research-article2014
IJSXXX10.1177/1066896913520037International Journal of Surgical PathologyZannella et al
Case Report
Peritoneal Malignant Mesothelioma Metastatic to Supraclavicular Lymph Nodes
International Journal of Surgical Pathology 2014, Vol. 22(6) 552–554 © The Author(s) 2014 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1066896913520037 ijs.sagepub.com
Stefano Zannella, MD1,2, Maria Adele Testi, DSc3, Giorgio Cattoretti, MD1,2, Giuseppe Pelosi, MD3,4, and Nicola Zucchini, MD1,2
Abstract Distinguishing between malignant mesothelioma and reactive mesothelial hyperplasia is often inestimable, but may be a challenging gauntlet for pathologists. A 62-year-old man underwent appendectomy after the identification of a peritoneal mass and the histological examination showed mesothelial proliferation along the appendix surface with no clear images of infiltration. After a few months the patient developed mediastinal and supraclavicular lymphadenopathies, and a nodal biopsy showed mesothelial cell proliferation invading lymphatic sinuses, consistent with the cells seen in the abdominal cavity. Since overt morphologic criteria for malignancy were lacking and reactive mesothelial cell deposits have been documented in lymph nodes, a molecular investigation of the CDKN2A (henceforth simply p16) gene status via fluorescence in situ hybridization was performed, which showed homozygous deletion in 100% tumor cells. These data ruled out the hypothesis of reactive mesothelial cells inclusion in lymph nodes, thus confirming the diagnosis of epithelioid malignant mesothelioma. Keywords mesothelioma, peritoneal mesothelioma, metastatic mesothelioma, mesothelial hyperplasia, CDKN2A
Introduction Distinguishing malignant mesothelioma (MM) from reactive mesothelial cell hyperplasia may prove to be a challenge for the pathologists. However, because of differences in therapy and prognostic implications, splitting these entities is crucial for the proper clinical management of patients. Morphologic criteria like stromal or adipose tissue infiltration may assist in the differential diagnosis, but this feature may be deceptive in the peritoneal cavity and immunohistochemistry for several markers, such as GLUT-1 or IMP3 may not be specific or sensitive enough or may not be tested in the peritoneum yet. Recently, attention has been paid to the diagnostic role of p16 homozygous deletion by fluorescence in situ hybridization (FISH) analysis also in peritoneal location, but additional observations of single case report are clinically warranted thereby justifying an integrated, multidisciplinary approach to address these cases properly.1
Case Report A 62-year-old patient was admitted to the hospital with acute abdominal pain. Past history included ischemic cardiomiopathy, hypertension, dyslipidemia, varicose
phlebopathy, coronary angioplasty, stenting, and hernioplastic surgery. Computed tomography scan showed an ill-defined peritoneal mass. At surgery, diffuse peritonitis was found with adhesions between urinary bladder, appendix, and ileum, which were resolved along with diagnostic appendectomy. Since then, the patient developed progressive ascites with serum increase of inflammatory markers. A few months later, the patient underwent a control thoracic-abdominal computed tomography scan, which exhibited supraclavicular, axillary, paraesophageal, and paratracheal lymphadenopathies, raising suspicions of neoplastic or infectious disease. A left supraclavicular lymph node biopsy was then performed for histological examination.
1
Ospedale San Gerardo, Monza, Italy Università degli Studi di Milano-Bicocca, Milan, Italy 3 Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy 4 Università degli Studi di Milano, Milan, Italy 2
Corresponding Author: Stefano Zannella, Ospedale San Gerardo, Via Pergolesi, 33, 20900 Monza (MB), Italy. Email: [email protected]
553
Zannella et al
Figure 1. Mesothelial cells population localized all along the appendix serosal surface (see insert).
Figure 2. The same cells are found both in subcapsular and medullary sinuses of a laterocervical lymph node.
Histopathology Examination In an intense and widespread chronic inflammation with fibrin deposits, which was seen to involve the peritoneal layer of the appendix, there was a bland-appearing epithelioid cell proliferation with foamy cytoplasm, large nuclei, inconspicuous nucleoli and, sometimes, binucleation (Figure 1). This population displayed a strong immunoreactivity for cytokeratin pool AE1-AE3, the mesothelial-related marker Wilms tumor 1 (WT1) and calretinin. Ki-67 labeling index was moderately elevated (20%), but there was no clear evidence of invasion or desmoplastic reaction to suggest malignant mesothelioma. Supraclavicular lymph nodes were engulfed by the same epithelioid cells as those seen in the appendix peritoneum, filling subcapsular and medullary lymphatic sinuses. These elements, however, showed a higher degree of nuclear pleomorphism with atypical mitoses, eosinophilic cytoplasm, centrally located or peripheral round nuclei, coarse chromatin, and prominent nucleoli (Figure 2). Cytokeratin pool AE1-AE3 and WT1 intensely stained these cells, which also presented a dim reactivity for calretinin. Other markers (cytokeratin 20, CDX2, desmin, ALK protein, S100 protein, CD68R [PGM1], CD23, CD31, and CD30) were negative. Ki-67 labeling index was higher (30% to 40%) than previously recorded. Fluorescence in situ hybridization analysis for the assessment of the CDKN2A (9p21) gene status (Vysis/ Abbott, Abbott Park, IL) encoding for the p16 protein showed homozygous deletion in 100% examined cells in both the appendix and lymph node samples (Figure 3). The patient underwent chemotherapy and he is alive with disease at 10-month follow-up.
Figure 3. Fluorescence in situ hybridization analysis for p16 deletion demonstrating the presence of centromere signals (green spots) only, whereas the specific p16 gene signals (red spots) are lacking in all tumor cells (few cell nuclei with conserved red signals correspond to normal control cells).
Discussion Because of the clinical presentation of the patient, characterized by ascitic effusion and lymphadenopathies, the crucial point at the beginning was to determinate whether the mesothelial cells lining the appendix were malignant or reactive. The latter condition often mimics malignant mesothelioma and could be associated with infections, collagen vascular diseases, drug reactions, surgery, trauma, and nonspecific inflammation. Since the appendix specimen did not display adipose tissue infiltration by mesothelial cells, which showed only mild atypia, the morphologic criteria to diagnose MM were not completely fulfilled.
554 The occurrence of the same cells in the later-biopsied supraclavicular lymph node raised concerns about diagnosis of malignancy, even if hyperplastic mesothelial cell (HMC) inclusions in lymph nodes have been reported to associate with reactive mesothelium, serosal effusion or chronic inflammatory conditions. HMC in lymph nodes is a peculiar condition which pathologists must be aware of, where nonneoplastic mesothelial cells are described to fill nodal sinuses and lymphatic vessels. The first description of HMC in lymph nodes dates back to Brooks et al2 in 1990, who reported on 2 cases with pleural effusion of neoplastic and infectious origin. Other cases of abdominal, pelvic, and cervical nodal localizations were successively reported, in association with both neoplastic and non-neoplastic conditions, mostly concurrent with serosal effusion.3-5 Suárez Vilela and Izquierdo García5 theorized that HMCs could reach lymph nodes via lymphatic vessels and through stomas of the parietal serosa. This hypothesis seemed to be confirmed by the finding, in the cases reported above, of HMCs in extranodal lymphatic vessels. The differential diagnosis with MM metastasis could be very challenging and the only way to avoid misdiagnosis, thus preventing unnecessary therapies, is the correlation with the clinical data aimed to exclude a primary neoplasm and an adequate follow-up. Nowadays, a fundamental diagnostic tool is represented by the FISH assessment of the CDKN2A gene status encoding p16 protein, which is known to play an important role in the development of several tumor types by regulating cell cycle. Since p16 is a tumor suppressor gene, the loss of both of the alleles is necessary for the development of a malignant process. Chung et al6 found that 33 out of 54 (61%) MM showed CDKN2A homozygous deletion, while none of reactive mesothelial cell proliferations showed deletion. Similarly, Wu et al7 showed that this gene alteration was seen in 86% of 50 MM cases but in none of 10 fibrous pleuritis cases, so confirming 100% specificity of the assay. Moreover, homozygous p16 deletion is reported to be a poor prognostic factor in pleural and peritoneal epithelioid mesothelioma.8,9 These data emphasize the opportunity to look for p16 deletion not only to differentiate between MM and nonneoplastic mesothelial proliferation but also to provide patients with a prognostic factor. In our case, FISH analysis, performed in both anatomical sites, displayed homozygous deletion in 100% mesothelial cells thereby enabling diagnosis of MM with nodal metastases and potential poor prognosis. A similar supraclavicular localization of a peritoneal malignant mesothelioma was first described by Sussman and Rosai10 in 1990, who presented a series of cases in which the mesothelioma diagnosis was made on metastatic nodes, also supporting the view that peritoneal MM were more prone to lymph node metastases than their
International Journal of Surgical Pathology 22(6) pleural counterpart. In one of these cases, a few months after an initial histologic diagnosis of hemangiopericytoma on a supraclavicular mass of a 56-year-old man, a laparotomy revealed a diffuse peritoneal seeding by MM. In the present case, FISH analysis in association with the worsening of the patient’s clinical situation were in keeping with the diagnosis of MM, while morphology and immunohistochemistry were not fully conclusive for malignancy. Therefore, such a test should be introduced in the diagnostic workup in the event of equivocal mesothelial cell proliferation. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Husain AN, Colby T, Ordonez N, et al. Guidelines for pathologic diagnosis of malignant mesothelioma. 2012 update of the consensus statement from the International Mesothelioma Interest Group. Arch Pathol Lab Med. 2013;137:647-667. 2. Brooks JS, LiVolsi VA, Pietra GG. Mesothelial cell inclusions in mediastinal lymph nodes mimicking metastatic carcinoma. Am J Clin Pathol. 1990;93:741-748. 3. Argani P, Rosai J. Hyperplastic mesothelial cells in lymph nodes: report of six cases of a benign process that can simulate metastatic involvement by mesothelioma or carcinoma. Hum Pathol. 1998;29:339-346. 4. Isotalo PA, Veinot JP, Jabi M. Hyperplastic mesothelial cells in mediastinal lymph node sinuses with extranodal lymphatic involvement. Arch Pathol Lab Med. 2000;124:609-613. 5. Suárez Vilela D, Izquierdo García FM. Hyperplastic mesothelial cells in mediastinal lymph node sinuses. Arch Pathol Lab Med. 2000;124:1749. 6. Chung CT, Santos Gda C, Hwang DM, et al. FISH assay development for the detection of p16/CDKN2A deletion in malignant pleural mesothelioma. J Clin Pathol. 2010;63:630-634. 7. Wu D, Hiroshima K, Matsumoto S, et al. Diagnostic usefulness of p16/CDKN2A FISH in distinguishing between sarcomatoid mesothelioma and fibrous pleuritis. Am J Clin Pathol. 2013;139:39-46. 8. Dacic S, Kothmaier H, Land S, et al. Prognostic significance of p16/cdkn2a loss in pleural malignant mesotheliomas. Virchows Arch. 2008;453:627-635. 9. Borczuk AC, Taub RN, Hesdorffer M, et al. P16 loss and mitotic activity predict poor survival in patients with peritoneal malignant mesothelioma. Clin Cancer Res. 2005;11:3303-3308. 10. Sussman J, Rosai J. Lymph node metastasis as the initial manifestation of malignant mesothelioma. Report of six cases. Am J Surg Pathol. 1990;14:819-828.
research-article2014
IJSXXX10.1177/1066896913520037International Journal of Surgical PathologyZannella et al
Case Report
Peritoneal Malignant Mesothelioma Metastatic to Supraclavicular Lymph Nodes
International Journal of Surgical Pathology 2014, Vol. 22(6) 552–554 © The Author(s) 2014 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1066896913520037 ijs.sagepub.com
Stefano Zannella, MD1,2, Maria Adele Testi, DSc3, Giorgio Cattoretti, MD1,2, Giuseppe Pelosi, MD3,4, and Nicola Zucchini, MD1,2
Abstract Distinguishing between malignant mesothelioma and reactive mesothelial hyperplasia is often inestimable, but may be a challenging gauntlet for pathologists. A 62-year-old man underwent appendectomy after the identification of a peritoneal mass and the histological examination showed mesothelial proliferation along the appendix surface with no clear images of infiltration. After a few months the patient developed mediastinal and supraclavicular lymphadenopathies, and a nodal biopsy showed mesothelial cell proliferation invading lymphatic sinuses, consistent with the cells seen in the abdominal cavity. Since overt morphologic criteria for malignancy were lacking and reactive mesothelial cell deposits have been documented in lymph nodes, a molecular investigation of the CDKN2A (henceforth simply p16) gene status via fluorescence in situ hybridization was performed, which showed homozygous deletion in 100% tumor cells. These data ruled out the hypothesis of reactive mesothelial cells inclusion in lymph nodes, thus confirming the diagnosis of epithelioid malignant mesothelioma. Keywords mesothelioma, peritoneal mesothelioma, metastatic mesothelioma, mesothelial hyperplasia, CDKN2A
Introduction Distinguishing malignant mesothelioma (MM) from reactive mesothelial cell hyperplasia may prove to be a challenge for the pathologists. However, because of differences in therapy and prognostic implications, splitting these entities is crucial for the proper clinical management of patients. Morphologic criteria like stromal or adipose tissue infiltration may assist in the differential diagnosis, but this feature may be deceptive in the peritoneal cavity and immunohistochemistry for several markers, such as GLUT-1 or IMP3 may not be specific or sensitive enough or may not be tested in the peritoneum yet. Recently, attention has been paid to the diagnostic role of p16 homozygous deletion by fluorescence in situ hybridization (FISH) analysis also in peritoneal location, but additional observations of single case report are clinically warranted thereby justifying an integrated, multidisciplinary approach to address these cases properly.1
Case Report A 62-year-old patient was admitted to the hospital with acute abdominal pain. Past history included ischemic cardiomiopathy, hypertension, dyslipidemia, varicose
phlebopathy, coronary angioplasty, stenting, and hernioplastic surgery. Computed tomography scan showed an ill-defined peritoneal mass. At surgery, diffuse peritonitis was found with adhesions between urinary bladder, appendix, and ileum, which were resolved along with diagnostic appendectomy. Since then, the patient developed progressive ascites with serum increase of inflammatory markers. A few months later, the patient underwent a control thoracic-abdominal computed tomography scan, which exhibited supraclavicular, axillary, paraesophageal, and paratracheal lymphadenopathies, raising suspicions of neoplastic or infectious disease. A left supraclavicular lymph node biopsy was then performed for histological examination.
1
Ospedale San Gerardo, Monza, Italy Università degli Studi di Milano-Bicocca, Milan, Italy 3 Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy 4 Università degli Studi di Milano, Milan, Italy 2
Corresponding Author: Stefano Zannella, Ospedale San Gerardo, Via Pergolesi, 33, 20900 Monza (MB), Italy. Email: [email protected]
553
Zannella et al
Figure 1. Mesothelial cells population localized all along the appendix serosal surface (see insert).
Figure 2. The same cells are found both in subcapsular and medullary sinuses of a laterocervical lymph node.
Histopathology Examination In an intense and widespread chronic inflammation with fibrin deposits, which was seen to involve the peritoneal layer of the appendix, there was a bland-appearing epithelioid cell proliferation with foamy cytoplasm, large nuclei, inconspicuous nucleoli and, sometimes, binucleation (Figure 1). This population displayed a strong immunoreactivity for cytokeratin pool AE1-AE3, the mesothelial-related marker Wilms tumor 1 (WT1) and calretinin. Ki-67 labeling index was moderately elevated (20%), but there was no clear evidence of invasion or desmoplastic reaction to suggest malignant mesothelioma. Supraclavicular lymph nodes were engulfed by the same epithelioid cells as those seen in the appendix peritoneum, filling subcapsular and medullary lymphatic sinuses. These elements, however, showed a higher degree of nuclear pleomorphism with atypical mitoses, eosinophilic cytoplasm, centrally located or peripheral round nuclei, coarse chromatin, and prominent nucleoli (Figure 2). Cytokeratin pool AE1-AE3 and WT1 intensely stained these cells, which also presented a dim reactivity for calretinin. Other markers (cytokeratin 20, CDX2, desmin, ALK protein, S100 protein, CD68R [PGM1], CD23, CD31, and CD30) were negative. Ki-67 labeling index was higher (30% to 40%) than previously recorded. Fluorescence in situ hybridization analysis for the assessment of the CDKN2A (9p21) gene status (Vysis/ Abbott, Abbott Park, IL) encoding for the p16 protein showed homozygous deletion in 100% examined cells in both the appendix and lymph node samples (Figure 3). The patient underwent chemotherapy and he is alive with disease at 10-month follow-up.
Figure 3. Fluorescence in situ hybridization analysis for p16 deletion demonstrating the presence of centromere signals (green spots) only, whereas the specific p16 gene signals (red spots) are lacking in all tumor cells (few cell nuclei with conserved red signals correspond to normal control cells).
Discussion Because of the clinical presentation of the patient, characterized by ascitic effusion and lymphadenopathies, the crucial point at the beginning was to determinate whether the mesothelial cells lining the appendix were malignant or reactive. The latter condition often mimics malignant mesothelioma and could be associated with infections, collagen vascular diseases, drug reactions, surgery, trauma, and nonspecific inflammation. Since the appendix specimen did not display adipose tissue infiltration by mesothelial cells, which showed only mild atypia, the morphologic criteria to diagnose MM were not completely fulfilled.
554 The occurrence of the same cells in the later-biopsied supraclavicular lymph node raised concerns about diagnosis of malignancy, even if hyperplastic mesothelial cell (HMC) inclusions in lymph nodes have been reported to associate with reactive mesothelium, serosal effusion or chronic inflammatory conditions. HMC in lymph nodes is a peculiar condition which pathologists must be aware of, where nonneoplastic mesothelial cells are described to fill nodal sinuses and lymphatic vessels. The first description of HMC in lymph nodes dates back to Brooks et al2 in 1990, who reported on 2 cases with pleural effusion of neoplastic and infectious origin. Other cases of abdominal, pelvic, and cervical nodal localizations were successively reported, in association with both neoplastic and non-neoplastic conditions, mostly concurrent with serosal effusion.3-5 Suárez Vilela and Izquierdo García5 theorized that HMCs could reach lymph nodes via lymphatic vessels and through stomas of the parietal serosa. This hypothesis seemed to be confirmed by the finding, in the cases reported above, of HMCs in extranodal lymphatic vessels. The differential diagnosis with MM metastasis could be very challenging and the only way to avoid misdiagnosis, thus preventing unnecessary therapies, is the correlation with the clinical data aimed to exclude a primary neoplasm and an adequate follow-up. Nowadays, a fundamental diagnostic tool is represented by the FISH assessment of the CDKN2A gene status encoding p16 protein, which is known to play an important role in the development of several tumor types by regulating cell cycle. Since p16 is a tumor suppressor gene, the loss of both of the alleles is necessary for the development of a malignant process. Chung et al6 found that 33 out of 54 (61%) MM showed CDKN2A homozygous deletion, while none of reactive mesothelial cell proliferations showed deletion. Similarly, Wu et al7 showed that this gene alteration was seen in 86% of 50 MM cases but in none of 10 fibrous pleuritis cases, so confirming 100% specificity of the assay. Moreover, homozygous p16 deletion is reported to be a poor prognostic factor in pleural and peritoneal epithelioid mesothelioma.8,9 These data emphasize the opportunity to look for p16 deletion not only to differentiate between MM and nonneoplastic mesothelial proliferation but also to provide patients with a prognostic factor. In our case, FISH analysis, performed in both anatomical sites, displayed homozygous deletion in 100% mesothelial cells thereby enabling diagnosis of MM with nodal metastases and potential poor prognosis. A similar supraclavicular localization of a peritoneal malignant mesothelioma was first described by Sussman and Rosai10 in 1990, who presented a series of cases in which the mesothelioma diagnosis was made on metastatic nodes, also supporting the view that peritoneal MM were more prone to lymph node metastases than their
International Journal of Surgical Pathology 22(6) pleural counterpart. In one of these cases, a few months after an initial histologic diagnosis of hemangiopericytoma on a supraclavicular mass of a 56-year-old man, a laparotomy revealed a diffuse peritoneal seeding by MM. In the present case, FISH analysis in association with the worsening of the patient’s clinical situation were in keeping with the diagnosis of MM, while morphology and immunohistochemistry were not fully conclusive for malignancy. Therefore, such a test should be introduced in the diagnostic workup in the event of equivocal mesothelial cell proliferation. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Husain AN, Colby T, Ordonez N, et al. Guidelines for pathologic diagnosis of malignant mesothelioma. 2012 update of the consensus statement from the International Mesothelioma Interest Group. Arch Pathol Lab Med. 2013;137:647-667. 2. Brooks JS, LiVolsi VA, Pietra GG. Mesothelial cell inclusions in mediastinal lymph nodes mimicking metastatic carcinoma. Am J Clin Pathol. 1990;93:741-748. 3. Argani P, Rosai J. Hyperplastic mesothelial cells in lymph nodes: report of six cases of a benign process that can simulate metastatic involvement by mesothelioma or carcinoma. Hum Pathol. 1998;29:339-346. 4. Isotalo PA, Veinot JP, Jabi M. Hyperplastic mesothelial cells in mediastinal lymph node sinuses with extranodal lymphatic involvement. Arch Pathol Lab Med. 2000;124:609-613. 5. Suárez Vilela D, Izquierdo García FM. Hyperplastic mesothelial cells in mediastinal lymph node sinuses. Arch Pathol Lab Med. 2000;124:1749. 6. Chung CT, Santos Gda C, Hwang DM, et al. FISH assay development for the detection of p16/CDKN2A deletion in malignant pleural mesothelioma. J Clin Pathol. 2010;63:630-634. 7. Wu D, Hiroshima K, Matsumoto S, et al. Diagnostic usefulness of p16/CDKN2A FISH in distinguishing between sarcomatoid mesothelioma and fibrous pleuritis. Am J Clin Pathol. 2013;139:39-46. 8. Dacic S, Kothmaier H, Land S, et al. Prognostic significance of p16/cdkn2a loss in pleural malignant mesotheliomas. Virchows Arch. 2008;453:627-635. 9. Borczuk AC, Taub RN, Hesdorffer M, et al. P16 loss and mitotic activity predict poor survival in patients with peritoneal malignant mesothelioma. Clin Cancer Res. 2005;11:3303-3308. 10. Sussman J, Rosai J. Lymph node metastasis as the initial manifestation of malignant mesothelioma. Report of six cases. Am J Surg Pathol. 1990;14:819-828.
