Peritoneal malignant mesothelioma metastatic to supraclavicular lymph nodes

Our plain-English summary of Peritoneal malignant mesothelioma metastatic to supraclavicular lymph nodes, by S. Zannella, M.A. Testi, G. Cattoretti, et al (International Journal of Surgical Pathology, 2014).

The study

• Authors: S. Zannella, M.A. Testi, G. Cattoretti, G. Pelosi, N. Zucchini
• Journal: International Journal of Surgical Pathology
• Published: 2014;22(6):552-4
• Type of article: Case report
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

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.

© The Author(s) 2014.

In plain English

This case report described a 62-year-old man admitted to hospital with acute abdominal pain. A CT scan showed an ill-defined mass in the peritoneum (the lining of the abdomen), and his appendix was removed. Under the microscope, mesothelial cells covered the appendix surface but showed only mild atypia and no clear invasion, so the criteria for malignant mesothelioma were not fully met. A few months later, scans showed enlarged lymph nodes in the chest, armpit and above the collarbone. A biopsy of a left supraclavicular node found the same cells filling the node's lymphatic channels, now looking more abnormal. A genetic test (fluorescence in situ hybridization, or FISH) found that both copies of the CDKN2A (p16) gene were missing in 100% of examined cells in both the appendix and lymph node samples. The authors concluded this enabled a diagnosis of malignant mesothelioma with lymph node metastases, and recommended the test for unclear cases. The patient had chemotherapy and was alive with disease at 10 months. The article did not mention asbestos.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Case report (single patient)
• Who was studied: One 62-year-old man admitted to hospital with acute abdominal pain, with a peritoneal mass on CT scan. The article does not say when the case occurred. The authors are based in hospitals and universities in Italy, but the article does not say where the patient was treated.
• Exposure: Not reported. The article does not mention asbestos or any other exposure for this patient.
• Main results:
  • In the appendix, there was a bland-looking proliferation of mesothelial-type cells, with a Ki-67 labeling index (a measure of cell growth) of 20%, but no clear evidence of invasion.
  • The supraclavicular lymph nodes contained the same type of cells as the appendix. In the lymph node these cells were more abnormal and had a higher Ki-67 labeling index of 30% to 40%.
  • FISH testing showed homozygous deletion of the CDKN2A gene (both copies missing) in 100% of examined cells, in both the appendix and the lymph node samples.
  • The patient received chemotherapy and was alive with disease at 10-month follow-up.
• The authors' conclusion: The authors concluded that the FISH finding in both sites enabled a diagnosis of malignant mesothelioma with lymph node metastases and potentially poor prognosis, when morphology and immunohistochemistry had not been conclusive. They stated that this test should be included in the diagnostic workup when a mesothelial cell proliferation is equivocal.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Peritoneal mesothelioma.

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Reactive Mesothelial Hyperplasia, Biopsy, Mesothelial Cells, CDKN2A, Fluorescence In Situ Hybridization (FISH), Homozygous Deletion, Reactive Mesothelial Cells.

Related studies

• Lymph node metastases in diffuse malignant peritoneal mesothelioma — D. Baratti, S. Kusamura, et al. (2010)
• Cytokeratin 19 expression in primary thoracic tumors and lymph node metastases — K. Masai, K. Nakagawa, et al. (2014)
• Fine-needle aspiration biopsy of axillary lymph nodes — S. Jaffer, M. Zakowski (2002)
• Lymph node involvement and metastatic lymph node ratio influence the survival of malignant pleural mesothelioma: a French multicenter retrospective study — I. Hysi, F. Le Pimpec-Barthes, et al. (2014)
• Extrathoracic lymph node metastases in malignant pleural mesothelioma — M. Huncharek, K. Smith (1988)
• Malignant pleural mesothelioma initially diagnosed on cervical lymph node biopsy — S. Ogata, S. Hiroi, et al. (2009)

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