Signet ring cell mesothelioma; A diagnostic challenge

Our plain-English summary of Signet ring cell mesothelioma; A diagnostic challenge, by H. Wang, C. Herath (Pathology, Research and Practice, 2019).

The study

• Authors: H. Wang, C. Herath
• Journal: Pathology, Research and Practice
• Published: 2019;215(7):152462
• Type of article: Review
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Signet ring cell mesothelioma is a rare variant of epithelioid mesothelioma with limited cases published. It has a male predilection and most commonly occurs on pleura; it can also arise in the peritoneal cavity. The signet ring cell morphology can pose a challenge leading to a potential diagnostic error. A variety of benign and malignant diseases, including reactive histiocytic hyperplasia, adenocarcinoma, melanoma, and lymphoma with signet ring cell morphology should be considered in the differential diagnosis. In signet ring cell mesothelioma work up, mucin stains are of limited value. Even though immunohistochemistry is routinely used in mesothelioma diagnosis, there is no sole specific mesothelial marker. Hence, a panel of mesothelial and epithelial markers are used; these should be interpreted with caution especially in this variant. Electron microscopy and genetic testing can be very helpful in distinguishing signet ring cell mesothelioma from its mimickers.

Copyright © 2019 Elsevier GmbH. All rights reserved.

In plain English

This article was a review by two pathologists in Saskatoon, Canada, of signet ring cell mesothelioma. This is a rare form of epithelioid mesothelioma whose cells can look like those of other diseases. The article reported no new patients or research data. The authors counted 27 cases in the English-language literature: 23 pleural and four peritoneal, 23 in men and four in women. Of these patients, 13 had a history of asbestos exposure and 17 were smokers. The authors wrote that there is no clear evidence that occupational asbestos exposure or smoking increases the risk of this tumor. Citing an earlier series, they reported a median survival of 15 months after diagnosis. They noted that three published cases were first misdiagnosed as metastatic adenocarcinoma. On laboratory tests, the authors wrote that mucin stains are of limited value and that no single mesothelioma marker should be used alone. They wrote that claudin-4 staining, electron microscopy, and tests for p16/CDKN2A deletion and loss of BAP1 staining can help. The authors concluded that pathologists should be aware of this tumor's diagnostic pitfalls.

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: narrative review (overview of published cases and diagnostic methods); no new cases reported
• Who was studied: 27 published cases of signet ring cell mesothelioma in the English literature: 23 pleural, 4 peritoneal
• Exposure: among the 27 published cases, 13 patients had a history of asbestos exposure (no fiber type given) and 17 were smokers
• Main results:
  • Of the 27 published cases, 23 patients were men and 4 were women
  • The authors stated there is no clear evidence that occupational asbestos exposure or smoking increases the risk of developing signet ring cell mesothelioma
  • Median survival after diagnosis was 15 months, as reported in a cited earlier series
  • Three published cases were initially misdiagnosed as metastatic adenocarcinoma
  • Mucin stains were described as of limited use in diagnosing mesothelioma
  • No single mesothelioma marker should be used alone
  • Claudin-4 was recommended because it stains most epithelial cells but not mesothelial cells
  • Electron microscopy was described as very helpful in diagnosis
  • FISH testing for p16/CDKN2A deletion and loss of BAP1 nuclear staining were described as supportive evidence for a mesothelioma diagnosis
• The authors' conclusion: The authors concluded that signet ring cell mesothelioma can mimic other diseases and that pathologists should be aware of its diagnostic pitfalls
• Limitations the authors state:
  • Because the tumor is rare, only a limited number of cases have been reported

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Epithelioid, Pleura, Peritoneal Cavity, Adenocarcinoma, Differential Diagnosis, Immunohistochemistry.

Related studies

• Mesothelioma with signet-ring cell features: report of 23 cases — N.G. Ordóñez (2013)
• "Signet-ring" cells--a caveat in the diagnosis of a diffuse peritoneal mesothelioma occurring in a lady presenting with recurrent ascites: an unusual case report — B. Rekhi, S. Pathuthara, et al. (2010)
• Signet-ring cell appearance of atrophic fat cells — J.D. Gilbert, N.E.I. Langlois, et al. (2021)
• Pulmonary acantholytic squamous cell carcinoma with focal signet ring cell morphology mimicking malignant mesothelioma on fine needle aspiration cytology: a case report — S.E. Choi, H.S. Park (2016)
• MicroRNA profiling in serous cavity specimens: Diagnostic challenges and new opportunities — L. Nicolè, F. Cappello, et al. (2019)
• The diagnostic challenge of peritoneal mesothelioma — P. Krasuski, A. Poniecka, et al. (2002)

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