"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

Our plain-English summary of "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, by B. Rekhi, S. Pathuthara, D. Ajit, et al (Diagnostic Cytopathology, 2010).

The study

• Authors: B. Rekhi, S. Pathuthara, D. Ajit, S.V. Kane
• Journal: Diagnostic Cytopathology
• Published: 2010;38(6):435-9
• Type of article: Case report
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A diffuse peritoneal mesothelioma is a rare tumor. Exfoliative cytology forms the first step in the diagnosis of mesothelioma, since most of these cases presented with effusion. Despite well established cytomorphological features, a challenge exists in differentiating mesothelial cells, including reactive and malignant types from carcinoma cells and macrophages. Presence of "signet-ring" cells increases the diagnostic challenge as these can be forms of benign and malignant cells. Ancillary techniques like immunohistochemical (IHC) markers and ultrastructural analysis form useful adjunct in substantiating exact diagnosis. We report an unusual case study of a diffuse peritoneal mesothelioma in a 57-years-old lady, with no history of asbestos exposure, presenting with recurrent ascites, diagnosed on ascitic fluid cytology and on histology as an adenocarcinoma, based upon the presence of "signet-ring" cells. On review, clinicopathological correlation with IHC was helpful in forming correct diagnosis.

(c) 2009 Wiley-Liss, Inc.

In plain English

This case report described a 57-year-old woman referred in 2006 to Tata Memorial Hospital, Mumbai, India, with loss of appetite, weight loss and abdominal fluid (ascites). The article stated she had no history of asbestos exposure. Fluid examined elsewhere had been diagnosed as adenocarcinoma, a type of cancer. The authors' review kept that diagnosis because of "signet-ring" cells, whose nucleus is pushed to one side. After chemotherapy, she had surgery, and tissue from the omentum (a fatty abdominal layer) was also labeled adenocarcinoma. When the fluid returned, the authors reviewed all samples. Tissue stains for calretinin and HBME-1 were positive, and diffuse peritoneal mesothelioma was diagnosed. Pathologists at Manchester Royal Infirmary confirmed this with further stains. She was given etoposide and was keeping well at the last follow-up in 2008. The authors concluded that in recurrent ascites with an unknown primary cancer, mesothelioma should be considered despite no asbestos history and the presence of scattered cells, including signet-ring cells, in fluid smears. They noted one stain was unavailable, calretinin staining was unclear at first, and earlier samples lacked cell blocks.

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 57-year-old woman referred to Tata Memorial Hospital, Mumbai, India, in 2006 with anorexia, weight loss and ascites
• Exposure: No asbestos exposure reported; the patient had no history of asbestos exposure
• Main results:
  • The first fluid samples were diagnosed as adenocarcinoma because signet-ring cells were present
  • On the omental biopsy taken during cytoreductive surgery, tumor cells were positive for CK 7 and EMA, focally positive for desmin, CEA and WT-1, and negative for CK20; adenocarcinoma, possibly metastatic, was diagnosed
  • On review, additional calretinin and HBME-1 positivity on tissue sections led to a diagnosis of diffuse mesothelioma
  • External review at Manchester Royal Infirmary found CK5 and CK6 positive and BerEP4 negative, and confirmed diffuse malignant mesothelioma
  • After chemotherapy (paclitaxel and carboplatin), cytoreductive surgery, and later etoposide, the patient was keeping well at the last follow-up in 2008
• The authors' conclusion: The authors concluded that in a clinicoradiological context of recurrent ascites with unknown primary, mesothelioma should be considered despite a negative history of asbestos exposure and the presence of singly dissociated cells, including signet-ring cells, on fluid smears, with peritoneal carcinoma as the closest alternative, and that the diagnosis should be supported by ancillary studies including IHC
• Limitations the authors state:
  • BerEP4 staining was unavailable and calretinin staining was equivocal at the time of the initial biopsy
  • Cell blocks from the earlier fluid samples were not available for IHC

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: Peritoneal Mesothelioma, Ascites, Cytology, Mesothelioma, Mesothelial Cells, Carcinoma, Macrophage, Asbestos Exposure.

Related studies

• Mesothelioma with signet-ring cell features: report of 23 cases — N.G. Ordóñez (2013)
• Metastatic peritoneal mesothelioma in the setting of recurrent ascites: a case report — V. Samedi, S. White, et al. (2010)
• An unusual case of ascites: pitfalls in diagnosis of malignant peritoneal mesothelioma — J.R. Clark, W.B. Ross (2000)
• Signet ring cell mesothelioma; A diagnostic challenge — H. Wang, C. Herath (2019)
• Improving the cytological diagnosis of high-grade serous carcinoma in ascites with a panel of complementary biomarkers in cell blocks — X. Zhang, L. Chen, et al. (2018)
• The role of peritoneal biopsy in the diagnosis of ascites — P.F. Jenkins, M.J. Ward (1980)

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