Primary malignant peritoneal mesothelioma mimicking tuberculous peritonitis: A case report

Our plain-English summary of Primary malignant peritoneal mesothelioma mimicking tuberculous peritonitis: A case report, by L.C. Lin, W.Y. Kuan, B.H. Shiu, et al (World Journal of Clinical Cases, 2022).

The study

• Authors: L.C. Lin, W.Y. Kuan, B.H. Shiu, Y.T. Wang, W.R. Chao, C.C. Wang
• Journal: World Journal of Clinical Cases
• Published: 2022;10(10):3156-3163
• Type of article: Case report
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Malignant peritoneal mesothelioma (MPM) is a rare malignancy arising in mesothelial cells in the peritoneum. It can be mistaken for many other diseases, such as peritoneal carcinomatosis and tuberculous peritonitis (TBP), because its clinical manifestations are often nonspecific. Therefore, the diagnosis of MPM is often challenging and delayed.

Case Summary: A 42-year-old man was referred to our hospital with lower abdominal pain for 1 wk and ascites observed under abdominal sonography. His laboratory findings revealed an isolated elevated tumor marker of carcinoma antigen 125 (167.4 U/mL; normal, < 35 U/mL), and contrast enhanced computed tomography showed peritoneal thickening. Thus, differential diagnoses of TBP, carcinomatosis of an unknown nature, and primary peritoneal malignancy were considered. After both esophagogastroduodenoscopy and colonoscopy produced negative findings, laparoscopic intervention was performed. The histopathological results revealed mesothelioma invasion into soft tissue composed of a papillary, tubular, single-cell arrangement of epithelioid cells. In addition, immunohistochemical staining was positive for mesothelioma markers and negative for adenocarcinoma markers. Based on the above findings, TBP was excluded, and the patient was diagnosed with MPM.

Conclusion: It is important to distinguish MPM from TBP because they have similar symptoms and blood test findings.

©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.

In plain English

This case report describes one patient diagnosed at a hospital in Taichung, Taiwan. A 42-year-old Canadian man living in Taiwan for 5 to 6 years was admitted with one week of lower abdominal pain and fluid in the abdomen (ascites). His tumor marker CA-125 was raised at 167.4 U/mL (reference range 0-35), while his other tumor markers were normal. CT scans showed irregular thickening of the abdominal lining. After stomach and bowel scopes found no malignant lesion, laparoscopy revealed many whitish nodules. A biopsy of the abdominal lining showed epithelioid cells that were positive for mesothelioma markers and negative for adenocarcinoma markers. Staining of the abdominal fluid showed no definite microorganism. He was diagnosed with malignant peritoneal mesothelioma, epithelioid subtype. He recalled many houses with asbestos roofs in his childhood in Canada, but the authors could not weigh this risk factor. Follow-up of his treatment and outcome was lost after he decided to return to Canada for treatment. The authors concluded that diagnostic laparoscopy provided a precise method for confirming the diagnosis.

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 42-year-old Canadian man living in Taiwan, admitted to Chung Shan Medical University Hospital, Taichung, Taiwan, with lower abdominal pain
• Exposure: The article reports no measured or occupational asbestos exposure. The patient recalled many houses with asbestos roofs during his childhood in Canada. No fiber type is given, and the authors could not weigh this as a risk factor.
• Main results:
  • The patient's CA-125 was elevated at 167.4 U/mL (reference range 0-35). His other tumor markers (carcinoembryonic antigen, carcinoma antigen 199, tissue polypeptide antigen) were within normal limits.
  • Contrast-enhanced CT showed irregular peritoneal thickening over the perihepatic and pelvic peritoneum.
  • Esophagogastroduodenoscopy and colonoscopy found no malignant lesion.
  • At laparoscopy, multiple whitish nodules were seen throughout the abdominal cavity, and the peritoneal cancer index was over 10.
  • Immunohistochemical staining of the peritoneal biopsy was positive for calretinin and focally positive for WT-1. It was negative for the adenocarcinoma markers PAX-8, TTF-1 and CDX-2.
  • In the ascitic fluid analysis, no definite microorganism was seen on periodic acid-Schiff, Gomori methenamine silver or acid-fast staining.
  • The final diagnosis was malignant peritoneal mesothelioma, epithelioid subtype, and tuberculous peritonitis was excluded.
• The authors' conclusion: The authors concluded that diagnostic laparoscopy provided a precise method for confirming the diagnosis in this patient with unexplained ascites. They added that the case highlights the need for high clinical suspicion of MPM when a patient's features mimic tuberculous peritonitis.
• Limitations the authors state:
  • The authors could not quantify or weigh possible risk factors, including the patient's recollection of asbestos roofs on houses during his childhood in Canada.
  • Follow-up of treatment and outcome was lost because the patient decided to return to Canada for further treatment.

Topics

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Mesothelial Cells, Peritoneum, Ascites, Tumor Marker, Carcinoma, Mesothelioma, Epithelioid.

Related studies

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• Asymptomatic primary tuberculous pleurisy with intense 18-fluorodeoxyglucose uptake mimicking malignant mesothelioma — T. Shinohara, N. Shiota, et al. (2013)
• Utility of Ascitic Fluid Adenosine Deaminase Levels in the Diagnosis of Tuberculous Peritonitis in General Medical Practice — A. Kumabe, S. Hatakeyama, et al. (2020)
• Case Report: tuberculous pleurisy mimicking mesothelioma in a 37-year-old Chinese woman — X. Liu, T. Cao, et al. (2025)
• A diagnostic trap: Malignant pericardial effusion mimicking tuberculous pericarditis — M. Rashmika, U. Jadhav, et al. (2026)
• Metastatic primary peritoneal malignant mesothelioma mimicking primary diffuse gastric carcinoma: a rare encounter in gastric biopsy — Y. Yang, D. Gunawardane, et al. (2017)

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