Long Road to Identifying Peritoneal Mesothelioma: An Elusive Diagnosis

Our plain-English summary of Long Road to Identifying Peritoneal Mesothelioma: An Elusive Diagnosis, by T.S. Konduru, G. Gourisaria, G. Ozen, et al (Curēus, 2025).

The study

• Authors: T.S. Konduru, G. Gourisaria, G. Ozen, P. Karunakaran Thozhuthumparambil
• Journal: Curēus
• Published: 2025;17(6):e85973
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

Peritoneal mesothelioma is a rare and aggressive malignancy that often presents with non-specific abdominal symptoms such as ascites, leading to delayed diagnosis and treatment. It poses significant diagnostic challenges, especially in the absence of classical risk factors like asbestos exposure. We report the case of a 60-year-old woman with a background of coeliac disease and no known asbestos exposure, who presented with progressive abdominal distension and ascites. Initial investigations, including imaging, paracentesis, cytology and liver biopsy, failed to reveal a definitive cause. Despite multiple evaluations and treating a presumptive diagnosis of sarcoidosis, her symptoms persisted. One year after the initial presentation, imaging revealed peritoneal nodularity and enhancement. Following biopsy and immunohistochemistry, a multidisciplinary team discussion led to the diagnosis of peritoneal mesothelioma. The patient was commenced on chemotherapy which showed clinical improvement. This case underscores the importance of maintaining a high index of suspicion for rare malignancies such as peritoneal mesothelioma in patients with recurrent unexplained ascites, even in the absence of classical risk factors. Early multidisciplinary involvement and persistence in diagnostic evaluation are essential for timely diagnosis and management, which may improve patient outcomes in complex presentations.

Copyright © 2025, Konduru et al.

In plain English

This case report described one 60-year-old woman with coeliac disease. She was a retired carer from a nursing home with no prior history of asbestos exposure, according to the authors, who work at a hospital trust in Birmingham, UK. She came to the emergency department with five months of worsening abdominal swelling caused by fluid (ascites). Scans, fluid tests, tumour markers and a liver biopsy did not find a cause, and the fluid showed no malignant cells. A chest lymph node biopsy led to a presumed diagnosis of sarcoidosis, but four months of steroid treatment did not help. A later routine CT scan showed small nodules on the abdominal lining. A first biopsy of these nodules was inconclusive. After a specialist pathologist reviewed it, the findings, including loss of the BAP-1 protein, supported a final diagnosis of diffuse peritoneal mesothelioma of epithelioid type. That diagnosis came over a year after she first presented. She was not considered a candidate for surgery and started pemetrexed and cisplatin chemotherapy. Afterwards she needed one further fluid drainage, compared with seven before. The authors concluded that doctors should keep peritoneal mesothelioma in mind in recurrent unexplained ascites.

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 60-year-old woman with coeliac disease, hypertension, gastro-oesophageal reflux disease and osteoporosis. The authors are from Acute Internal Medicine, Sandwell and West Birmingham Hospitals NHS Trust, Birmingham, UK. The article gives no dates for the case.
• Exposure: No known asbestos exposure. She was a retired carer from a nursing home, a non-smoker, and did not drink alcohol.
• Main results:
  • Early ascitic fluid cytology in this patient found no malignant cells, and her tumour markers were negative.
  • A mediastinal lymph node biopsy showed non-necrotising granulomas. This led to a presumptive diagnosis of indolent sarcoidosis, which was later considered unlikely when four months of steroids gave no response.
  • A later CT scan showed mild peritoneal wall enhancement and a few small peritoneal nodules. The first biopsy of these nodules could not distinguish adenocarcinoma from mesothelial proliferation.
  • The ascitic fluid changed from transudative at first presentation to exudative, with a serum-ascites albumin gradient of 4.
  • Specialist pathology review found loss of nuclear BAP-1 expression with retained MTAP expression. Together with diffuse omental nodularity on imaging, this supported a final diagnosis of diffuse peritoneal mesothelioma of epithelioid type.
  • She was judged not a candidate for surgery and started pemetrexed and cisplatin. After that she needed one more paracentesis, compared with seven cycles before.
• The authors' conclusion: The authors concluded that the diagnosis was delayed by over a year, reflecting the rarity of the condition and its nonspecific features. In their view, doctors should keep a high index of suspicion for peritoneal mesothelioma in recurrent, unexplained ascites, and a persistent multidisciplinary approach is essential.

Topics

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Ascites, Asbestos Exposure, paracentesis, Cytology, Biopsy, Immunohistochemistry, Multidisciplinary Team.

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