Malignant peritoneal mesothelioma presenting as a splenic mass

Our plain-English summary of Malignant peritoneal mesothelioma presenting as a splenic mass, by M. Podberezin, M.J. Fitzpatrick, L.P. Hariri, et al (Pathology, Research and Practice, 2020).

The study

• Authors: M. Podberezin, M.J. Fitzpatrick, L.P. Hariri, L. Sholl
• Journal: Pathology, Research and Practice
• Published: 2020;216(12):153273
• Type of article: Case report, Letter
• Read it: PubMed · Publisher

In plain English

This article is a case report, published as a letter, about one patient with peritoneal mesothelioma (mesothelioma of the abdominal lining) that first appeared as an enlarged spleen. A 52-year-old woman, otherwise healthy, had worsening pain in her left flank and left shoulder. A CT scan showed a mass inside the spleen measuring 14.2 cm. A core needle biopsy showed a high-grade tumor. Its microscopic features and stains were consistent with biphasic malignant mesothelioma. Because mesothelioma was not suspected at first, the biopsy stains did not include certain carcinoma markers. Surgeons removed the spleen together with parts of the liver, stomach, diaphragm and omentum. The tumor measured 24 cm and had also reached the stomach wall, the diaphragm and the omentum. Genetic testing found no changes that could be targeted with drugs. Despite chemotherapy, the cancer spread to the liver and lung, and she died five months after surgery. The authors concluded that this was locally advanced peritoneal mesothelioma mainly involving the spleen, which mimicked localized splenic mesothelioma. The article did not report whether the patient had been exposed to 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 (letter to the editor) of a single patient
• Who was studied: One 52-year-old otherwise healthy woman with worsening left flank and left shoulder pain. The authors were at hospitals in Massachusetts, United States; the date of the case is not given.
• Exposure: Not reported: the article gives no asbestos or other exposure history for this patient.
• Main results:
  • CT of the abdomen showed an enlarged spleen with a mass inside the spleen measuring 14.2 cm in greatest dimension.
  • Core biopsy of the spleen showed a high-grade malignant tumor. Tumor cells stained positive for calretinin, WT-1 and GATA-3, with markedly diminished BAP-1 expression.
  • MTAP staining did not show loss of expression. The authors stated that this did not affect the diagnosis because the tumor was clearly malignant.
  • The biopsy findings were consistent with biphasic malignant mesothelioma with pleomorphic features.
  • The spleen was removed in one block with the left lateral segment of the liver, the omentum, the left hemidiaphragm and the greater curvature of the stomach.
  • On gross examination the tumor measured 24 cm. It involved the gastric wall and the left hemidiaphragm, with multiple tumor deposits in the omentum.
  • Next-generation sequencing found no targetable alterations. Variants in RNF43, TP53 and NF2 were detected.
  • Despite chemotherapy, the patient developed widespread metastases to the liver and lung and died five months after surgery.
  • Despite the enlarged spleen, the patient had a high platelet count (thrombocytosis) rather than a low one. Its cause was not clear; molecular studies ruled out a chronic myeloproliferative neoplasm.
• The authors' conclusion: The authors concluded that the case represented locally advanced peritoneal mesothelioma with predominant involvement of the spleen, thus mimicking localized splenic mesothelioma.
• Limitations the authors state:
  • Because the sample was a core biopsy and mesothelioma was not initially suspected, the stain panel did not include broad carcinoma markers such as Ber-Ep4 and/or MOC31.

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.

Related studies

• Peritoneal mesothelioma presenting as an adnexal mass — R.A. Komorowski, D.H. Bobert (1975)
• Benign multicystic peritoneal mesothelioma presenting as a ghost abdominal mass — H. Jerraya, W. Ghariani, et al. (2016)
• Splenic localization of the peritoneal mesothelioma: case report and literature revue — D. D'Abbicco, A. Conversano, et al. (2012)
• A case of peritoneal mesothelioma masquerading as a urachal mass — K. Huynh, J. Krantz, et al. (2014)
• Peritoneal mesothelioma presenting surgically — P.G. Smith, P.M. Higgins, et al. (1968)
• Peritoneal mesothelioma presenting as umbilical tumor — W.S. Kwee, R.W. Veldhuizen, et al. (1982)

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