Metastatic malignant mesothelioma presenting as colonic polyps

Our plain-English summary of Metastatic malignant mesothelioma presenting as colonic polyps, by A.V. Masangkay, M. Susin, R. Baker, et al (Human Pathology, 1997).

The study

• Authors: A.V. Masangkay, M. Susin, R. Baker, R. Ward, E. Kahn
• Journal: Human Pathology
• Published: 1997;28(8):993-5
• Type of article: Case report
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A 66-year-old male engineer diagnosed with malignant pleural mesothelioma 4 years previously had thoracotomy, radiotherapy, and chemotherapy. He was followed regularly with chest computed tomography (CT) scan and had been asymptomatic. During one of his physical examinations, routine sigmoidoscopy showed incidental colonic polyps which were biopsied. Subsequently, recurrence of pleural mesothelioma and peritoneal involvement by mesothelioma was documented. Two of the polyps showed metastatic malignant mesothelioma in the lamina propia which strongly resembled adenocarcinoma histologically causing difficulty in making definitive diagnosis. Review of the literature disclosed no previously documented similar occurrence. This case shows the importance of clinical history and ancillary laboratory procedures such as immunohistochemistry and electron microscopy to avoid diagnostic pitfalls.

In plain English

This article is a case report about one patient, a 66-year-old engineer with a long history of asbestos exposure at work. Four years earlier he had been diagnosed with malignant mesothelioma of the left pleura and treated with thoracotomy, 30 courses of radiation therapy and eight courses of chemotherapy. He had no symptoms when a routine sigmoidoscopy found three polyps in the right colon. One polyp was a tubular adenoma. The other two contained tumor and were first interpreted as metastatic adenocarcinoma of unknown primary, because his mesothelioma history was not yet known to the doctors examining them. Ten weeks after the biopsies he developed fluid in the abdomen (ascites), weight loss and cough, and a peritoneal biopsy showed malignant mesothelioma. Electron microscopy of the polyps showed findings similar to the peritoneal tumor, and the polyps were reclassified as metastatic malignant mesothelioma. The authors found no similar previously reported case. They concluded that malignant mesothelioma should be considered in diagnosing metastatic tumors of the colon, and that a careful clinical history is needed.

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 66-year-old male engineer, diagnosed 4 years earlier at another institution with left pleural malignant mesothelioma; seen at North Shore University Hospital, Manhasset, NY
• Exposure: Long history of occupational asbestos exposure; fiber type not stated
• Main results:
  • While the patient had no symptoms, routine sigmoidoscopy found three polyps in the right colon, which were biopsied
  • One of the three polyps (proximal ascending colon) was a tubular adenoma
  • The tumor-containing polyps were initially interpreted as metastatic adenocarcinoma of unknown primary
  • Ten weeks after the colonic biopsies, the patient developed ascites, weight loss and productive cough
  • Electron microscopy of the peritoneal biopsy confirmed mesothelioma
  • Electron microscopy of the colonic polyps showed findings similar to the peritoneum, and the polyps were reclassified as metastatic malignant mesothelioma
  • Staining results that the authors described as excluding adenocarcinoma: strong cytokeratin reactivity and negative CEA and Leu-M1
  • The authors knew of no previously reported case of malignant mesothelioma presenting as colonic polyps
• The authors' conclusion: The authors concluded that malignant mesothelioma should be considered in the differential diagnosis of metastatic tumors of the colon, and that a careful clinical history should be obtained so the necessary confirmatory studies can be done
• Limitations the authors state:
  • B72.3 and Ber-EP4 stains, which the authors say are more frequently expressed in adenocarcinoma than in mesothelioma, were not performed

Topics

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

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Pleural Mesothelioma, Thoracotomy, Chemotherapy, Mesothelioma, Adenocarcinoma, Immunohistochemistry.

Related studies

• Metastasis of pleural mesothelioma presenting as bleeding colonic polyp — S. Sibio, P. Sammartino, et al. (2011)
• Malignant pleural mesothelioma presenting as an acute surgical abdomen due to metastatic jejunal perforation — K. Gocho, K. Isobe, et al. (2010)
• Malignant peritoneal mesothelioma giving rise to multiple intestinal polyps — F.G. Mayall, A.R. Gibbs (1991)
• Benign multicystic mesothelioma with concurrent colonic adenocarcinoma: a report of two cases — A. Husain, M. Ozdemirli (2012)
• Carbonic anhydrase IX is expressed in mesothelioma and metastatic clear cell renal cell carcinoma of the lung — M.L. Ramsey, B.J. Yuh, et al. (2012)
• Metastatic pleural mesothelioma presenting with solitary involvement of the tongue: report of a new case and review of the literature — F. Zanconati, A. DelConte, et al. (2003)

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