Malignant epithelial mesothelioma of the peritoneum: observations on a problem case

Our plain-English summary of Malignant epithelial mesothelioma of the peritoneum: observations on a problem case, by B.P. Eyden, S. Banik, M. Harris (Ultrastructural Pathology, 1996).

The study

• Authors: B.P. Eyden, S. Banik, M. Harris
• Journal: Ultrastructural Pathology
• Published: 1996;20(4):337-44
• Type of article: Case report
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A 71-year-old asbestos-exposed male with symptoms suggestive of asbestosis for the previous 8 years presented with abdominal distension and ascites. Clinically, a diagnosis of mesothelioma carcinoma was made. Light microscopy of an omental biopsy failed to advance the diagnosis: The tumor was a solid, papillary, and glandular neoplasm lacking mucin and hyaluronidase-sensitive Alcian blue staining material. Immunohistochemistry gave positive results for Ber-EP4, LeuM1, and CEA, markers, favoring carcinoma. Electron microscopy revealed processes in channels and lumina, which were long, slender, and uncoated with a length: diameter ratio of 19.7. A few possessed small rootlets. A glycocalyx and glycocalyceal bodies were not seen. Other features included tonofibrils, a basal lamina, and desmosomes. The patient died 3 months following the onset of abdominal symptoms. Autopsy findings included solid and papillary tumor throughout the peritoneum, but no intrinsic tumor of the gastrointestinal tract or elsewhere. Arriving at a final diagnosis was complicated by immunohistochemistry, which favored carcinoma, and ultrastructure, which suggested mesothelioma. Taking into account all lines of evidence, it was concluded that the tumor was probably a mesothelioma but one with some features developed to an extent more typical of carcinoma.

In plain English

This case report described a man whose abdominal tumor was hard to classify as peritoneal mesothelioma or carcinoma. The 71-year-old had a history of asbestos exposure from 38 years of power station work and 8 years of symptoms suggestive of asbestosis. He came to medical attention with abdominal swelling and fluid in the abdomen (ascites). A CT scan showed calcified pleural plaques and thickening and fibrosis of the mesentery. A biopsy of the omentum showed a solid, papillary and glandular tumor. Three markers (Ber-EP4, LeuM1 and CEA) stained positive, which the authors felt pointed to carcinoma. Under the electron microscope, the tumor had long, slender microvilli with a length-to-diameter ratio of 19.7 and no glycocalyx, features suggesting mesothelioma. A minority of the microvilli had small rootlets, a feature typical of some carcinomas. He died 3 months after his abdominal symptoms began. At autopsy, tumor was found throughout the peritoneum with lymph node spread, but no intrinsic tumor of the gastrointestinal tract or elsewhere. The authors concluded the tumor was probably a mesothelioma with some features more typical of carcinoma. The article did not name a fiber type.

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), with light microscopy, immunohistochemistry, electron microscopy and autopsy findings
• Who was studied: one 71-year-old man with abdominal distension and ascites
• Exposure: asbestos exposure from 38 years of work in a power station; fiber type not stated
• Main results:
  • For the previous 8 years the patient had had symptoms suggestive of asbestosis.
  • A CT scan showed calcified pleural plaques and thickening and fibrosis of the mesentery.
  • The omental biopsy showed a solid, papillary, and glandular tumor.
  • The omental biopsy showed no convincing neutral mucin and no convincing hyaluronidase-sensitive Alcian blue staining material.
  • The tumor was positive for Ber-EP4, CEA and LeuM1, which the authors felt indicated carcinoma.
  • Electron microscopy showed microvilli with a length-to-diameter ratio (LDR) of 19.7.
  • A minority of microvilli had modestly developed rootlets. A glycocalyx and glycocalyceal bodies were not seen.
  • The patient died 3 months after the onset of abdominal symptoms.
  • At autopsy, tumor identical to the biopsy was found throughout the peritoneum with lymph node metastases, and there was no intrinsic tumor of the gastrointestinal tract or elsewhere. Bilateral pleural hyaline plaques and pericardial plaques were also present.
• The authors' conclusion: The authors concluded the tumor was best regarded as probably a mesothelioma, with some aspects of its immunophenotype more typical of carcinoma.
• Limitations the authors state:
  • Only the omental biopsy was available for light and electron microscopy.
  • The authors noted it is difficult to apply general microvillus ratio values, derived from groups of tumors, to a single tumor.

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: Mesothelioma, Peritoneum, Ascites, Carcinoma, Biopsy, Neoplasm, Immunohistochemistry, Ber-EP4.

Related studies

• 'Mucin-positive' epithelial mesothelioma of the peritoneum: an unusual diagnostic pitfall — D.S. Cook, R.L. Attanoos, et al. (2000)
• Value of mesothelial and epithelial antibodies in distinguishing diffuse peritoneal mesothelioma in females from serous papillary carcinoma of the ovary and peritoneum — R.L. Attanoos, R. Webb, et al. (2002)
• Mucin-positive epithelial mesothelioma of the peritoneum: small bowel involvement — J.H. Kim, K.Y. Kwon, et al. (2011)
• Malignant mesothelioma of the peritoneum: case reports and immunohistochemical findings including Ki-67 expression — H. Hirano, T. Fujisawa, et al. (2010)
• Primary epithelioid haemangioendothelioma of the peritoneum: an unusual mimic of diffuse malignant mesothelioma — R.L. Attanoos, N.S. Dallimore, et al. (1997)
• Desmoplastic malignant mesothelioma originating from the peritoneum — H. Takamaru, Y. Arimura, et al. (2012)

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