From the archives of the AFIP: primary peritoneal tumors: imaging features with pathologic correlation

Our plain-English summary of From the archives of the AFIP: primary peritoneal tumors: imaging features with pathologic correlation, by A.D. Levy, J. Arnáiz, J.C. Shaw, et al (Radiographics, 2008).

The study

• Authors: A.D. Levy, J. Arnáiz, J.C. Shaw, L.H. Sobin
• Journal: Radiographics
• Published: 2008;28(2):583-607; quiz 621-2
• Type of article: Review
• Cited by: 140 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Primary peritoneal tumors are uncommon lesions that arise from the mesothelial or submesothelial layers of the peritoneum. Primary malignant mesothelioma, multicystic mesothelioma, primary peritoneal serous carcinoma, leiomyomatosis peritonealis disseminata, and desmoplastic small round cell tumor are the most prominent of these rare lesions. Primary malignant mesothelioma is a highly aggressive malignancy that occurs most commonly in older men and that has a strong association with high levels of asbestos exposure. It manifests most often as diffuse sheetlike or nodular thickening of the peritoneal surfaces, but it may occasionally be a localized mass. Multicystic mesothelioma occurs most frequently in women and has benign or indolent biologic behavior in the majority of patients. It is a multilocular cystic mass that arises from the pelvic peritoneal surfaces. Primary peritoneal serous carcinoma occurs almost exclusively in women. It is histologically identical to ovarian serous carcinoma and may be indistinguishable from metastatic ovarian carcinoma at imaging studies. Leiomyomatosis peritonealis disseminata is a rare, benign proliferative process that also occurs exclusively in women and is characterized by multiple smooth muscle nodules throughout the peritoneum. Desmoplastic small round cell tumor is a highly aggressive malignancy of unknown origin that occurs most often in the peritoneal cavity of young men. This unusual group of tumors is linked together by a common site of origin and imaging manifestations that mimic those of peritoneal carcinomatosis. Knowledge of the spectrum of imaging findings in this group of primary peritoneal tumors, along with their clinical and pathologic characteristics, is important in the evaluation of patients with diffuse peritoneal disease.

In plain English

This article was a review of tumors that start in the lining of the abdomen (the peritoneum). The authors summarized the published literature and their own experience with cases from the Radiologic Pathology Archives at the Armed Forces Institute of Pathology. They did not say how many cases they drew on. The review covered peritoneal malignant mesothelioma, multicystic mesothelioma, primary peritoneal serous carcinoma, desmoplastic small round cell tumor and other rare tumors. Citing an earlier study, the authors wrote that in men asbestos exposure had been shown to be the cause of 90% of pleural and 60% of peritoneal malignant mesotheliomas. They also wrote that only 23% of women with peritoneal malignant mesothelioma had been exposed to asbestos. They described two scan patterns of diffuse peritoneal malignant mesothelioma: sheetlike thickening of the lining, and focal masses. In their experience, both patterns occurred in all tissue subtypes. Calcified pleural plaques in the chest could be present alongside it. The authors concluded that on scans these tumors overlap with cancer that has spread through the abdomen, and that telling them apart matters for patient management.

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: Review (educational radiology-pathology review of the literature, illustrated with cases from the AFIP archives)
• Who was studied: Published literature on primary peritoneal tumors, plus illustrative patients from the Radiologic Pathology Archives at the Armed Forces Institute of Pathology (number of cases not stated). Examples include men with peritoneal mesothelioma who had histories of asbestos exposure, one former shipyard worker, and a 47-year-old man with no asbestos exposure.
• Exposure: Asbestos exposure was discussed as a cause of peritoneal malignant mesothelioma, drawing on cited literature. Fiber types were not specified. Erionite, therapeutic irradiation, simian virus 40 and chronic irritation were also mentioned as other implicated factors.
• Main results:
  • Citing an earlier study (reference 7), the authors stated that in men asbestos exposure had been shown to be the cause of 90% of pleural and 60% of peritoneal malignant mesotheliomas.
  • Citing an earlier source (reference 1), the authors stated that only 23% of women who develop peritoneal malignant mesothelioma had been exposed to asbestos.
  • Citing an earlier source (reference 6), peritoneal primary mesotheliomas account for 6% to 10% of malignant mesotheliomas.
  • Diffuse peritoneal malignant mesothelioma produces two patterns on cross-sectional images: diffuse involvement of the peritoneal cavity, and focal intraperitoneal masses.
  • In the authors' own experience, both imaging patterns occurred in all subtypes of peritoneal malignant mesothelioma. This agreed with an earlier series by Kebapci et al and not with that of Ros et al.
  • In an illustrative case of a man with asbestos exposure and peritoneal mesothelioma, CT showed calcified asbestos-related pleural plaques. The authors wrote that mesothelioma should be considered when sheetlike peritoneal thickening is accompanied by imaging evidence of asbestos exposure.
  • Well-differentiated papillary mesothelioma, a separate entity occurring mainly in women, has no reported association with asbestos exposure.
• The authors' conclusion: The authors concluded that primary peritoneal tumors share a site of origin and have overlapping imaging features that resemble diffuse peritoneal metastatic disease. They stated that distinguishing these tumors from metastatic disease is clinically important for appropriate patient management.
• Limitations the authors state:
  • The authors stated that their knowledge of the MR imaging features of malignant mesothelioma was based on a few case reports in the literature.

Topics

Medical terms in this study, explained in our Lexicon: Peritoneum, Malignant Mesothelioma, Multicystic Mesothelioma (MCM), Carcinoma, Desmoplastic Small Round Cell Tumor, Asbestos Exposure, Ovarian Serous Carcinoma, Peritoneal Cavity.

Related studies

• From the archives of the AFIP. Malignant pleural mesothelioma: radiologic-pathologic correlation — B.H. Miller, M.L. Rosado-de-Christenson, et al. (1996)
• Primary malignant tumors of peritoneal and retroperitoneal origin: clinical and imaging features — M.G. Lubner, J.L. Hinshaw, et al. (2014)
• The Pathologic Peritoneal Cancer Index (PCI) Strongly Differs From the Surgical PCI in Peritoneal Metastases Arising From Various Primary Tumors — A. Bhatt, Y. Yonemura, et al. (2020)
• Primary pericardial tumors — C.S. Restrepo, D. Vargas, et al. (2013)
• Benign Multicystic Peritoneal Mesothelioma: AIRP Best Cases in Radiologic-Pathologic Correlation — R. Lee, A. Tong, et al. (2016)
• Multimodality imaging of common and uncommon peritoneal diseases: a review for radiologists — R.A. Vicens, M. Patnana, et al. (2015)

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