Well-Differentiated Papillary Mesothelial Tumor: An Unusual Radiologic Presentation: A Case Report

Our plain-English summary of Well-Differentiated Papillary Mesothelial Tumor: An Unusual Radiologic Presentation: A Case Report, by M. Abdelghafar, K. Anand, A. Paiva-Correia, et al (Journal of Chest Surgery, 2023).

The study

• Authors: M. Abdelghafar, K. Anand, A. Paiva-Correia, E.P. Smith, F.G. Salle, V. Joshi
• Journal: Journal of Chest Surgery
• Published: 2023;56(3):220-223
• Type of article: Case report
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Well-differentiated papillary mesothelial tumor (WDPMT) is an uncommon tumor, formerly named well-differentiated papillary mesothelioma in the 2015 World Health Organization classification. It has a characteristic papillary architecture, bland cytologic features, a tendency toward superficial spread without invasion, and a good prognosis due to its clinically indolent behavior with prolonged survival. Rare cases with superficial invasion are termed WDPMT with invasive foci. WDPMT occurs primarily in the peritoneum of reproductive-age women, but also rarely in the pleura. We report a case of a 60-year-old woman who developed WDPMT with minimal invasion in the pleura with atypical radiological features and a family history of mesothelioma and indirect asbestos exposure.

In plain English

This article is a case report about one 60-year-old woman with a well-differentiated papillary mesothelial tumor (WDPMT) of the pleura, the lining around the lung. She was short of breath because fluid kept building up around her left lung. She was a lifelong non-smoker. Her father had died of mesothelioma and reportedly had been exposed to asbestos at work. The authors described her as having indirect asbestos exposure and did not name a fiber type. A CT scan showed the fluid, irregular calcium deposits on the pleura and diaphragm, and nodular pleural thickening, which raised concern for mesothelioma. During keyhole surgery to take a biopsy, the surgeons saw widespread pleural plaques. Tissue tests, including a genetic test that showed no evidence of homozygous deletion of the CDKN2A gene, led to a diagnosis of WDPMT with minimal invasion and no evidence of malignant mesothelioma. She was placed under surveillance and showed no progression after 12 months. The authors concluded that, to their knowledge, this was the first such case with this combined imaging appearance.

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 (a single patient)
• Who was studied: One 60-year-old woman, a lifelong non-smoker, with a reaccumulating left-sided pleural effusion and a family history of mesothelioma (her father died of it). The authors are based at Wythenshawe Hospital, Manchester, UK. No dates are given.
• Exposure: Indirect asbestos exposure. Her father reportedly had occupational exposure to asbestos. No fiber type, product, route or dose is given.
• Main results:
  • CT of the patient's chest showed a large left-sided pleural effusion, irregular pleural and diaphragmatic dystrophic calcifications, and enhancing nodular pleural thickening.
  • The CT features were judged concerning for mesothelioma.
  • Diffuse widespread pleural plaques were seen during the biopsy operation.
  • In the patient's tumor tissue, BAP-1 staining was retained. GATA-3 was positive in about 5%–10% of stromal cells, and the Ki-67 labelling index was about 5%.
  • Two FISH studies of the tumor tissue showed no evidence of homozygous CDKN2A deletion, in 60 cells in the first study and 105 cells in the repeat study.
  • The diagnosis was WDPMT with minimal invasion, with no evidence of malignant mesothelioma.
  • The patient was placed under surveillance because the entity was considered benign. She showed no new clinical or radiological progression after 12 months of follow-up.
• The authors' conclusion: The authors concluded that this was a case of pleural WDPMT with invasive foci, seen on imaging as combined dystrophic pleural calcifications and irregular pleural thickening. To their knowledge it was the first case with this presentation.
• Limitations the authors state:
  • The authors stated that retained BAP1 staining alone cannot completely exclude in situ or invasive mesothelioma.
  • The authors stated that the absence of homozygous CDKN2A deletion does not exclude a diagnosis of mesothelioma.

Topics

Medical terms in this study, explained in our Lexicon: Well-Differentiated, Well-Differentiated Papillary Mesothelioma, Prognosis, Peritoneum, Pleura, Mesothelioma, Asbestos Exposure.

Related studies

• Spontaneous urinary bladder perforation: An unusual presentation of well-differentiated papillary peritoneum mesothelioma — A. Serao, F. Ambrosini, et al. (2022)
• BAP1 loss is unusual in well-differentiated papillary mesothelioma and may predict development of malignant mesothelioma — H.E. Lee, J.R. Molina, et al. (2018)
• L1CAM expression in cystic mesothelial lesions: a comparison with adenomatoid tumours, well-differentiated papillary mesothelial tumours and malignant mesotheliomas — G. Karpathiou, F. Casteillo, et al. (2021)
• Combined adenomatoid tumor and well differentiated papillary mesothelioma of the omentum — Y. Hatano, Y. Hirose, et al. (2011)
• Well-differentiated papillary mesothelioma — K.J. Butnor, T.A. Sporn, et al. (2001)
• Well-differentiated papillary mesothelioma of the peritoneum is genetically defined by mutually exclusive mutations in TRAF7 and CDC42 — M. Stevers, J.T. Rabban, et al. (2019)

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