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

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.

Keywords: Case report; Pleura; Stromal invasion; Well-differentiated papillary mesothelial tumor.

Fig. 1

(A) A large left-sided effusion with dystrophic calcifications and enhancing nodularity extending between the ribs with a para-aortic lower mediastinal focus. (B) Intraoperative view of diffuse widespread pleural plaques. (C) Well-differentiated papillary mesothelial tumor (WDPMT) with minimal invasion. Pleural biopsy showing superficial arborescent papillary formations, papillae lined by a single layer of bland mesothelial cells, and dense cellular stroma (superficially only) (H&E, ×25). (D) WDPMT with minimal invasion. BAP1 immunostaining shows nuclear retention (BAP1 IHC, ×100).