A Case of Solitary Well‐Differentiated Papillary Mesothelioma with Invasive Foci in the Pleura

• Published in: Pathology international 2017-01, Vol.67 (1), p.45-49
• Main Authors: Shimizu, Shigeki, Yoon, Hyung‐Eun, Ito, Norimasa, Tsuji, Taisuke, Funakoshi, Yasunobu, Utsumi, Tomoki, Sakaguchi, Masahiro, Tsujimura, Toru, Kasai, Takahiko, Hiroshima, Kenzo, Matsumura, Akihide
• Format: Article
• Language: English
• Subjects: Adenocarcinoma; Adenocarcinoma - pathology; Adenocarcinoma of Lung; Biomarkers, Tumor - analysis; Case reports; Female; Fluorescence; Fluorescence in situ hybridization; Humans; Immunohistochemistry; In Situ Hybridization, Fluorescence; Invasiveness; Lung Neoplasms - pathology; Lungs; Mesothelioma; Mesothelioma - pathology; Middle Aged; Neoplasms, Multiple Primary - pathology; Nucleoli; Pleura; Pleural Neoplasms - pathology; solitary lesion; stromal invasion; well‐differentiated papillary mesothelioma
• ISSN: 1320-5463; 1440-1827
• DOI: 10.1111/pin.12483

Well‐differentiated papillary mesothelioma (WDPM) is a rare, distinct tumor consisting of mesothelial cells with a papillary architecture, bland cytological features, and a tendency toward superficial spread without invasion. Rare cases with superficial invasion are termed WDPM with invasive foci. We report a case of solitary WDPM with invasive foci in the pleura. A 61‐year‐old woman presented with a lung adenocarcinoma. A small papillary lesion measuring 29 × 10 × 8 mm was incidentally found in the parietal pleura during a lobectomy for the lung adenocarcinoma. The fibrovascular core of the small papillary lesion was surrounded by a single layer of cuboidal cells with mild to moderate atypia and large nucleoli. Atypical mesothelial cells focally invaded the submesothelial layer. The cells of the papillary lesion were positive for cytokeratins and mesothelial markers. The Ki67 index was