Well-Differentiated Papillary Mesothelioma of the Tunica Vaginalis: Case Report and Systematic Review of Literature

A new classification system proposed by Brimo et al has allowed stratification of mesothelioma into 3 categories: (1) well-differentiated papillary mesothelioma (WPDM); (2) mesothelioma of uncertain malignant potential; and (3) malignant mesothelioma. We report a case of WDPM of the tunica vaginalis, and performed a comprehensive search to include all available cases of WDPM reported in the literature, detailing age of onset, presentation, size, treatment, focality, laterality, testicular involvement, asbestos exposure, and disease-free follow-up. Histological features that constitute WPDM include (1) tubular-papillary architecture, (2) bland nuclear cytology, (3) low mitotic activity, (4) lined by a single row of cuboidal cells, and (5) lacking stromal invasion. Asbestos exposure, traditionally thought to be strongly correlated with well-differentiated mesothelioma, appears to have no correlation with the development of WDPM. As none of the cases of WDPM reported in the literature has shown any relapse, we propose that wide local excision rather than orchiectomy can be performed, especially among young adults with WDPM. We believe that this comprehensive report will help shape clinical practice about the diagnosis and therapeutic implications for WDPM.