Paratesticular Well Differentiated Papillary Mesothelial Tumor

**Semantic type:** Neoplastic Process

**Definition:** A rare, indolent, usually solitary mesothelial neoplasm that arises from the tunica vaginalis. It is characterized by the presence of a papillary architecture in which the papillae are lined by cuboidal mesothelial cells. Mitotic figures are usually absent. Stromal invasion is absent or minimal. It usually manifests with a hydrocele and less frequently scrotal mass.

**Synonyms:** - Paratesticular Well-Differentiated Papillary Mesothelial Tumor - Testicular Adnexa Well Differentiated Papillary Mesothelial Tumor - Testicular Adnexa Well-Differentiated Papillary Mesothelial Tumor