Paratesticular multicystic mass of Wolffian, probably paradidymal, origin.

A unilateral multicystic mass in the connective tissue adjacent to the vas deferens in a 46-year-old man is reported. Anatomically, it was distinct from the epididymis and vas and contained no sperm. The epithelial lining was simple, ciliated, and cuboidal to columnar. The cysts were surrounded by connective tissue collars containing smooth muscle. The authors postulate that this lesion represents a cystic hyperplasia of vestigial Wolffian duct remnants, based on its unique histologic features and the exclusion of other plausible explanations. The supraepididymal, paravasal location suggests origin in the paradidymis.