Rare Epididymal-Derived Myoepithelial Carcinoma: A Case Report and Review of Literature.

Myoepithelial carcinoma (MC), also known as malignant myoepithelial neoplasm, is more common in the parotid glands of the head and neck. The main clinical manifestation is the growth of a nonspecific, painless mass at the primary site. We report the first case of MC derived from the epididymis. The current reports of non-parotid MC are still rare, and epididymal-derived MC has not been reported previously. Simultaneously, we explore the role of EWSR1 fusion as a predicting marker and further reveal the origin of MC to provide new ideas for its diagnosis and treatment.