Primary Myoepithelioma of the Testis - A Case Report

Myoepitheliomas are well-established to occur in the salivary glands, but they have also been described in the breast, upper aerodigestive tract, skin, and soft tissues. We report here on a unique case of primary myoepithelioma that occurred in the right testis of a 28-year-old man. The tumor was entirely confined to the testis and it was clearly separated from the epididymis. Histopathology revealed mixed architectural patterns in which the reticular areas merged into the chondromyxoid stroma. The tumor cells, which were focally immunoreactive to pancytokeratin and S-100 protein, were round to ovoid and spindly arranged in cords, strands, and fascicles. They showed mild nuclear pleomorphism, sparse mitotic figures and a low Ki-67 proliferative index. There was no ductal differentiation in the tumor. To the best of our knowledge, there has been only one case report of a primary testicular myoepithelioma in the English medical literature.