Primary adenocarcinoma of the epididymis: case report.

Primary epididymal malignancies are uncommon and usually benign. Benign paratesticular tumors are most commonly adenomatoid, while the most common malignant paratesticular tumors are rhabdomyosarcomas. Approximately 25% of all epididymal tumors are malignant, and of the benign tumors, 60% to 78% are adenomatoid tumors.