Epididymal lymphoma: report of two cases and imaging findings.

Epididymal lymphoma is a very rare tumor that is difficult to differentiate radiologically from other paratesticular tumors. Most cases of epididymal lymphoma are secondary involvement of the epididymis in patients with testicular lymphoma. However, isolated epididymal lymphoma is very rare. We herein report two cases of isolated epididymal lymphoma with different imaging findings. Patient 1 was a 52-year-old man who presented with a painless scrotal mass. Patient 2 was a 65-year-old man who presented with painless scrotal swelling. Ultrasound (US) demonstrated different imaging findings: US in patient 1 showed a well-defined round mass in the tail of the epididymis with hypervascularity confined to the epididymis, while US in patient 2 showed diffuse infiltrative enlargement with hypervascularity confined to the epididymis. Orchiectomy performed in both patients revealed diffuse large B-cell lymphoma confined to the epididymis.