Adenocarcinoma of the rete testis arising in the mediastinum testis is a rare, highly malignant neoplasm. Wedescribe one such case in a 25-year-old male who presented with a palpable right scrotal mass which metasta-sizedto the right inguinal lymph node eight months later. Ultrasonography of this tumor showed a complex cystic andsolid mass in the swollen right scrotum, which was separate from the right testis. Ultrasonographic and clinicalfindings suggested that the mass was, indeed, paratesticular. Surgical pathology following right radicalorchiectomy and hemiscrotectomy, however, confirmed the presence of an exophytic adenocarcinoma of the retetestis. A pelvic CT performed to evaluate a right inguinal mass, which was palpated eight months later, revealed amainly cystic mass in the right inguinal area. Metastasis was confirmed by biopsy.