Adenocarcinoma of the rete testis.

Adenocarcinoma of the rete testis is a rare tumor. Histologic diagnosis is difficult, and in the past the tumor may have been incorrectly identified in a number of cases, leading to misleading information on the nature and behavior of this neoplasm. We present the case of a 39-year-old man with a long history of a small left hydrocele, who was lost to follow-up and presented again 2 years later with testicular discomfort. Sonographic findings were consistent with a testicular tumor. Histology confirmed low-grade adenocarcinoma of the rete testis, the first reported tumor of this grade. Previously reported cases of rete testis carcinoma are reviewed.