Adenomatoid tumors (ATs) are relatively uncommon benign tumors usually arising in the paratesticular area. Among different theories proposed for its histogenesis, the most favored one seems to be the mesothelial origin, supported by different immunohistochemical and ultrastructural studies. As a consequence of the variety of morphologic patterns observed for ATs, the differential diagnosis of these tumors is quite extensive, ranging from benign to malignant tumors of both epithelial and stromal origin. These tumors represent a diagnostic challenge due to their clinical signs similar to those of other testicular neoplasms and ultrasonography nonspecific findings. The importance of a correct diagnosis implies avoidance of unnecessary orchiectomy, thereby maintaining endogenous testosterone production and fertility potential at its fullest. Clinical outcome is excellent in all cases, with no published relapses, and follow-up by postoperative ultrasound is sufficient.

We report a case of AT occurring in the tunica albuginea of the right testis in a 48-year-old man, referred to our Institute for a diagnostic revision. A brief review of the literature is also addressed, with a focus on histogenesis, clinico-pathologic characteristics and differential diagnoses of these rare neoplasms.