Carcinoma in situ of the ectopic testis.

A young man with a palpable ectopic testis underwent right testis biopsy and orchiopexy. Since histological findings of the biopsy specimen revealed an unsuspected intratubular carcinoma in situ and evidence of diminished spermatogenic potential, an inguinal orchiectomy was done. This appears to be the first reported case of a tumor of this type developing in an undescended testis.