A rare case of intratesticular adenomatoid tumor is described. Pathologically and clinically this tumor is associated with the seminiferous tubules and the rete testis. The patient underwent left inguinal exploration to confirm the testicular tumor. A radical orchiectomy was performed. We believe this is the first case of documented intratesticular adenomatoid tumor that did not arise from either tunica albuginea or epididymis. The cytologic origin of adenomatoid tumors and an unusual finding of decreased spermatogenesis with marked atrophy of the testes are also presented.