Adenocarcinoma Originating from a Mature Teratoma of the Testis

Malignant transformation in testicular teratomas has been reported very rarely in the literature. Although testicular teratomas in childhood are regarded as benign neoplasms, these tumors, if left untreated until advanced ages, may present the risk of malignant transformation. We report a case of differentiated adenocarcinoma originating from colonic glands in primary testicular teratoma.