Although pure testicular teratomas in prepubertal boys have not been reported to metastasize, testicular teratomas in adults are associated with clinical metastases in 60% of cases. Teratoma has a diverse biological potential, with propensity for local growth, distant metastases, and transformation to somatic malignant cell types. Teratoma is frequently found associated with other nonseminomatous histologies and is present in the retroperitoneum in 40% of postchemotherapy retroperitoneal lymph node dissections. Because of the chemoresitant nature of teratomas, complete surgical resection is the treatment of choice. Since the biology of teratoma is unpredictable and it is frequently found in the retroperitoneum following chemotherapy for nonseminomatous germ-cell tumors, complete control of the retroperitoneum is advocated for all patients regardless of residual mass size.
