Retroperitoneal mature teratoma after orchidectomy for a stage IB pure embryonal testicular carcinoma.

Nonseminomatous germ cell tumor of the testis stage I will relapse in approximately 30% of patients in the first year after orchidectomy. We report a 19-year-old patient on active surveillance who presented with a retroperitoneal lymph node enlargement suggestive of metastatic disease more than 1 year after the initial diagnosis of embryonal carcinoma stage IB. Complete resection of the lymph node was performed and showed the presence of mature teratoma. Our patient had an unusual case of metastasis formation of benign histology of a previously removed highly malignant primary tumor confined to the testis.