Testicular germ cell tumors

Testicular cancer corresponds to approximately 1-2 % of tumors in men; however, they are the most common malignancy in those between the ages of 15 and 34. About 95 % of testicular tumors are germ cell tumors (GCT). Significant improvements in our understanding of the underlying pathogenesis and molecular biology in recent years have resulted in a new classification of GCT. Testicular GCT fall mainly within three pathogenetic types and include prepubertal-type tumors (type I GCT), encompassing teratomas and yolk sac tumors; postpubertal tumors (type II GCT), encompassing seminomatous and non-seminomatous GCT - by far the most common ones; and spermatocytic tumor (type III GCT), a unique type of GCT occurring exclusively in the testis. Association with germ cell neoplasia in situ (GCNIS, formerly referred to as intratubular germ cell neoplasia or carcinoma in situ) plays a pivotal role in the most recent WHO classification of GCT in the testis. Subtypes associated with GCNIS include seminoma, embryonal carcinoma, choriocarcinoma and other trophoblastic tumors, postpubertal types of yolk sac tumor and teratoma, and mixed germ cell tumors, and correspond to pathogenetic type II GCT. Subtypes not associated with GCNIS include spermatocytic tumor and prepubertal types of yolk sac tumors and teratomas, including dermoid cysts. Other types of GCT include carcinoid tumors and the mixed GCT/sex cord-stromal tumor gonadoblastoma. Management of GCT frequently includes primary or post-chemotherapy retroperitoneal lymph node dissection. These specimens render a spectrum of pathologic findings that need to be appropriately recognized by the surgical pathologist as they may impact subsequent management and prognosis.