Absence of intratubular germ cell neoplasia in testicular yolk sac tumors in children. A histochemical and immunohistochemical study.

The majority of testicular germ cell tumors in adults are accompanied by neoplastic intratubular germ cells; these cells were uniformly absent in ten pure yolk sac tumors (endodermal sinus tumors) of the testicle in children studied morphologically and immunohistochemically. These differences may reflect divergent pathogenetic mechanisms that in turn may explain the tendency for different histologic types of testicular germ cell tumors to occur at different ages and the discordant biologic behavior between germ cell tumors of similar morphologic type in children and adults.