Abstract
Feminization and precocious pubertal development are manifestations of hormone production by both benign and malignant testicular tumors. The pathophysiologic mechanisms underlying these clinical syndromes vary not only with the cell type of the tumor but also with the age of the host. Recent refinements in the ability to measure both steroidal and polypeptide hormones have provided both a new insight into these mechanisms and also useful parameters for monitoring therapy in these disorders.