[Klinefelter syndrome with hypogonadotropic hypogonadism and absence of Leydig cells].

Klinefelter's syndrome is characterized by hypergonadotropic hypogonadism, 47,XXY karyotype, gynecomastia, azoospermia and testicular atrophy with hyalinization of seminiferous tubules and hyperplasia of Leydig cells. Some cases of Klinefelter's syndrome with unexplainably low levels of gonadotropins have been reported in the literature. Two additional cases of Klinefelter's syndrome with hypogonadotropic hypogonadism and absence of Leydig cells are described.