Germ cell expression of placental alkaline phosphatase in male pseudohermaphroditism

We have reviewed testes removed from 14 individuals with male pseudohermaphroditism (13 with androgen insensitivity and one with 17 alpha-hydroxylase deficiency) and have studied staining for placental alkaline phosphatase in germ cells. Placental alkaline phosphatase positivity was identified in fetal and premature neonatal controls but not in cryptorchid males or normal autopsy control material from boys older than 6 months. It was present in autopsy testes younger than 6 months and cases of androgen insensitivity in boys younger than 8 months, suggesting immaturity. It was also expressed in two patients with male pseudohermaphroditism aged 5 years and 14 years, both of whom had intra-tubular germ cell neoplasia by morphological criteria. Our study confirms the use of placental alkaline phosphatase as a marker of germ cell neoplasia in this specific group who are at high risk of malignancy.