Pineal germinoma with syncytiotrophoblastic giant cells: a case with panhypopituitarism and isosexual pseudopuberty.

A previously healthy boy, aged 12 years, developed hypopituitarism due to suprasellar metastases from a pineal germinoma with syncytiotrophoblastic giant cells (SGC). Despite the hypopituitarism, the patient showed pubertal development, which was associated with abnormal levels of human chorionic gonadotropin (hCG) in the cerebrospinal fluid. This case adds support to the theory that precocious puberty in children with pineal germinomas may be due to the secretion of hCG by SGC, a minor component of the germinoma. It also illustrates the point that, although abnormal levels of circulating hCG in children with pineal tumors may indicate a diagnosis of choriocarcinoma with its encumbent poor prognosis, other pineal germ cell tumors may also secrete hCG. Although this patient had abnormal levels of hCG, his cerebral tumor exhibited behavior more commonly associated with pineal germinoma than with choriocarcinoma.