Neoplasms that arise from trophoblastic cells, notably choriocarcinomas of the placenta and testes, secrete excessive amounts of chorionic gonadotrophin (CG); this entity falls into the category of eutopic hormone production. Alternatively, ectopic CG production is associated with hepatocellular carcinomas, gastrointestinal cancers, brain germinomas, or pineal tumours and lung cancers. Clinical syndromes caused by ectopic CG production include precocious puberty in children, gynaecomastia in adult males, and menstrual irregularities in women. From the standpoint of clinical oncology, the second clinical syndrome is important, since a greater number of adult patients than children have ectopic CG syndrome.
