Localization of carcinoembryonic antigen in mature intracranial teratomas.

Carcinoembryonic antigen (CEA) in serum and cerebrospinal fluid (CSF) was measured in four patients with intracranial teratoma. The CEA levels were elevated in the CSF of two patients, but were within normal limits in the serum of all four. After surgical removal of the teratomas, which were verified as mature teratomas, CEA was localized by an immunohistochemical method. Positive reactions both to anti-CEA serum and to another anti-CEA serum absorbed with nonspecific cross-reacting antigen were seen in glandular structures, with or without goblet cells, and in some portions of stratified squamous epithelium. It is concluded that CEA, detected in CSF, may originate in mature teratomas, and CEA-positive structures (especially glandular) may differentiate into gastrointestinal tract structures. An examination of serum and CSF levels of CEA may offer additional clues to the diagnosis of intracranial germ-cell tumors.