Since the patient had been exposed to 175 R of whole-body gamma radiation, the possible influence of such exposure on the development of the pitui- tary adenoma must be considered. Intracranial tumors have been reported, possibly associated with radiation exposure (107,108,197), but these were mainly gliomas, meningiomas, neurinomas, etc., and not pituitary adenomas. Ina study of the Japanese exposed to the A-bomb, Seyama et al. (109) reported an increase in certain types of intracranial tumors in a group exposed to 100 R or more, but no increase in pituitary adenomas. Therefore, the association of radiation exposure with the development of the pituitary tumor in this patient does not seem likely. ~ 52 -