A 15-year-o1d girl was admitted to the New England Medical Center Hospital (NEMCH) for investigation of the hypothalamic-pituitary axis. Four years earlier, an eosinophilic granuloma was discovered in the left mandible and was treated with excision and irradiation (1000 rads). Two years earlier she developed polyuria, and a diagnosis of diabetes insipidus was made at another hospital. She was treated with synthetic lysine vasopressin nasal spray (Diapid) several times a day and noted some symptomatic improvement. Eighteen months before admission, her menstrual periods, which had been normal for the previous 14 months, ceased and she complained of cold intolerance, constipation, and weight gain. She claimed to have grown 0.5 in. over the year prior to admission. She had occasional mild headaches when she did not take her medication but noted no visual disturbances. Family history was unrevealing. Her mother was 61 in. tall.