A case of sparsely granulated growth hormone cell adenoma associated with lymphocytic hypophysitis

Lymphocytic hypophysitis is in itself rare and usually occurs in the postpartum period or the last trimester of pregnancy. It has not been described in combination with a pituitary tumor. A twenty-two year old woman, who had never been pregnant, presented with a history of nine months amenorrhea and spontaneous galactorrhea. She was not taking any medication and had never used oral contraceptives. Physical examination was unremarkable except that whitish fluid could be expressed from both breasts. Her visual fields were normal. Her serum PRL levels was high at 105.7 micrograms/l and increased to 138.4 micrograms/l at 60 minutes in a triple bolus test. GH values were normal and there was no evidence of overproduction of other pituitary hormones. CT scan showed an intrasellar mass with suprasellar extension. A tumor was selectively removed transsphenoidally. Morphologic examination revealed a clinically silent sparsely granulated growth hormone cell adenoma with lymphocytic infiltration of the adjacent pituitary tissue. Postoperatively her menstrual periods resumed and she conceived despite a slightly elevated PRL level. Three months after an uneventful pregnancy and full term delivery her PRL level was 69.9 micrograms/l and increased to 102.2 micrograms/l at 60 min. Basal GH and cortisol levels were normal. She remains well without replacement fourteen months after delivery. This case is of interest because it is the first reported simultaneous occurrence of a pituitary adenoma and lymphocytic hypophysitis and also because the hypophysitis preceded her first pregnancy.