Gonadotroph adenoma in multiple endocrine neoplasia type 1

To describe a case of an in vivo follicle-stimulating hormone (FSH)-secreting gonadotroph adenoma in a man with multiple endocrine neoplasia type 1 (MEN 1) syndrome.

We present a retrospective case description and a discussion of the related literature.

A 48-year-old man had progressively deteriorating visual acuity and bitemporal hemianopia, found to be attributable to a macroadenoma encircling both carotid arteries and compressing the optic chiasm. His libido and erectile function had been reduced for 2 years. The serum FSH level was substantially elevated at 31.1 IU/L (reference range, 1 to 10); alpha-subunit was elevated at 2.25 IU/L (reference range, 0.09 to 0.4); luteinizing hormone was normal at 4 IU/L (reference range, 1 to 10); total testosterone was low at 6.8 nmol/L (reference range, 9.5 to 35); and prolactin was slightly increased at 433 mU/L (reference range, 50 to 300). Transsphenoidal hypophysectomy was performed. Pituitary histopathologic examination showed a tumor with cytoplasmic granular FSH immunoreactivity. The patient had undergone parathyroidectomy for primary hyperparathyroidism 2 years before the current intervention. A family history of endocrine neoplasia was obtained of one sibling with a nonfunctioning pituitary adenoma, another sibling who had died of pancreatic carcinoma, and a third sibling, along with her son, who has primary hyperparathyroidism. Performance of genetic testing for MEN 1 revealed a nonsense mutation--R460X (nt7605C>T)--located on exon 10 of the MEN1 gene.

We report an unusual case of clearly high circulating immunoreactive FSH due to a functioning FSH-secreting gonadotroph adenoma in a man with the MEN 1 syndrome.