An Incidental Pituitary Adenoma with intact LH Hypersecretion

Objective: We present a relatively uncommon case of gonadotroph cell adenoma with elevated FSH and intact LH resulting in supranormal free and total testosterone. Case Presentation: A 52 year old Caucasian male with a history of hypertension, diabetes mellitus, normal pubertal and fertility history presented with head trauma due to assault by his son. He did not have any focal neurological deficit on initial presentation. CT of the head incidentally showed a large rounded mass measuring 4.1 x 4.3 x 6.3 cm. Brain MRI showed a large sellar and suprasellar mass extending to the right anterior cranial fossa with surrounding vasogenic edema. Imaging was most suspicious for a pituitary macroadenoma. His initial labs were FSH 58.3 mIU/mL (0.9-15), LH 9.1 mIU/mL (1.5- 9.3), prolactin 25.3 ng/mL (1.8-14.4), free testosterone 29 ng/dL (7.2-24) and total testosterone 837 ng/dL (193-740). LH was confirmed to be intact by immunoassay. TSH and ACTH were normal, but GH was 0.1 ng/mL (0-6.0) and IGF-1 was 59 ng/mL (87-238). The patient underwent image guided transnasal, transsphenoidal resection of the tumor, right frontotemporal craniotomy and orbital osteotomy for resection of the supratentorial component of the tumor. Pathology returned as pituitary adenoma with expression of only FSH and LH. His postoperative course was complicated by intracranial hemorrhage and Enterobacter encephalitis, eventually requiring tracheostomy and PEG tube placement. Post resection labs showed L