FRI309 Functional Gonadotrophin Secreting Adenoma With Elevated Testosterone—A Rare Entity

Disclosure: S. Bulchandani: None. S. Syal: None. E. Sloan: None. S.T. Sharma: None. Introduction: Gonadotroph adenomas are a common type of pituitary neuroendocrine tumor (PitNET). However, most do not lead to elevated sex hormone levels(1). Presenting symptoms include headache, visual field deficits, and hypopituitarism.(2-3). Gonadotropin-secreting PitNET leading to high circulating testosterone levels are extremely rare. We report a case of a male patient with a gonadotroph PitNET causing hypersecretion of testosterone. Case Report: 53-year-old male with history of hypertension presented for evaluation of dystonia. He also reported fatigue and an episode of diplopia. He had normal libido and sexual function, no mood fluctuations. MRI of the spine performed for evaluation of dystonia revealed a 2.8 cm sellar mass. MRI Pituitary showed a 31 mm in height by 24 mm in width by 19 mm in depth sellar mass suggestive of a pituitary adenoma with compression of the optic chiasm and extension into the left cavernous sinus. Laboratory evaluation revealed an elevated follicle stimulating hormone level (FSH) of 73.6 mIU/ml (1.6-8.0), luteinizing hormone (LH) 13.3mIU/ml (1.5-9.3), elevated total testosterone of 2176 ng/dl (250-1100) and Free testosterone 367.7 pg/mL (35-155), Sex hormone binding globulin of 68 nmol/L, Alpha subunit of 3ng/mL, prolactin 23 ng/ml (4-15.2), no increase with dilution, TSH 2.24 iIU/ml, free thyroxine level 0.9 ng/dL, and AM Cortisol 6.4 mcg/dl. A Cosyntropin stimulation test revealed adrenal insufficiency and treatment with hydrocortisone was initiated. Ophthalmology evaluation revealed left >right asymmetric bitemporal hemianopia. He underwent transsphenoidal resection of the pituitary tumor. Post-operative laboratory evaluation revealed testosterone level of 43.65ng/dL and FSH of 6.6mIU/ml. Pathology showed a gonadotroph PitNet with diffuse nuclear positivity for SF1 and patchy cytoplasmic positivity for FSH with Ki-67 index of 2-3%. Discussion and Conclusion: Most gonadotropinomas are nonfunctional(2) and clinically present with hypopituitarism and often low or normal sex hormone levels. We present a rare case of gonadotroph PitNet with elevated testosterone levels not associated with a recognizable clinical syndrome of sex hormone excess. The standard therapy for gonadotropin-secreting macroadenomas is trans-sphenoidal surgery.(2-3) Early diagnosis is essential for timely and appropriate management. Presentation: Friday, June 16, 2023