Introduction: Functioning gonadotroph adenomas (FGAs) are very rare tumours secreting biologically active gonadotropins. In males, typically, FSH levels are elevated, whereas LH and testosterone are variable. Herein, we present three males with elevated, normal or low testosterone at diagnosis.
Cases: Case 1:42-year-old man with two-year history of visual impairment. Bitemporal hemianopia was confirmed. Imaging showed macroadenoma compressing optic chiasm. He had increased gonadotropins [FSH:88.3 IU/l (1.512.4), LH:26.2 IU/l (1.78.6)], increased testosterone [82.4 nmol/l (727)], normal SHBG [24.8 nmol/l (14.548.4)], hyperprolactinaemia, ACTH/ TSH deficiency. He did not report manifestations related with high testosterone but he had polycythaemia. Pituitary surgery was performed; pathology: adenoma with focal positivity for FSH and diffuse positivity for LH. Haemoglobin normalised post-operatively.
Case 2: 39-year-old man with a few months history of headaches and bitemporal hemianopia. Pituitary macroadenoma with chiasmal compression was found. He had increased FSH [45 IU/l (1.512.4)], low LH [1.1 IU/l (1.78.6)], normal testosterone [8.1 nmol/l (727)], normal SHBG (20.6 nmol/l) and hyperprolactinaemia. Pituitary surgery was performed; pathology: adenoma with mild focal FSH and LH expression.
Case 3: 25-year-old man with 6-months history of visual deterioration. Left temporal hemianopia was confirmed. Imaging revealed macroadenoma distorting optic nerve. He had increased FSH [49.3 IU/l (211)], normal LH [1.3 IU/l (18)], low testosterone [4.7 nmol/l (727)], normal SHBG (24.8 nmol/l), hyperprolactinaemia, ACTH deficiency. Bilateral testicular enlargement was noted. Pituitary surgery was performed; pathology: adenoma with scattered FSH positivity.
Discussion/conclusions: Our cases highlight the wide spectrum of LH and testosterone concentrations in men with FGAs, mainly depending on hypersecretion of intact, biologically active LH and potential mass effects to normal gland. Co-secretion of intact FSH and LH is extremely rare and distinct clinical manifestations of high testosterone have not been, as yet, described in these patients.