A 49 year old male, known to suffer from hypertension, was bein investigated for recurrent occipital headaches. An MR Brain showed a 2.4 cm×2.8 cm×4.2 cm sellar mass with suprasellar extension, optic chiasm compression, infrasellar extension with erosion into the sphenoidal sinus, lateral extension into the left sided cavernous sinus and further extension through the cavernous sinus into the parietal lobe. The tumour contained some cystic areas and moderately enhanced with contrast. Pituitary function tests results showed: FSH 17.3 U/l (0.111), LH: 15.1 U/l (0.87.6), Testosterone 7 nmol/l (4.426.5) whilst thyroid function tests, cortisol, GH, IGF1 and prolactin were normal. The patient complained of bilateral gynaecomastia, testicular swelling and tenderness, mild lethargy and occasional nausea in the mornings. He denied visual disturbances. An ultrasound testes confirmed testicular enlargement with a right testicular volume of 21 ml and left testicular volume of 29 ml. He underwent transsphenoidal surgery for removal of the giant macroadenoma in September 2018. Histology showed a pituitary adenoma with strong diffuse LH and patchy FSH expression. Ki67 proliferative index was low (less than 3%). Post operatively FSH was 8 U/l, LH 4.7 U/l, Testosterone 4.4 nmol/l. The rest of his pituitary function tests were normal. Gynaecomastia and testicular symptoms significantly improved post operatively. His post-operative MR scan showed a small residual tumour mainly in the left cavernous sinus.
Discussion: Functional gonadotropin secreting adenomas are a rare entity with only few published cases in middle aged males. They are difficult to diagnose as hormonal secretion is erratic. They rarely cause a clinical syndrome. Excess FSH secretion results in testicular enlargement due to the increase in length of the seminiferous tubules. LH and testosterone levels can be low, normal or high. First line treatment is surgical resection of the adenoma. Regular clinical, biochemical and radiological follow up must be ensured.