Endocrine Abstracts

Background: Gonadotroph adenomas are usually clinically non-functioning and hypersecretion of FSH or LH is unusual, and no distinct hormone-dependent clinical phenotype is present. Positive immunostaining for nuclear transcription factor SF1 is usually sufficient to diagnose gonadotroph adenoma.

Case History: A 37-year-old lady with Asian background presented with tiredness, headaches, weight gain, poor sleep, secondary amenorrhea and infertility for 2 years. She previously conceived twice with one live birth and a miscarriage. She had a past medical history of PCOS.

Examination: She had no galactorrhea or visual field defects. Rest was unremarkable. Weight 87.2 kg Height 162 cm -BMI 33.2 kg/m².

Investigations: FSH -3.6 IU/l (2.5-10.2 IU/l). LH-1.1 IU/l (1.9-12.5) with increased FSH/lH ratio in the setting of high oestradiol of 2156 pmo/l, testosterone 2.7 nmol/l(0.5-2.5 pmo/l), free testosterone 59 pmo/l (10-50) and prolactin >4237 mIU/l (102-496 mIU/l). TSH and Cortisol levels-normal. Serum prolactin was undetectable 2 weeks after commencing cabergoline therapy, consistent with stalk effect. US Pelvis-Both ovaries had normal ultrasound appearances. No cysts or mass seen in pelvis. MRI Head-Large sellar/suprasellar mass, measuring 25 x19mm, partly encasing the right internal carotid artery. Some radiological compression of the chiasm.

Management: Under the combined endocrine and neurosurgery pituitary multidisciplinary team, trans-sphenoidal surgery was performed without post-operative complications. She was commenced on Hydrocortisone 10/5/5 mg, which was discontinued after a normal response to an insulin stress test. Histology result showed a predominant hormone negative pituitary adenoma with variably intense nuclear positivity for SF1 transcription factor and a few FSH and pan α-subunit positive cells, consistent with a gonadotroph adenoma.

Conclusion: Gonadotroph adenoma should be considered in the differential diagnosis of patients harboring pituitary adenoma with reproductive dysfunction. Trans-sphenoidal resection is the initial treatment of choice although recurrence remains a significant possibility long-term and continued surveillance is essential.