A 35-year-old male from home with family presented with 12 months of erectile dysfunction and morbid obesity (BMI 69). He was not taking regular medications, with no allergies. He worked as a construction worker and had a 10 pack-year smoking history. On examination, he was not Cushingoid. His blood pressure was 150/90 mmHg with no postural drop. He had bitemporal hemianopia. His testosterone level was 1.2 nmol/L with undetectable gonadotrophins and a prolactin of 73,195 mIU/L. His pituitary panel was otherwise unremarkable. MRI pituitary demonstrated an enhancing lobulated mass measuring 37x33x36 mm with right cavernous sinus and supratentorial extension, and encasement of the right internal carotid artery. He was commenced on cabergoline but his prolactin level failed to fall below 40,000 mIU/L despite up-titrating the cabergoline to 1.5 mg weekly.
Seven months later, he underwent trans-sphenoidal debulking which was limited by the fibrous nature of the tumour. Histopathology showed a pituitary adenoma staining strongly for prolactin. Surgery was complicated by central adrenal insufficiency; he was discharged on hydrocortisone replacement and cabergoline 3.5 mg weekly.
Persistent hyperprolactinaemia and field defects despite high-dose cabergoline led us to trans-cranial debulking of the remaining tumour 11 months following his diagnosis. The fibrous tumour was again difficult to resect. Surgery was complicated by right-sided cranial nerve III palsy. Histopathology again revealed an adenoma staining strongly for prolactin. His cranial nerve palsy did not improve, rendering him unemployed with significant disability. He developed hypothalamic dysfunction including uncontrollable food cravings, thermal dysregulation and lethargy, leading to a further 10 kg weight gain. Given the persistent need for high-dose cabergoline, he received six-week course of stereotactic radiotherapy, with no improvement to date in his prolactin level and visual defects. This case highlights the difficulty of managing treatment-resistant prolactinomas and their negative impact on well-being and quality of life.