Endocrine Abstracts

35-year-old lady, has a background of Hypertension, oophorectomies for ovarian cancer and previous 2 IVF attempts, referred to endocrinology with three-week history of blurred vision, bitemporal hemianopia and large pituitary mass on MRI Upon assessment, she reported visual disturbance and intermittent headache. She has no periods which is expected with the history of oophorectomy, but she denied galactorrhoea or any symptoms suggestive of pituitary hormone excess or deficiency. Examination was unremarkable apart from the bitemporal hemianopia

Investigations: Prolactin 47004mU/l(102-496mU/l), Low FT4 was 9.9 pmol/l(12.0 - 22.0) with inappropriately normal TSH2.2mU/l(0.27 - 4.20). Pituitary profile otherwise unremarkable. MRI pituitary revealed large pituitary mass measuring 45x52x25mm with invasion of the sphenoid and clivus, right cavernous sinus, and large suprasellar extension encircling the optic chiasm. A diagnosis of giant, extensive macroprolactinoma was made, and she had genetic tests done (MEN1, RET, CDC73, CDKN1B and AIP) which came back negative

Treatment course: the case was discussed in the pituitary MDT. The patient was started on Bromocriptine initially and then switched to Cabergoline. Her prolactin dropped to 30080 in 6 weeks and continued to drop slowly with the titration of cabergoline. She showed a good tolerance to cabergoline and stability in terms of her symptoms. On the maximum cabergoline dose her prolactin levels ranged from 14532mU/L-21480mU/land her MRI scan 3 months and 6 months after treatment showed no measurable change in size of the large pituitary adenoma suggesting a weak response to treatment. Accordingly, treating team though that with the risk of tumour progression during pregnancy, surgery would be better option compared with medical treatment alone. With patient agreement transsphenoidal surgery with debulking done, which complicated by CSF leak post-operatively alongside infection requiring 3-week admission. She recovered well afterward with subjective improvement in her peripheral visual field. Prolactin level drop from 21480mU/lpreoperative to 4646mU/lpostoperative. Further discussions about off licence use of cabergoline 5 mg per week aiming for further drop in prolactin level was agreed by the patient. Post Operative glucagon stimulation test done which showed adequate cortisol response and Growth hormone deficiency that required a regular follow-up. She was successfully weaned off steroid and currently she is awaiting IVF treatment.

Conclusion: Late diagnosis of prolactinoma in our case could be attributed to the absence period secondary to oophorectomy. Management of cabergoline-resistant prolactinomas is challenging and surgical debulking can improve the outcome. Off licence use of high dose cabergoline remain controversial.