Endocrine Abstracts

Introduction:

Background: Pituitary adenomas can be divided into functioning pituitary adenoma (FPA) and non-functioning pituitary adenoma (NFPA). Pituitary adenomas can also be classified based on their size as microadenoma(<1cm) or macroadenoma (>1cm).

Cases: 1. A 33-year male was admitted with a 4-month history of headaches, generalized aches and pains, weight loss, lethargy, and erectile dysfunction. He was reviewed by the Endocrine team and his hormonal profile showed TSH 2.62, FT4 4.2, FT3 3.7, 9 am cortisol 37, Prolactin 12,000, LH 2.5, FSH 5.4, testosterone 1.7. IGF-1 was 211. He was started on Cabergoline and responded well with normalization of prolactin level to 217. His testosterone level improved alongside LH and FSH. He did not require surgical intervention or Radiotherapy 2. A 63-year-old man presented to Emergency with headaches and visual disturbance. He was reviewed by the neurology team and was found to have bi-temporal hemianopia. CT head revealed a pituitary mass. His past medical history includes erectile dysfunction, gynecomastia, and general lethargy. His blood test revealed a low testosterone level, low LH, and low FSH. Of note, his prolactin level was >100,000. MRI pituitary revealed pituitary macroadenoma with suprasellar extension. He was started on cabergoline with some response and normalization of his visual field. His prolactin level initially dropped to <500 however further rose to >20,000 despite the dose escalation of cabergoline to 10mg weekly. MRI demonstrated significant tumour enlargement and an increase in size. He was treated with external beam radiotherapy, with a reduction in tumour size and an improvement of prolactin to around 3000. The patient was switched to the maintenance dose of quinagolide 300mg once a day and the prolactin level improved to <3000.

Discussion: Most pituitary prolactinomas respond well to dopamine agonists as demonstrated by case 1. The remission rate with cabergoline or bromocriptine is about 70-90%(3,4). Radiotherapy should be considered for patients with pituitary macroprolactinoma which is unresponsive to medical therapy as demonstrated in case 2.

Conclusion: The 1^st line of treatment for pituitary prolactinomas is a dopamine agonist(2,3,4). Radiotherapy should be considered in those patients not responding to medical therapy.