Endocrine Abstracts

Introduction: Typically, patients with a microprolactinoma will have serum prolactin level between 2,000-4,000mIU/l. The primary goal of treatment is to normalise prolactin level and thereby improve symptoms associated with a raised prolactin. Dopamine (D2) agonists are the main stay of treatment with some patients unable to tolerate dopamine agonists rather than being resistant to the medication.

Case report: A 26-year-old lady with a history of anxiety and depression, hypersomnia, obesity class 3, PCOS, presented with galactorrhoea and secondary amenorrhoea. Her prolactin level was 1670 mU/l, with suppressed gonadotrophins (Table:1) She was on venlafaxine, modafinil. MRI pituitary in 2018 revealed 5x6 mm pituitary microadenoma. In 2018, she was commenced on Cabergoline and subsequently Bromocriptine, but unable to tolerate standard doses. She continued to have symptomatic hyperprolactinaemia despite discontinuation venlafaxine. Later she was restarted on Duloxetine for her other medical conditions. Repeat pituitary MRI in 2019 time revealed slight increase in size of the adenoma measuring 1.34 cm X 1.24 cm, with no compression of the optic chiasm. Due to her poor response and intolerance to D2 blockers she was initiated on Lanreotide 30 mg monthly injections in January 2021 (prolactin 4,558)., In December 2021, prolactin fell to 1,843 (>50% reduction). Given an insufficient response Lanreotide was discontinued and prolactin rose in January 2022 (figure-1).

Conclusions: Dopamine agonist intolerance poses a management challenge with Prolactinomas. There is insufficient evidence with Somatostatin receptor agonists.