Endocrine Abstracts

Introduction: Large prolactinomas are uncommon and there is limited information on their presentation and progression. In this study we reviewed the presenting features, associated endocrinopathy and the response to treatment.

Methods: 16 patients (aged 20–80 years, 75% male) were identified from our endocrine database as presenting with prolactin >20,000 mU/l between 1985 and 2005.

Results: 75% of patients presented with mass effects (10 visual impairment, 5 headaches, 1 dysphagia). 50% initially presented to Ophthalmology and a further 25% to Neurology/Neurosurgery. Initial median prolactin was 99,000 mU/l (range 22,600 to 444,300 mU/l). Defects of the following axes were seen at diagnosis LH/FSH-Testosterone/Oestrogen (n=10, 63%), TSH-T4 (n=6, 38%), ACTH-Cortisol (n=4, 25%), (50% of patients did not have full adrenal axis assessment prior to treatment). 3 patients underwent surgical decompression prior to starting medical treatment (2 of whom had surgery before prolactin measured). All patients had primary or post-surgical treatment with either carbergoline (63%) or bromocriptine (38%). Median period of follow up was 3 years (range 1 month to 19 years) with latest median prolactin level of 215 (30 to 11,500) mU/l; (excluding 27,570 mU/l in one recent, non-compliant patient). In 75% of patients the latest prolactin was <650 mU/l. Recovery of visual fields was seen in 90% of patients and in the LH/FSH-Testosterone/Oestrogen axis (n=2, 20%), TSH-T4 (n=1, 17%), ACTH-Cortisol (n=1, 25%).

Conclusion: 75 % of patients with prolactin >20,000 mU/l presented with mass rather than biochemical effects. Not all patients had pituitary insufficiency and some surprisingly, even had normal FSH/LH/Testosterone/Oestradiol levels. This study highlights the importance in measuring serum prolactin in all patients with skull-base tumours prior to considering surgery, and for early endocrine review of hyperprolactinaemic patients, as there is generally a good response visually and biochemically to medical treatment.