Endocrine Abstracts

A 55-year-old male was referred to the endocrine clinic in October 2006 with a 6 month history of reduced libido, lethargy and right sided retro-orbital headaches. He was otherwise well and not on any medications. Examination revealed gynaecomastia, but no other cutaneous stigmata of endocrinopathies and visual fields were full to confrontational testing.

Prolactin was elevated to 4791 mU/l, and a subsequent MRI confirmed a macroadenoma measuring 8×11 mm, with no compression of the optic chiasm. The rest of the anterior pituitary profile was normal, including IGF1. Carbergoline treatment at a dose of 250 μg twice per week provided a good biochemical and clinical response. In view of new symptoms (skin thickening and a change of ring size), further endocrine testing was performed, which demonstrated a raised IGF1, and acromegaly was confirmed with glucose suppression testing. MRI scans showed no change in the original adenoma. Subsequent monitoring of his IGF1 rising levels and he underwent hypophysectomy, with glucose suppression testing post-operatively confirming cure.

There have been a few reports of the development of co-secretion in patients with initial prolactin-only secreting adenomas. Annual screening has been suggested although this is expensive, and may not always be warranted. An open mind to the development of acromegaly should be kept particularly in light of new symptoms in patients with prolactinomas.