Endocrine Abstracts

A 33 year old male presented with a two year history of fatigue, headaches, loss of libido, insomnia, depression and hypertension. On examination, he was floridly Cushingoid with central obesity, proximal muscle weakness and purple striae. A bilateral temporal, superior quadrantanopia was noted on formal perimetry. Investigations revealed markedly elevated prolactin levels at 56560mIU/L, hypogonadotropic hypogonadism and secondary hypothyroidism. He also had elevated urinary cortisols at 2143 nmol/24 hrs (50–300), failure of suppression on low dose dexamethasone suppression test at 621 nmol/l, and a raised ACTH at 68 ng/L (<50). Pituiary MRI demonstrated a 3 × 2 cm cystic pituitary mass impinging on the optic chiasm. Inferior petrosal sinus sampling confirmed pituitary source of Cushings. CT chest and abdomen demonstrated no evidence of adrenal mass or source of ectopic ACTH, and bone densitometry confirmed severe osteoporosis. He was started on cabergoline 0.25 mg twice a week, with a fall in his prolactin levels to 806 mIU/L. However, his mean cortisol levels on a day curve also dropped from 727 to 500 at one week. The dose of cabergoline was then titrated upwards to 1 mg twice weekly, and his latest day curve mean is 155 nmol/l with normalisation of UFCs to 74 nmol/24 hrs and he now suppresses to 102 nmol/l on repeat low dose dexamethasone testing. His symptoms and signs have melted away, his antihypertensive drugs been stopped and he is now back at work full time. Serial MRI scans have also shown progressive reduction in size of tumour. We believe this to be the first reported case of a pituitary macroadenoma co-secreting prolactin and ACTH. This case is also unique in demonstrating such a dramatic response of his Cushing’s disease to first line cabergoline therapy.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Summary of investigations

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.