Endocrine Abstracts

A 54-year-old female presented to her GP with a 9-year history of poorly controlled hypertension (requiring five drugs) and type 2 diabetes mellitus, associated with central weight gain, low mood and poor wound healing. On examination she had clinical evidence of glucocorticoid excess. Cushing’s syndrome was confirmed on low dose dexamethasone suppression testing (2+0 cortisol 857 nmol/l, 2+48 cortisol 346 nmol/l). Cushing’s day curve demonstrated loss of circadian rhythm, with a mean cortisol of 702 nmol/l. Serum ACTH was detectable at 45 ng/l and inferior petrosal sinus sampling confirmed pituitary-dependent Cushing’s disease. Pituitary MRI imaging demonstrated a markedly enlarged, predominantly empty pituitary fossa, with a sliver of tissue on the left hand side, raising the possibility of a previous macroadenoma which had auto-infarcted. Adrenal imaging showed bilateral marked nodular hyperplasia. The relative values of the ACTH and cortisol levels was thought to indicate that the adrenals had developed a degree of semi-autonomy. Medical therapy was commenced with 8 hourly metyrapone 750, 750, 1000 mg. The patient has been referred for conventional fractionated external beam radiotherapy, in light of the fact that trans-sphenoidal surgery would be unlikely to be curative and highly likely to result in a CSF leak due to the anatomy. It is likely she will require unilateral or bilateral adrenal surgery in the future. This case demonstrates that long-term ACTH stimulation of the adrenal glands can result in significant adrenal hyperplasia with autonomy and highlights the potential value of adrenal imaging, even in cases of proven ACTH-dependent pituitary disease.