Food-dependent Gushing's syndrome of long standing with mild clinical features

History and clinical findings: A 40-year-old woman complained of weight gai n for 10 years. Because of this, she yearly went on a excessive weight redu ction diet with weight loss of up to 12 kg. Nevertheless, a total weight ga in of 15kg as well as changing degrees of hypertension, muscular weakness a nd severe depression were registered during this long period. For 5 years e cchymosis and for 2 years oligomenorrhoea as well as oedema had become evid ent. Recently large macronodular adrenal glands were found on routine abdom inal ultrasound. At the time of clinical investigation early this year she presented with relatively mild Gushing features, such as moon face, central obesity, hirsutism, ecchymosis and hypertension. Investigations: Endocrine testing demonstrated suppressed plasma ACTH, low to normal plasma cortisol after overnight fasting and an inverse diurnal rh ythm. During 24 hours of fasting plasma cortisol levels and free urinary co rtisol excretion were within normal range, but highly elevated under normal food intake. Plasma cortisol levels increased dramatically in response to a lipid-rich meal (5.6-fold), to a protein-rich meal (6.6-fold) and to oral glucose (3.7-fold). Increases in plasma cortisol were closely correlated t o increases of gastric inhibitory polypeptide (GIP) concentrations. Subcuta neous injection of octreotide completely inhibited the plasma cortisol and GIP response to oral glucose. Plasma ACTH and cortisol levels did not incre ase after CRH administration, but fasting plasma cortisol promptly increase d after ACTH stimulation. Non-fasting plasma cortisol levels and free urina ry cortisol excretion were not suppressed by high doses of dexamethasone. A bdominal computed tomography showed macronodular enlargement of both adrena l glands. Treatment and course: The patient underwent bilateral adrenalectomy. Postop eratively, she was treated with replacement doses of hydrocortisone and flu drocortisone. All Gushing features have regressed, a normal menstrual cycle and normal plasma ACTH concentrations have become evident. Conclusion: This case report not only presents a very rare cause of Gushing 's syndrome - food-dependent or gastric inhibitory peptide (GIP)-dependent hypercortisolism - but it also demonstrates a special course of this diseas e of relatively long duration. Severe adrenal hyperplasia contrasted with m ild clinical symptoms obviously caused by frequent periods of weight reduct ion diet. Considering this moderate clinical course it might well be that f ood-dependent hypercortisolism is more frequent than supposed, but not diag nosed owing to relatively mild clinical symptoms.