Phaeochromocytoma and ACTH-dependent cushing's syndrome: tumour crf secretion can mimic pituitary cushing's disease.

INTRODUCTION: 10% of corticotrophin (ACTH)-dependent Cushing's syndrome arises from secretion by extrapituitary tumours, with phaeochromocytoma implicated in a few cases. Ectopic secretion by phaeochromocytoma of corticotropin-releasing hormone (CRF), with secondary corticotroph hyperplasia, is even rarer, with only five cases in the literature hitherto. However, such cases may be classified as 'ectopic ACTH' due to incomplete verification. CLINICAL CASES: We describe three patients with phaeochromocytoma and ACTH-dependent Cushing's syndrome in whom biochemical cure was achieved following unilateral adrenalectomy. Although unable to access a validated CRF assay within the timeframe for sample storage, we nevertheless inferred CRF secretion in 2 of 3 cases by tumour immunostaining (positive for CRF; negative for ACTH), supported in one case by pre-operative inferior petrosal sinus sampling (IPSS) indicative of pituitary ACTH source. Both cases were characterized by rapid postoperative wean off glucocorticoids, presumed to reflect the pituitary stimulatory-effect of CRF outweighing central negative feedback inhibition by hypercortisolaemia. By contrast, the tumour excised in a third case exhibited positive immunostaining for ACTH - negative for CRF - and postoperative recovery of hypothalamic-pituitary-adrenal axis took significantly longer. DISCUSSION: Ectopic CRF production is biochemically indistinguishable from ectopic ACTH secretion, except that IPSS mimics pituitary Cushing's disease and cortisol dynamics may normalize rapidly postadrenalectomy. CRF secretion can be inferred through tumour immunohistochemistry, even if no CRF assay is available. Unrecognized phaeochromocytoma ACTH secretion may underpin some cases of cardiovascular collapse postadrenalectomy through acute hypocortisolaemia. Despite advances in phaeochromocytoma genetics since previous reports, we were unable to identify somatic DNA defects associated with either ACTH or CRF secretion.

Management of cystic tumours of the pancreas.

BACKGROUND: Cystic tumours of the pancreas account for 5% of pancreatic neoplasms and are frequently misdiagnosed as pancreatic pseudocysts. The authors' experience of managing these tumours is presented here, highlighting the clinical presentation, diagnostic difficulties and operative treatment. METHODS: This is a retrospective study of all patients diagnosed to have cystic tumours of the pancreas treated at The Mater Hospital, during a 5-year period from 1997 to 2002. Literature was reviewed and guidelines for the management of these tumours have been outlined. RESULTS: Seven patients with cystic pancreatic tumours were treated over this time-period. All patients were women with a median age of 40. Two of these patients were initially diagnosed as having pseudocysts and were treated elsewhere by cystgastrostomy. The tumour was resected in all patients. All but one was benign. At follow up, ranging from 13 to 66 months, all patients were alive and well. CONCLUSIONS: Cystic tumours of the pancreas are uncommon and generally slow growing. It is important not to assume that a cystic lesion in the pancreas, especially in middle-aged women, is a pseudocyst. Satisfactory surgical resection may be possible even after previous operative procedures on the pancreas. Prognosis after resection remains good.