Ectopic Cushing's syndrome withperiodic hormonogenesis -a case suggesting apathogenetic mechanism

Summary: Wereport onacaseofectopic Cushing's syndrome duetoathymic carcinoid tumour with periodic hormonogenesis. Periods ofhormonal production averaged 27days. Prior tobilateral adrenalectomy, mean(s.d) values ofACTHandcortisol were202.1 (50.3) pg/ml and46(14.7) ug/dl, ACTHrising to3996±425pg/ml (P< 0.01) andcortisol falling to6.3±1.5jsg/dl (P< 0.01) inthe immediate postoperative period. During thelate postoperative period (2-13 months following surgery) ACTHlevels fell to509.3 (123.8) pg/ml (P< 0.01), butremaining evenhigher (P< 0.01) thanbefore adrenalectomy. Thepattern ofACTHinthepresent casesuggests theexistence ofanegative feedback exerted bythecortisol overtumoral ACTH.