Ectopic Cushing's syndrome with periodic hormonogenesis - A case suggesting a pathogenetic mechanism

Abstract

We report on a case of ectopic Cushing's syndrome due to a thymic carcinoid tumour with periodic hormonogenesis. Periods of hormonal production averaged 27 days. Prior to bilateral adrenalectomy, mean (s.d) values of ACTH and cortisol were 202.1 (50.3) pg/ml and 46 (14.7) μg/dl, ACTH rising to 3996 ± 425 pg/ml (P >0.01) and cortisol falling to 6.3 ± 1.5 μg/dl (P>0.01) in the immediate postoperative period. During the late postoperative period (2-13 months following surgery) ACTH levels fell to 509.3 (123.8) pg/ml (P >0.01), but remaining even higher (P>0.01) than before adrenalectomy. The pattern of ACTH in the present case suggests the existence of a negative feedback exerted by the cortisol over tumoral ACTH. © The Fellowship of Postgraduate Medicine, 1987.