Metyrapone-responsive ectopic ACTH-secreting pheochromocytoma with a vicious cycle via a glucocorticoid-driven positive-feedback mechanism.

Metyrapone-responsive ectopic ACTH-secreting pheochromocytoma with a vicious cycle via a glucocorticoid-driven positive-feedback mechanism. Endocr J. 2018 May 15;: Authors: Inoue M, Okamura K, Kitaoka C, Kinoshita F, Namitome R, Nakamura U, Shiota M, Goto K, Ohtsubo T, Matsumura K, Oda Y, Eto M, Kitazono T Abstract In ectopic ACTH-secreting pheochromocytoma, combined ACTH-driven hypercortisolemia and hyper-catecholaminemia are serious conditions, which can be fatal if not diagnosed and managed appropriately, especially when glucocorticoid-driven positive feedback is suggested with a high ACTH/cortisol ratio. A 46-year-old man presented with headache, rapid weight loss, hyperhidrosis, severe hypertension and hyperglycemia without typical Cushingoid appearance. Endocrinological examinations demonstrated elevated plasma and urine catecholamines, serum cortisol and plasma ACTH. Moreover, his ACTH/cortisol ratio and catecholamine levels were extremely high, suggesting catecholamine-dominant ACTH-secreting pheochromocytoma. Computed tomography revealed a large right adrenal tumor. 18F-FDG positron emission tomography showed uptake in the area of the adrenal tumor, while 123I-metaiodobenzylguanidine scintigraphy showed no accumulation. His plasma ACTH level paradoxically became elevated after a dexamethasone suppression test. After metyrapone administration, not only serum cortisol but also plasma ACTH levels were exponentially decreased al...
Source: Endocrine Journal - Category: Endocrinology Tags: Endocr J Source Type: research