A case of cyclical Cushing's disease associated with corticosteroidbinding globulin deficiency: a rare pitfall in the diagnosis of Cushing's disease

Watanobe H, Nigawara T, Nasushita R, Sasaki S, Takebe K. A case of cyclical Cushing's disease associated with corticosteroid-binding globulin deficiency: a rare pitfall in the diagnosis of Cushing's disease. Eur J Endocrinol 1995;133:317–9. ISSN 0804–4643 We experienced an extremely unusual combination of Cushing's disease and corticosteroid-binding globulin (CBG) deficiency that has been reported in only one similar case to date. A 53-year-old woman presented at a medical clinic with clinical Cushing's disease. However, her plasma levels of adrenocorticotropin (ACTH) and cortisol were in the normal range. Six months later, during a second visit, a high urinary excretion of 17-hydroxycorticosteroids was found, but plasma ACTH and cortisol levels were normal again. Further investigation revealed a decreased CBG concentration. Free plasma cortisol levels were clearly elevated. Furthermore, the Cushing's disease of our patient was complicated by periodic secretion of ACTH and cortisol, with high or normal outputs of corticosteroids occurring alternately every 1–3 days, which explained the occasionally normal plasma ACTH and cortisol levels. A combination of a decreased serum CBG concentration and periodic secretion of ACTH can be an important pitfall in the diagnosis of Cushing's disease. Hajime Watanobe, Third Department of Internal Medicine, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori 036, Japan