Adrenal Cushing syndrome in a patient with corticosteroid-treated asthma and worsening diabetes mellitus.

A 55-year-old woman with poor diabetic control and a long history of corticosteroid-treated asthma was admitted. Hypertension and dyslipidaemia developed 9 and 6 years ago, respectively, and both were poorly controlled. Three years ago, her asthma control improved, and oral/intravenous steroids were switched to inhalers. Around this time, she was diagnosed as diabetes mellitus and heavily treated with insulin and other drugs thereafter. Physical examination showed central obesity, moon face appearance, abdominal striae and purpura. Endocrinological examination revealed suppressed adrenocorticotropic hormone, but unsuppressed endogenous cortisol levels. Right adrenal mass with isotope uptake revealed by CT scan and I-adosterol scintigraphy was compatible with cortisol-producing adenoma, leading to the diagnosis of adrenal Cushing syndrome. A history of corticosteroid usage sometimes prevents us from the timely detection of endogenous cortisol excess. Our current case tells us a lesson of the importance of suspecting non-iatrogenic causes of Cushing syndrome even in patients heavily treated with corticosteroids.