A rare cause of Cushing's syndrome demonstrates analytical discrepancies between the Roche E170 and Bayer Centaur testosterone assays.

The initial biochemical investigations of a female patient with suspected Cushing's syndrome revealed abnormal endocrine results, including a marked elevation of serum testosterone. Overnight and low-dose dexamethasone suppression tests confirmed the diagnosis of Cushing's syndrome. Imaging investigations revealed an appearance compatible with adrenocortical carcinoma with metastases in the lungs and liver.