Case Report: Adrenocortical adenoma harboring atypical subclinical Cushing's syndrome with dehydroepiandrosterone sulfate transferase and cytochrome b5 expression in tumor cells.

Subclinical Cushing's syndrome (SCS) is frequently encountered during the clinical evaluation of adrenal incidentalomas and is typically associated with reduced levels of serum dehydroepiandrosterone sulfate (DHEA-S). Cytochrome b5 is a component of the electron transfer system that enhances the activity of 17, 20-lyase relative to that of 17a-hydroxylase. Therefore, tumors harboring cytochrome b5 might be associated with dehydroepiandrosterone sulfotransferase (DHEA-ST) expression, resulting in unsuppressed serum DHEA-S levels. Here, we reported the first case of SCS with elevated serum DHEA-S levels in an incidentally detected adrenocortical adenoma showing immunohistochemical positivity for both cytochrome b5 and DHEA-ST.