Should we be using a cut off of 20 rather than the traditional 10 Hounsfield units to distinguish between benign and malignant adrenocortical tumors on imaging?

A higher CT density cut-off of 20 (even 30 in most cases) may be used to rule out ACC. However, some metastatic lesions can have a non-contrast CT density between 10 and 20 HU.

A combination of a tumor size <4 cm and CT density <20 HU is pretty good in excluding almost all malignant lesions.

In at least one high-risk population, a HU cutoff of less than 10 has been shown to have a sensitivity of 100% for excluding malignancy and Pheo. Over 10, I do not feel comfortable excluding it based on one imaging study alone, and would be more likely to order imaging followup (or other, more aggre...