Characterization of adrenal incidentaloma discovered with tomography. General review

The detection of an incidentaloma at abdominal Computed Tomography (CT), except CT features that permit a specific diagnosis (hemorrhage, myelolipoma or cyst), become a problem to differentiate adenomas from "non adenomas" (primary or secondary malignancy) incidentalomas. A density of ten Hounsfield units or less with a nonenhanced CT is a feature of benign incidentaloma (essentially lipid-rich adrenal adenomas). There are two limitations of this characterization: incidentalomas initially detected at enhanced CT and lipid-poor adrenal adenomas. The relative enhancement washout on enhanced CT, by using a threshold of 50% washout, permit then to characterized as adenomas or "non adenomas" incidentalomas on a 10-minute-delayed enhanced CT. Limitations of this characterization are only for benign pheochromocytomas and atypical adrenal cortical carcinomas.