Biochemically detectable pheochromocytoma

Unenhanced (A) and enhanced (B) axial CT images of an incidentally discovered 4.5 × 3.8 × 3.5 cm left adrenal mass (arrows). On the unenhanced image, the CT attenuation was 25 HU and diagnostic of a lipid-poor adrenal mass. With contrast administration, the adrenal mass was shown to be vascular and partially cystic (B), enhanced inhomogenously, and had slow contrast washout (<50% at 10 minutes). Biochemical evaluation was diagnostic of a noradrenergic pheochromocytoma with 24-hour urine normetanephrine of 4319 mcg (normal <900 mcg) and metanephrine of 250 mcg (normal <400 mcg).