An incidental adrenal mass on CT less than 5 cm is most likely which of the following?

An incidental adrenal mass on CT less than 5 cm is most likely which of the following?

• A. Pheochromocytoma
• B. Adenoma
• C. Metastasis
• D. Adrenocortical carcinoma

Answer: (B)

A small incidental adrenal mass is most likely an adenoma because these benign lesions are the most common adrenal incidentalomas, especially when the mass is under about 5 cm. On CT, lipid-rich adrenal adenomas have low attenuation on noncontrast imaging, and if the lesion is small with such low density, it effectively confirms an adenoma without further workup. Pheochromocytoma would be considered if there were clinical clues or biochemical evidence of catecholamine excess. Metastasis and adrenocortical carcinoma are more likely to present as larger, irregular, or invasive tumors rather than a small, well-circumscribed lesion. Thus, the small incidental adrenal mass is best explained as an adenoma.

A small incidental adrenal mass is most likely an adenoma because these benign lesions are the most common adrenal incidentalomas, especially when the mass is under about 5 cm. On CT, lipid-rich adrenal adenomas have low attenuation on noncontrast imaging, and if the lesion is small with such low density, it effectively confirms an adenoma without further workup. Pheochromocytoma would be considered if there were clinical clues or biochemical evidence of catecholamine excess. Metastasis and adrenocortical carcinoma are more likely to present as larger, irregular, or invasive tumors rather than a small, well-circumscribed lesion. Thus, the small incidental adrenal mass is best explained as an adenoma.