A 60-year-old patient undergoes an abdominal CT for abdominal pain and is found to have a 2.5 cm homogeneous left adrenal mass. The non-contrast CT shows an attenuation value of 5 Hounsfield units (HU). What is the most likely diagnosis?
- A Adrenocortical carcinoma
- B Pheochromocytoma
- C Adrenal adenoma ✓
- D Adrenal metastasis
Correct answer: C. Adrenal adenoma
Explanation
An attenuation value of 10 HU or less on a non-contrast CT is highly specific for a benign adrenal adenoma, which is typically lipid-rich. Values above 20 HU suggest malignancy or pheochromocytoma. Carcinomas and metastases are usually heterogeneous and have higher HU values.
Reference: Schwartz's Principles of Surgery, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.