Which imaging feature is considered suspicious for an adrenal incidentaloma?

Which imaging feature is considered suspicious for an adrenal incidentaloma?

• A. Size <2 cm and homogeneous enhancement.
• B. Size around 3 cm with smooth margins.
• C. Size >4 cm, irregular margins, heterogeneous enhancement, or invasion.
• D. Calcification without size change.

Answer: (C)

Imaging helps tell benign adrenal adenomas from malignant lesions by looking at size and how the lesion appears with contrast. Benign adenomas are usually small and uniform, often with low attenuation on CT due to fat and with homogeneous enhancement. When a lesion is larger than about 4 cm, or shows irregular margins, heterogeneous enhancement (areas of necrosis or hemorrhage), or invasion into adjacent tissues, these features raise concern for malignancy such as adrenal cortical carcinoma or metastasis. Calcification can occur but isn’t by itself a definitive sign of cancer. So the pattern of a lesion over 4 cm with irregular margins, heterogeneous enhancement, or invasion is the most suspicious.

Imaging helps tell benign adrenal adenomas from malignant lesions by looking at size and how the lesion appears with contrast. Benign adenomas are usually small and uniform, often with low attenuation on CT due to fat and with homogeneous enhancement. When a lesion is larger than about 4 cm, or shows irregular margins, heterogeneous enhancement (areas of necrosis or hemorrhage), or invasion into adjacent tissues, these features raise concern for malignancy such as adrenal cortical carcinoma or metastasis. Calcification can occur but isn’t by itself a definitive sign of cancer. So the pattern of a lesion over 4 cm with irregular margins, heterogeneous enhancement, or invasion is the most suspicious.