Adrenal Nodule Screening

Assess the risk of an adrenal "incidentaloma." This tool uses CT density and physical size to estimate the likelihood of malignancy.

Measure the longest diameter of the mass.
Hounsfield Units from a non-contrast CT scan.
Malignancy Risk Level
Very Low

Typical of a benign lipid-rich adenoma.

Is it Benign or Malignant?

I genuinely believe that the discovery of an "incidentaloma" (a nodule found by accident) can be scary. However, the vast majority of adrenal nodules are benign. We look at two primary factors: **density** and **size**.

Density (HU): Benign adenomas usually contain a lot of fat. Fat has a low density on CT scans. A HU score of less than 10 is almost always a sign of a benign, lipid-rich adenoma.

Size: Nodules smaller than 4 cm are usually benign. As the size increases above 4-6 cm, the risk of malignancy (cancer) or a functional tumor (hormone-producing) increases.

Clinical Action Plan:

  • Low Risk: Usually followed with a repeat scan in 6-12 months.
  • Indeterminate: May require a CT Washout study or MRI.
  • High Risk: May require surgical consultation and hormonal workup.