Hypermetabolic adrenal adenoma

Contributed by: Ed Boas

The hypermetabolic left lower lobe lung mass is a mixed squamous cell carcinoma and adenocarcinoma.

There is also a left adrenal nodule.  This measures under 10 Hounsfield units, which is consistent with a lipid rich adrenal adenoma.  However, it is also hypermetabolic (SUV of 8.3), which is not consistent with an adenoma.

MRI again shows the left adrenal nodule, with signal dropout on the out of phase image, again consistent with a lipid rich adenoma.

The follow up CT resolves the discrepancy.  There is a growing adrenal metastasis next to the adrenal adenoma.

Pearls:

If an adrenal nodule appears to be an adenoma based on CT or MRI, but it is hypermetabolic on PET, there may be a small adrenal metastasis near the adenoma.