F-18 FDG uptake associated with Elastofibroma dorsi.

A patient with a history of colon carcinoma and computed tomography (CT) evidence suggestive of a liver metastasis underwent an F-18 FDG PET scan. The PET scan confirmed a metastasis in the left lobe of the liver. The study also demonstrated bilateral symmetric uptake involving the inferior subscapular regions. Correlation with the previous CT showed this to correspond to bilateral elastofibroma dorsi, which had been prospectively reported on the CT. Elastofibroma dorsi is a rare benign mass consisting of fibroelastic tissue and fat. It has been previously described on PET, CT, ultrasound, and magnetic resonance imaging (MRI). On CT, the masses are of soft tissue density, similar to adjacent musculature, and may contain linear areas of low density secondary to fat. On MRI, elastofibroma dorsi has been shown to have variable enhancement, which may reflect increased vascularity of the lesion. In this case, the masses demonstrated low-grade diffuse F-18 FDG uptake.