Characterization of hepatic adenoma with atypical appearance on CT and MRI by radionuclide imaging.

The appearance of hepatic adenomas on CT and MRI are highly variable because of their varied histopathology, and images of adenomas are at times indistinguishable from those of other hepatic tumors. The authors present two patients with hepatic adenomas with extremely atypical CT and MRI manifestations demonstrating a "nodule-in-nodule" appearance. Radionuclide imaging in both patients showed decreased Ga-67 uptake in the adenomas compared to normal liver, negative colloid (Tc-99m phytate) uptake in the adenomas, and early uptake and subsequent retention of Tc-99m PMT. This correctly characterized the unique histopathologic features of the resected tumors. Radionuclide imaging using a combination of radiotracers may play an important role in aiding the diagnosis of this rare benign tumor, despite variable CT and MRI appearances.