MRI images demonstrate a large hypervascular mass in the left abdomen which arises from the anterior inferior pole of the left kidney. The mass demonstrates multifocal regions of macroscopic and microscopic fat with central regions of increase T1 signal suggestive of internal hemorrhage. Post-contrast arterial phase images demonstrate that the mass is largely supplied by a single left main renal artery. Additionally, the mass appears to be drained by venous collaterals, which are incompletely included in the field of view.
(Three hepatic lesions were also noted, two of which demonstrate classic features of FNH. A third arterially enhancing lesion in the hepatic segment VII was indeterminate, though based on continued imaging FU, was presumed to represent atypical FNH).