Hepatic segmental atrophy and nodular elastosis: imaging features.

Abstract

To evaluate the imaging features of hepatic segmental atrophy and nodular elastosis. In this Institutional review board (IRB)-approved, HIPAA-compliant study, we reviewed imaging features in six cases of histologically confirmed hepatic segmental atrophy (HSA) and nodular elastosis (NE). Retrospective review of ultrasound (US) in 2 patients, computed tomography (CT) in 5 patients, magnetic resonance imaging (MRI) in 4 patients, and positron emission tomography (PET) in 2 patients was performed. Location, size, and attenuation/density/signal intensity of these lesions were evaluated. Clinical presentation and coexistent conditions were also recorded. All six patients were females. Mean age of presentation was 58.3years (range 37-80). A single HSA and NE lesion in each patient was found. The mean size of the lesion was 18 mm (range: 3mm to 36mm). Most lesions were detected incidentally (5/6). On contrast-enhanced single-phase (portal venous) CT, most lesions were hypodense (4/5) and one lesion was hyperdense to fatty liver parenchyma. On MRI, the lesions were iso- to hyperintense on T2-weighted images, T1 hypointense, and hyperintense on diffusion-weighted images (DWI). Three lesions were hypointense on arterial, portal venous, and delayed phases. One lesion occurring in fatty liver appeared hyperintense on all three phases. Gd-EOB-DTPA-enhanced images were available in 2 patients and lesions were hypointense on the 20-min hepatobiliary phase. On PET, two lesions were isometabolic to the background hepatic parenchyma. On ultrasound, one lesion appeared hypoechoic and another lesion isoechoic to hepatic parenchyma. Hepatic segmental atrophy and nodular elastosis is an uncommon benign lesion and can simulate metastases due to variable imaging features. Lack of FDG uptake on PET/CT may be a clue to the benign nature of the lesion and may suggest the possibility of HSA and NE.