Central scars in primary liver tumors: MR features, specificity, and pathologic correlation.

Tumor scars were identified at pathologic study and magnetic resonance (MR) imaging in ten of 17 (59%) primary liver tumors (nine hepatocellular carcinomas, four giant hemangiomas, two hepatic adenomas, and two cases of focal nodular hyperplasia). Histopathologic examination revealed three types of scar tissue. Inflammatory scars (n = 4), with edema, necrosis, hypercellularity, and loose fibrous tissue, appeared hypointense relative to liver on T1-weighted images and hyperintense on T2-weighted images. Vascular scars (n = 3), predominantly composed of vascular channels traversing collagenous tissue, showed MR features similar to those of inflammatory scars. Collagenous scars (n = 3) appeared hypointense relative to liver on both T1-weighted and T2-weighted images. Central tumor scars are a frequent but nonspecific feature of both benign and malignant primary liver tumors.