Myxoid hepatocellular neoplasms: imaging appearance of a unique mucinous tumor variant

To describe the imaging appearance of myxoid hepatocellular neoplasms (MHNs), including adenomas and carcinomas, a recently described pathologically unique tumor variant. Single-institution review of pathologically proven MHNs revealed 4 patients with imaging prior to resection. All available cross-sectional imaging was then retrospectively reviewed in consensus using specified descriptive characteristics previously published for hepatocellular adenoma subtypes. Imaging characteristics on magnetic resonance imaging (MRI), ultrasound (US), and computed tomography (CT) were reviewed. MHNs were predominantly markedly T2 hyperintense with thin internal septations, circumscribed with lobulated margins, and demonstrated heterogeneous enhancement on arterial phase that became more homogenous on delayed phases. The lesions were hypodense on CT with similar enhancement characteristics as on MRI. On US, they were mildly hyperechoic and heterogeneous with posterior acoustic enhancement. MHNs show distinct imaging features that may allow accurate noninvasive diagnosis and differentiation from other hepatic lesions, including cavernous hemangioma, focal nodular hyperplasia, and other variants of hepatocellular adenoma or carcinoma. Differentiation between benign and malignant MHN may not be possible by imaging, possibly necessitating earlier definitive therapy or surgical management.