MR imaging in diffuse-type hepatocellular carcinoma with synchronous portal vein thrombi

Diffuse or continuous multifocal tumors with accompanying portal vein thrombosis yield considerable changes in the magnetic resonance imaging findings of hepatocellular carcinoma. The overlapped imaging findings of these two co-existing pathologies may be confusing. We aimed to evaluate the magnetic resonance imaging findings of widespread hepatocellular carcinoma lesions complicated with portal vein thrombosis.

Twenty-two patients (20 male, 2 female; mean age: 57 years) with portal vein thrombosis and diffuse-type hepatocellular carcinoma who underwent contrast-enhanced hepatic magnetic resonance imaging in our department between August 2001 and November 2008 were evaluated retrospectively. The unenhanced axial T1-weighted, T2-weighted, and post-contrast early- and late-phase images were reviewed in each patient.

On T2-weighted magnetic resonance images, tumors were seen mildly hyperintense in 11 patients and heterogeneously hyperintense in 11 patients. Unenhanced T1-weighted images demonstrated homogeneous hypointensity in 15 patients and heterogeneous hypointensity in 7 patients. Post-contrast early-phase magnetic resonance images showed patchy enhancement in 12 patients, moth-eaten enhancement in 6 patients, strong enhancement in 1 patient, and minimal enhancement in 3 patients. Post-contrast late-phase magnetic resonance images demonstrated heterogeneous washout in all patients. Portal vein thrombosis was present in all patients. The mean diameter of main portal vein thrombi was 27 mm (range: 25-30 mm). Serum alpha-fetoprotein levels were elevated in all patients.

In patients with chronic parenchymal liver disease, when portal vein thrombosis and high serum alpha-fetoprotein values co-exist, careful attention must be paid to the hepatic parenchymal changes, especially on contrast-enhanced images, in order to not overlook diffuse-type hepatocellular carcinoma.