Teaching Case

Middle-aged Egyptian man, immigrated to Western Europe some years ago, suffering from persistent epigastric pain, dyspepsia and decreased alimentary intake following Helicobacter pylori eradication therapy for gastritis.
Despite remote history of HBV infection, he currently tested HCV- and HBsAg-negative. Moderately increased (double the upper normal levels) serum transaminases and alkaline-phosphatase.

Initial sonography (Fig.1) showed hypoechoic thrombosis of entire portal vein and main intrahepatic branches without detectable intraparenchymal focal liver abnormalities.
CT (Fig. 2) confirmed extensive, non-hypervascular thrombosis of portal trunk and intrahepatic branches, and detected a limited, ill-defined hypoenhancing region in the 8th segment, without hypervascular liver lesions. Minimal ascites was present.
After serology and urinary antigens revealed Schistosoma mansoni infection, he was treated with praziquantel and low-molecular-weight heparin. The underlying presence of hepatocellular carcinoma was suggested by markedly elevated (29000 mcg/L) serum alpha-fetoprotein.
Shortly thereafter, MRI with liver-specific gadoxetic acid (Fig. 3, 4) contrast medium depicted the true extent of neoplastic involvement as a vast, approximately wedge-shaped and poorly demarcated parenchymal region with subtly increased T2-weighted signal intensity, restricted high b-value diffusion, precontrast T1-hypointensity and contrast washout, lacking arterial hypervascularity and contrast uptake in the delayed hepatocyte-specific acquisition.

Worldwide, schistosomiasis or bilharziasis represents the second commonest parasitic infection after malaria, and affects over 200 million people throughout tropical and subtropical regions of Africa and America, particularly in association with poverty, poor sanitation and contaminated water: in endemic regions, schistosomiasis may give rise to liver fibrosis, hepatosplenomegaly and portal hypertension. Furthermore, considering global migrations, clinicians in industrialized countries should be aware that Schistosoma mansoni remains a major public health problem and represents a unique risk factor which promotes or accelerates hepatocarcinogenesis. In Egypt, HCC currently occurs with doubled incidence compared to the past decade, affecting 4.7-5.9% of patients with chronic liver disease with a striking (over 80%) male proportion, resulting from a combination of viral, parasitic and environmental factors (aflatoxins, occupational exposure to pesticides). Albeit HCV infection coexists in two-thirds of patients, schistosoma-associated HCCs occur at a younger age (mostly between 40 and 59 years, median 57 years) and are commonly large (over 3 cm) or multifocal at presentation compared to their counterparts with HCV alone: in the largest series, over 54% of HCCs were multinodular or infiltrative at diagnosis, with associated portal vein thrombosis in 18% of cases [1-6].
Compared to alpha-fetoprotein which is markedly increased (>200 ng/ml) in 15.6% of patients only, cross-sectional imaging plays a key role in detecting and assessing the extent of HCC in chronic liver disease, which is often challenging when infiltrative-type tumours involve extensive parenchymal regions, particularly when characterised by permeative growth, minimal or patchy arterial enhancement, and perfusion changes from portal thrombosis. Conversely, MRI including high b-value diffusion-weighted imaging is highly valuable to detect and assess the true extent of neoplastic involvement, which appears as confluent regions of precontrast T1-hypointensity, moderately increased, heterogeneous T2 signal, and restricted diffusion with reticular” or “mosaic” washout appearance in the portal and equilibrium phases, and lack of hepatocyte uptake in the delayed acquisitions after liver-specific contrast medium [7-9].
In conclusion, Schistosomiasis-positive patients from the Nile basin and Brazil (particularly if HCV-coinfected) presenting with laboratory signs of liver dysfunction, portal thrombosis or sonographic hepatic heterogeneity warrant thorough imaging search for possible presence of HCC, best performed with MRI [1, 4].