Clinical mimicry of hepatocellular carcinoma: imaging-pathological correlation

This pictorial essay aims to show the clinical mimicry of hepatocellular carcinoma (HCC) and its diagnostic difficulty, and to create awareness among clinicians and radiologists of potential diagnostic pitfalls. A selected consecutive series of hepatectomies with proven HCC over a three-year period, identifying clinical presentation, blood results and imaging of patients with difficult preoperative diagnosis, was reviewed. The imaging of the focal liver lesions is presented pictorially with pathological correlation. Six patients out of 34 cases of resected HCC were diagnosed to have benign (three liver abscesses) and neoplastic (one Klatskin tumour, one colorectal liver metastasis, one gallbladder cancer) conditions. Compared to the rest in the series, all six patients had normal serum alpha fetoprotein levels. On computed tomography, the mosaic appearance of HCC mimicked locules of liver abscess while HCC with pseudocapsule (rim enhancement) was misdiagnosed as unilocular abscess or metastatic lesion. Arterial enhancement on contrast-enhanced triphasic computed tomography was useful in diagnosis of HCC. In summary, HCC can mimic benign and neoplastic clinical syndromes. The diagnosis of liver abscess can delay subsequent diagnosis of HCC and potentially complicate the treatment plan. Contrast-enhanced triphasic computed tomography or magnetic resonance imaging is useful to resolve difficult diagnosis, especially when the serum alpha fetoprotein level is not raised.