Hepatocellular carcinoma with extensive peliotic change.

Peliosis hepatis is a rare lesion histologically characterized by multiple cavities representing dilated sinusoids filled with blood in the liver. Although it has been observed in the liver parenchyma in association with several diseases and medications, there are few reports of nodules of hepatocellular carcinoma (HCC) showing extensive peliotic change. We describe a case of HCC showing extensive peliotic change in the cancer nodule. A 73-year-old man with a liver tumor was referred to our hospital for further investigation. Abdominal ultrasonography revealed an 8-cm hyperechoic lesion with a halo and mosaic pattern in segment 8 (S8) of the liver. Dynamic magnetic resonance imaging of the liver showed early irregular enhancement of the peripheral part of the lesion, and the effect persisted into the late phase, spreading into the central part of the nodule. Hepatic arteriography showed the "cotton-wool" sign, usually observed in cavernous hemangiomas. Fine-needle aspiration biopsy revealed the diagnosis of HCC. Anterior sectionectomy of the liver was conducted. Histological examination of the resected specimen showed that the tumor was a well-differentiated HCC with extensive dilated sinusoid-like structures in the main portion of the nodule, suggestive of peliotic change.