Concomitant hepatocellular carcinoma and non-Hodgkin's lymphoma in a patient with nodular regenerative hyperplasia.

Hepatocellular carcinoma (HCC) is the most common primary cancer in the liver. Liver invasion of non-Hodgkin's lymphoma (NHL) is also often observed. But simultaneous existence of HCC and NHL in a liver is extremely rare. Such patients reported previously had cirrhotic livers. Herein is reported a patient who simultaneously had HCC and NHL in a liver without cirrhosis, but with nodular regenerative hyperplasia (NRH). NHL was of the diffuse large B-cell type. Lymphoma cells invaded the portal vein, and formed thrombi. These thrombi would contribute to the development of NRH by decreasing portal vein blood flow. HCC was of the well-differentiated type and there was a 2 cm-sized nodule at the lateral segment. There is the possibility that NRH was associated with the HCC because NRH is reported as a premalignant lesion. HCC and NHL were colocalized in the liver without hepatic virus infection or cirrhosis, although common cause(s) of development of these malignancies remain unclear in the present case.