Poorly differentiated hepatocellular carcinoma accompanied by anti-Hu antibody-positive paraneoplastic peripheral neuropathy.

The anti-Hu antibody is one of the most famous onco-neural antibodies related to paraneoplastic neurological syndrome, and is associated with small cell lung carcinoma in most cases. Here, we report a case of poorly differentiated hepatocellular carcinoma accompanied by paraneoplastic peripheral neuropathy positive for the anti-Hu antibody. Image inspection before operation revealed that no tumors were found in organs other than the liver, including lung, and that the liver tumor had no metastatic lesion. The liver tumor showed histological appearance of poorly differentiated carcinoma with cartilaginous metaplasia and partial blastoid cell appearance. Most tumor cells presented trabecular-like structure lined by sinusoidal vessels. Immunohistochemically, the tumor cells were positive for low molecular weight cytokeratin and vimentin, partially positive for cytokeratin 19 and CD56, but negative for synaptophysin, chromogranin A and alpha-fetoprotein. Based on the trabecular-like morphology and the results of immunohistochemical staining, we concluded that the tumor was diagnosed as poorly differentiated hepatocellular carcinoma. Anti-Hu antibody-positive paraneoplastic peripheral neuropathy accompanied with liver tumor is extremely rare as far as is known. The presented case indicates that poorly differentiated carcinoma has the potential to be the responsible lesion of anti-Hu antibody-positive paraneoplastic neurological syndrome and systemic work-up is important for the management of this neurological disorder.