A long-term surviving patient with hepatocellular carcinoma including lymphocytes infiltration--a clinicopathological study.

In patients with hepatocellular carcinoma, a diffuse lymphocyte infiltration into the tumor has been reported to be a favorable prognostic factor. Nevertheless, the mechanism of the lymphocyte infiltration is still unknown and HLA-DR antigen expression, which is the cause of lymphocyte infiltration, has never to our knowledge been previously reported in such cases. The patient in this case had hepatocellular carcinoma with a diffuse lymphocytes infiltration into the tumor and was able to survive for 6 yrs and 11 months without any cancer recurrence. The tissue was studied using histologic and immunohistologic methods. Microscopically, lymphocytes infiltrate along the trabeculae of cancer cells. Immunohistochemically, such infiltrated lymphocytes are mainly T lymphocytes. No lysozyme positive cells were seen in the tumor. HLA-DR antigen was diffusely and strongly expressed on the endothelial cells in the tumor, however its expression was minimal on the endothelial cells in the non-cancerous parenchyma. T lymphocytes infiltrated selectively towards the HLA-DR antigen of the endothelial cells in the tumor and the inflammatory infiltrate may thus be related to a distinct category of patients with a favorable prognosis.