Reactive lymphoid hyperplasia of the liver mimicking hepatocellular carcinoma: incidental finding of two cases.

Reactive lymphoid hyperplasia is a rare disease that forms a mass-like lesion and is characterized by the proliferation of non-neoplastic, polyclonal lymphocytes forming follicles. We recently encountered 2 cases of reactive lymphoid hyperplasia of liver, both of which were asymptomatic and mimicked hepatocellular carcinoma by various imaging modalities. Based on the clinical impression of hepatocellular carcinoma, surgical resections were performed. Microscopic findings revealed that both lesions consisted of an aggregation of lymphocytes consisting of predominantly B-cells, with multiple lymphoid follicles positive for CD10 and negative for bcl-2, consistent with the diagnosis of reactive lymphoid hyperplasia. Polyclonality of both lesions was further confirmed by B cell receptor gene rearrangement study. The incidence of reactive lymphoid hyperplasia in the liver is exceedingly rare, and it is difficult to differentiate such lesions from hepatic malignancies based upon clinical grounds. The clinicopathological findings and literature review of this report may be helpful to improve the clinical decision-making.