Hepatic pseudolymphoma: a clinicopathological study of five cases and review of the literature

Hepatic pseudolymphoma is a rare and controversial condition, the clinicopathological characteristics of which have not been well documented. In this study, we retrospectively examined clinical and pathological features of five patients (two males and three females, 40-81 years old) with hepatic pseudolymphoma. Two patients had multiple lesions (two lesions each). Three patients had histories of chronic liver disorders, including primary biliary cirrhosis, nonalcoholic steatohepatitis, and chronic viral hepatitis B. Tumor sizes ranged from 0.5 to 5.5cm in diameter (average, 2.1 cm). Histologically, hepatic pseudolymphoma consisted of tumorous infiltrates of mature lymphocytes with multiple lymph follicles or clusters of epithelioid histiocytes. Lymphocytes characteristically extended into nearby portal tracts. Ductal structures positive for cytokeratin 7 were entrapped in the peripheral parts of nodules. In situ hybridization of immunoglobulin light chains revealed B lymphocytes and plasma cells to be polyclonal. In addition, clonal rearrangements of immunoglobulin heavy chains could not be shown in any cases using PCR. Two patients were diagnosed by needle biopsy. Interestingly, their nodules spontaneously diminished in size without any treatment. Malignant transformation was not observed in any cases during the follow-up periods. In conclusion, this study revealed that hepatic pseudolymphoma had benign behavior. The diagnosis of hepatic pseudolymphoma can be challenging especially with biopsied specimens, but could be aided by a characteristic growth pattern, in situ hybridization, analyses of gene rearrangements, or a follow-up based on images. Modern Pathology (2010) 23, 244-250; doi: 10.1038/modpathol.2009.165; published online 13 November 2009