Patterns of liver infiltration in lymphoproliferative disease

Aims: Liver involvement is a common finding in patients suffering from lymphoproliferative disease, and histopathological patterns of infiltration vary according to lymphoma subtype. Data correlating the form of liver involvement with distinct lymphoma subtypes is, however, scarce. The aim was to review 89 liver biopsies diagnosed with lymphoma infiltration and evaluate the infiltration patterns. Methods and results: In equivocal cases, additional immunohistochemical and molecular pathology analyses were performed to differentiate between neoplastic and reactive cell infiltrates and to classify the lymphoma subtypes. Diffuse large B-cell lymphoma (DLBCL), chronic lymphocytic leukaemia (CLL), Hodgkin's lymphoma (HL) and Burkitt lymphoma (BL) were the most prevalent subtypes in our series, which included 14 different lymphoma entities in total. Whereas DLBCL and BL predominantly demonstrated tumour nodules deranging the normal hepatic architecture, CLL and HL mostly showed infiltration of the portal fields. Interestingly, distinct lymphoma entities, particularly marginal zone B-cell lymphomas (MZL) and HL, commonly revealed lympho-epithelial lesions of bile ducts, which were observed in 10% of all investigated cases. Four cases, initially interpreted as T-cell lymphomas, proved to be reactive T-cell lesions. Conclusions: Distinct lymphoma subtypes show characteristic patterns of liver infiltration. Additional molecular analyses can support diagnosis by verification of clonality or detection of characteristic genetic aberrations.