Hemophagocytic Lymphohistiocytosis: A Practical Review for Liver Pathologists

Hemophagocytic lymphohistiocytosis (HLH) is a rare disease with a high mortality. Liver involvement is common, with most patients demonstrating acute hepatitis. Therefore, liver biopsies are frequently obtained in the setting of suspected HLH. Several studies have described the clinicopathologic manifestations of liver involvement by HLH. The histology is highly variable, as are rates of demonstrated hemophagocytosis. This review summarizes the clinical characteristics of HLH, with particular emphasis on hepatic manifestations thereof. We then describe the histologic patterns that have been commonly and uncommonly reported. Finally, we address difficulties faced by liver pathologists when considering this entity and offer our opinions regarding the worst “pain points.”