Hepatosplenic T cell lymphoma. A review on 45 cases since the first report describing the disease as a distinct lymphoma entity in 1990

Peripheral T cell lymphomas are a heterogeneous group of post-thymic, mature lymphoid malignancies, accounting for approximately 10-15% of all non-Hodgkin's lymphomas. A rare entity within this group is represented by hepatosplenic gamma delta T cell lymphoma, which is characterized by primary extranodal disease with typical sinusoidal or sinusal infiltration of the liver and the spleen, respectively, by expression of the T cell receptor gamma delta chain, and by a number of other frequent clinicopathological features including aggressive course of disease. In contrast to these common attributes some biologic characteristics such as expression of cytotoxic proteins and cytotoxic activity have been controversial. In this review, clinicopathological, immunophenotypical, molecular biological, cytogenetical and biological findings, and diagnostic and therapeutic difficulties in hepatosplenic gamma delta T cell lymphoma are discussed.