An extranodal, mature T-cell non-Hodgkin lymphoma that originates from cytotoxic T-cells, usually of gamma/delta T-cell type. It is characterized by the presence of medium-size neoplastic lymphocytes infiltrating the hepatic sinusoids. A similar infiltrating pattern is also present in the spleen and bone marrow that are usually involved at the time of the diagnosis. The disease is Monarch Disease Ontology term MONDO_0019474 (hepatosplenic T-cell lymphoma). Also known as: Hepatosplenic gamma/Delta T-cell lymphoma.