<unk>  is a disease with an<unk> , systemic proliferation of natural killer cells (NK cells) and a rapidly declining clinical course. There is no classification system for<unk> . The pathogenesis of<unk>  is characterized by the proliferation of natural killer cells.<unk>  is very uncommon, and is most commonly seen among middle aged adults.  The most common risk factors in the development of<unk>  is the Epstein-Barr virus (EBV) infection. The majority of patients with<unk>  are symptomatic at diagnosis. Early clinical features include fatigue, night sweats, and fever. Physical examination among patients with<unk>  may be remarkable for hepatosplenomegaly.<unk>  may also be diagnosed using bone marrow biopsy, findings of which can include extensive marrow replacement by<unk>  cells and reactive histiocytes displaying hemophagocytosis. The mainstay of therapy for<unk>  is anthracycline-containing chemotherapy.
Aggressive NK-cell leukemia
Blastic NK cell lymphoma
T-cell prolymphocytic leukemia electrocardiogram
Peripheral T cell lymphoma
Adult T-cell leukemia
Angioimmunoblastic T-cell lymphoma
B-cell prolymphocytic leukemia
T-cell prolymphocytic leukemia