A rare mature T-cell neoplasm characterized by proliferation of small to medium-sized prolymphocytes with a mature post-thymic T-cell phenotype, involving the peripheral blood, bone marrow, lymph nodes, liver, spleen, and sometimes the skin. T-cell receptor genes are clonally rearranged. Patients typically present with hepatosplenomegaly, generalized lymphadenopathy, high leukocyte count with normal serum immunoglobulins, anemia, and thrombocytopenia. HTLV-1 serology is negative. The disease course is aggressive with generally poor prognosis. [from
ORDO]