umls-concept:C0079774 | skos:definition | MSH: A group of malignant lymphomas thought to derive from peripheral T-lymphocytes in lymph nodes and other nonlymphoid sites. They include a broad spectrum of lymphocyte morphology, but in all instances express T-cell markers admixed with epithelioid histiocytes, plasma cells, and eosinophils. Although markedly similar to large-cell immunoblastic lymphoma (LYMPHOMA, LARGE-CELL, IMMUNOBLASTIC), this group's unique features warrant separate treatment.,NCI: This type of lymphoma is not frequently seen in the western hemisphere. Clinically, with the exception of anaplastic large cell lymphoma, mature T- and NK-cell lymphomas are among the most aggressive of all hematopoietic neoplasms. Representative disease entities include mycosis fungoides, angioimmunoblastic T-cell lymphoma, hepatosplenic T-cell lymphoma, and anaplastic large cell lymphoma.,NCI: Aggressive nodal or extranodal mature (peripheral) T-cell lymphomas that do not belong to the better defined entities of the remainder of mature T-cell lymphomas. T | lld:umls |