Angioimmunoblastic T-cell lymphoma (AIL-TCL) is a rare subtype of lymphoma, making up only 1% to 2% of nonHodgkin's lymphomas; however, it accounts for a major subset of peripheral T-cell lymphomas. Angioimmunoblastic T-cell lymphoma has clinical and pathologic features that set it apart from other B- and T-cell lymphomas. More recent studies have delineated the immunophenotypic and genetic features of this unusual lymphoma, and have tentatively identified the cell of origin of this neoplasm.