Primary Cutaneous Acral CD8 T-Cell Lymphoma.

Primary cutaneous acral CD8 T-cell lymphoma is a new provisional entity in the 2016 revision of the World Health Organization classification of lymphoid neoplasms. This is a challenging diagnosis because of its rarity, as well as its morphologic and immunophenotypic overlap with other CD8 cytotoxic lymphoid proliferations. Appropriate classification of this entity is crucial because of its indolent clinical behavior compared with other CD8 T-cell lymphomas. Knowledge of the clinical setting, sites of involvement, and morphologic features can aid in correct diagnosis. Here, we review the clinical and pathologic features of primary cutaneous acral CD8 T-cell lymphoma with an emphasis on the differential diagnosis among other C8 T-cell lymphomas.