Adult T‐Cell Leukemia/Lymphoma and Cutaneous T‐Cell Lymphoma Are They Related?

ABSTRACT: Comparative studies were performed on clinical and laboratory features of four patients with different types of T‐cell lymphoma of the skin; adult T‐cell leukemia/lymphoma (ATLL), Sézary syndrome, mycosis fungoides, and Ki‐1‐positive lymphoma. All neoplastic cells studied showed a helper‐inducer T‐cell phenotype. A Ki‐1‐positive lymphoma is distinct from other types of cutaneous lymphomas because of unique morphologic and phenotypic features. Clonal proliferation of lymphocytes infected by human T‐cell lymphotrophic virus (HTLV)‐l distinguishes ATLL from other T‐cell lymphomas of the skin, especially in the endemic area of ATLL. From the pathogeneic point of view, ATLL should not be included in a group with mycosis fungoides and Sezary syndrome.