As typically represented by Sézary syndrome, the leukemic form of cutaneous T-cell lymphoma (CTCL) mostly exhibits erythroderma. A patient with CTCL had slowly developing skin tumors as well as chronic leukemia. The tumor cell was CD4⁺ CD7- Th2 cells lacking T-cell receptor/CD3 complex and persistently occupied 27% to 48% of peripheral blood lymphocytes. In skin tumors, only 13% of tumor-infiltrating lymphocytes were malignant cells and substantial numbers of nonmalignant CD4⁺ or CD8⁺ T cells and B cells coinfiltrated. CD8⁺-infiltrating T cells had cytotoxic activity against the malignant T cell. Our case demonstrates the existence of the leukemic form of CTCL presenting with skin manifestation other than erythroderma and parapsoriatic patches. The nonerythrodermic feature and indolent course may be associated with the lack of T-cell receptor/CD3 expression and coinfiltration of a high percentage of nontumor lymphocytes, including tumoricidal CD8⁺ T cells. (J Am Acad Dermatol 2000;43:946-54.)