RESUMO
Cutaneous T-cell lymphoma (CTCL) describes a group of lymphoproliferative disorders characterized by localization of neoplastic T lymphocytes to the skin. Mycosis fungoides (MF) represents the most common type of CTCL and accounts for â¼60% of all primary cutaneous lymphomas. Apart from the classic type of MF, many clinical and histopathologic variants have been described. The malignant lymphocytes in MF are usually CD3, CD4 and CD45RO positive and CD8 negative. An unusual immunohistochemical profile of a CD4-negative and CD8-positive mature T-cell phenotype has been reported in a minority of patients; up to 20% of early-stage MF demonstrates a CD8-positive phenotype. There are only a few cases of a double-negative CD4/CD8 MF phenotype reported in the literature. We present the case of a 60-year-old male presenting a double-negative CD4/CD8 MF phenotype.