Cutaneous T-cell lymphoma (CTCL) is a group of extranodal non-Hodgkin’s lymphomas originating in the skin and consists of a group of diseases with different clinical manifestations, histologic features, and prognosis. Cutaneous T-cell lymphomas account for approximately 80% of all primary cutaneous lymphomas, with mycosis fungoides being the most common type accounting for approximately 70% of cutaneous T-cell lymphomas. Cutaneous T-cell lymphoma, being an extremely difficult disease to cure, requires a chronic disease treatment regimen that includes biological and cytokine drugs, photochemotherapy, and monoclonal antibody drugs directed at new molecular targets. Classification of cutaneous T-cell lymphoma: In 2005, the World Health Organization (WHO) classification of malignant lymphomas and the European Organization for Research and Treatment of Cancer (EORTC) classification of cutaneous lymphomas were combined, and a new classification system (WHO- EORTC) was proposed at the meeting, with the most significant change being that Sezary syndrome was previously often classified as a variant of mycosis fungoides, but The WHO- EORTC classification system treats the two diseases as separate categories with their own clinical features. Pathogenesis: The pathogenesis of cutaneous T-cell lymphoma is not yet clear. The viral etiology of mycosis fungoides has been proposed by several groups who have identified short sequences of human T-cell lymphoma virus (HTLV)-1 in mycosis fungoides tissue specimens. Other investigators have suggested that the pathogenesis of mycosis fungoides is associated with cytomegalovirus (CMV) and EBV, but there is still a lack of sufficient evidence. Clinical manifestations of mycosis fungoides and Sezary syndrome: Mycosis fungoides lesions are diverse, with initial lesions of erythematous, patchy, scaly plaques that may be associated with pruritus, lesions often confined to non-light areas of the trunk, and skin color changes (skin atrophy with capillary dilation) or associated alopecia. As the lesions progress, they may become infiltrative plaques that are more extensive and can occur in light areas such as the face, and further become tumor nodules or ulcers. Patients usually experience a prolonged period of lesions, ranging from months to years, and Sézary’s syndrome, which usually has a generalized erythrodermic appearance with severe atrophy or mossy skin changes, more pronounced pruritus and desquamation, plaques or tumor nodules that may coexist, usually with enlarged lymph nodes and greater than 5% cerebral gyrus-like malignant T cells in the peripheral blood. When the disease progresses further it can cause hair loss, nail atrophy, and damage to the eyes. Advances in treatment: Because mycosis fungoides and Sezary’s syndrome are difficult to cure, the goal of treatment is to control the progression of the disease while minimizing the toxic side effects of the drugs. Many topical therapeutic agents (nitrogen mustard, steroids, bexarotene) as well as UV-based therapies provide rapid relief of plaques and plaques in the disease, and systemic therapy is indicated for patients who are difficult to control by local treatment or for patients with disseminated plaques and tumorigenic forms. In some patients with progressive disease or where single therapy has failed, a combination of phototherapy, steroid hormones, and biologic agents has been shown to be more effective for patients. IFN-α has become a first-line therapeutic agent for the treatment of cutaneous T-cell lymphoma. Medium-wave ultraviolet light (UVB) has shown good results in early plaque and plaque stage mycosis fungoides. Histone deacetylase inhibitors, vorinostat and peptidoglutethimide have been approved by the U.S. Food and Drug Safety Administration (FDA) for the treatment of cutaneous T-cell lymphoma.