Abstract： Objective To make diagnosis of patient with topiramate-induced hypersensitivity presenting with generalized lesions that mimicked mycosis fungoides clinically and histologically.Methods Drug-specific T cell activation testing,ELIspot assay,and HLA-B*1502 assay were used to identify the disease.Results The patient was initially treated with carbamazepine for 3 weeks,and withdrawal of carbamazepine led to regression of the lesions;however,substitution of topiramate resulted in the reappearance and progressive worsening of infiltrated erythematous plaques several weeks later.Topiramate was subsequently stopped,and the lesions had resolved without relapse during 1-year followup.Immunochemical analysis of the lesion showed that most of the atypical lymphocytes were CD3,CD5,CD4,and Ki-67 (40％-50％) positive but CD8,CD30,CD56,TIA-1,and GrB negative.Drugspecific T lymphocyte activation testing and an enzyme-linked immunospot assay were conducted to quantify drug-reactive T cells and cytokine-releasing cells in peripheral blood mononuclear cell specimens to substantiate the diagnosis of drug eruptions.Conclusion To our knowledge,our report presents the first case of topiramate-induced mycosis fungoides-like lesions based on the clinical and histological evidences.