Folliculotropic Mycosis Fungoides in 20 Korean Cases: Clinical and Histopathologic Features and Response to Ultraviolet A-1 and/or Photodynamic Therapy

Background Folliculotropic mycosis fungoides (FMF) is a variant of mycosis fungoides (MF) that is characterized clinically by variable types of skin eruptions, including plaques, acneiform lesions, and alopecic patches. Histopathologically, FMF is characterized by folliculotropic infiltrates. Objective This study was conducted to scrutinize the clinical and histopathologic features of FMF in Koreans and the responses to phototherapy. Methods Twenty Koreans diagnosed with MF who had histopathologic evidence of folliculotropism were enrolled. Results Eighteen patients had head-and-neck-region infiltration, while five had solitary lesion. In all patients, the atypical lymphocytic infiltrate had a perifollicular distribution. Twelve patients were treated with ultraviolet A (UVA)-1. Eleven of these 12 patients with early-stage FMF experienced >80% improvement (8: complete remission; 3: partial remission). Four patients, including 2 who relapsed after UVA-1, were treated with photodynamic therapy (PDT), reaching complete remission after PDT. Conclusion As FMF has variable clinical presentations, skin biopsy is required to confirm the diagnosis. And both UVA-1 and methyl aminolevulinate-PDT are clinically effective in treatment of early-stage FMF.