Mogamulizumab, a defucosylated humanized IgG1-κ anti-CCR4 monoclonal antibody approved for relapsed/refractory MF/SS, has demonstrated a favorable safety and efficacy profile in multiple case series.<h4>Methods</h4>This retrospective, monocentric observational study analyzed data from 12 patients treated with Mogamulizumab between January 1, 2019, and December 31, 2024. This evidence concerns the gene CCR4 and synovial sarcoma.