Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare primary cutaneous lymphoma composed of CD8+ cytotoxic T-cell that is primarily localized in the subcutaneous tissue. No standard treatments are currently available for SPTCL due to its rarity. Chemotherapy, radiotherapy, immunosuppressive agents, and hematopoietic stem cell transplantation (HSCT) have been used frequently, however, the effects of these treatment approaches remain controversial. In this report, we present an unusual case of SPTCL in a 47-year-old woman whose initial symptoms were atypical. The patient was started on etoposide, vincristine, cyclophosphamide, doxorubicin, and prednisone (EPOCH) chemotherapy once diagnosed. After two cycles of chemotherapy, her clinical symptoms were not significantly improved. Subsequently, histone deacetylase (HDAC) inhibitor chidamide was added to the chemotherapy from the third cycle. She recovered gradually and achieved complete remission (CR) after four cycles of chemotherapy combined with chidamide, followed by chidamide monotherapy for maintenance. More than 1 year after the therapy, she remained in CR. Our case illustrates, for the first time, chidamide can be an effective agent to induce long-term remission for rare SPTCL.