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.

皮下脂膜炎样 T 细胞淋巴瘤 (SPTCL) 是一种罕见的原发性皮肤淋巴瘤，由 CD8 ⁺主要位于皮下组织的细胞毒性 T 细胞。由于 SPTCL 的稀有性，目前没有标准的治疗方法可用于 SPTCL。化疗、放疗、免疫抑制剂和造血干细胞移植（HSCT）已被频繁使用，但这些治疗方法的效果仍存在争议。在本报告中，我们介绍了一名 47 岁女性的罕见 SPTCL 病例，其初始症状不典型。患者在确诊后开始接受依托泊苷、长春新碱、环磷酰胺、多柔比星和强的松 (EPOCH) 化疗。经过两个周期的化疗，她的临床症状没有明显改善。随后，组蛋白去乙酰化酶 (HDAC) 抑制剂西达本胺从第三个周期开始加入化疗。经过四个周期的化疗联合西达本胺后，她逐渐康复并达到完全缓解（CR），随后是西达本胺单药维持治疗。治疗后 1 年多，她仍处于 CR。我们的案例首次说明，西达本胺可以成为诱导罕见 SPTCL 长期缓解的有效药物。