In order to search for molecular markers that may predict the therapeutic effect of Chidamide and promote precise treatment and overall prognosis of SPTCL, we report here a refractory/recurrent SPTCL patient with AT-rich interaction domain 1A (ARID1A) mutation who achieved continuous remission after the addition of Chidamide on the basis of CHOP (cyclophosphamide, doxorubicin, vindesine, and prednisone) plus autologous hematopoietic stem cell transplantation (auto-HSCT). Here, ARID1A is linked to subcutaneous panniculitis-like T-cell lymphoma.