HAVCR2 and subcutaneous panniculitis-like T-cell lymphoma: To address this knowledge gap, we conducted a multicenter retrospective cohort study involving Thai children and adolescents diagnosed with SPTCL to comprehensively examine its clinical characteristics, presence of germline HAVCR2 mutations, occurrence of HLH/HLH-like systemic illnesses, therapeutic regimens, disease outcomes and post-treatment AEs.