Objective To analyze the clinical and histopathological features,immunophenotypes,treatment and prognosis of subcutaneous panniculitis-like T cell lymphoma (SPTL).Methods Clinical and experimental data were collected from 9 cases of SPTL,and retrospectively analyzed.Related pathological and immunohistochemical markers were examined by Envision method.Eight patients were followed up.Results Of the 9 patients,8 had multiple subcutaneous nodules and plaques,which mainly involved the lower limbs in 8 patients and the trunk in 6 patients.Seven patients had fever.Three patients were subjected to the whole-body positron emission tomography-computed tomography (PET-CT),and 7 to bone marrow aspiration.No visceral tumors and hemophagocytic syndrome were found.Histopathological examination of skin lesions showed atypical mononuclear cells with large nuclei and deep staining,which mainly infiltrated the subcutaneous adipose tissue and were arranged in a circular pattern.Among 9 patients,infiltration of tumor cells was observed around skin appendages and blood vessels in the dermis in 5 patients.Immunohistochemical examination showed positive staining for βF1,CD3 and CD8 in tumor cells in 9 cases,positive staining for granzyme B and T-cell-restricted intracellular antigen-1 (TIA-1) in 8 cases,and negative staining for CD4,CD20,CD30 and CD56 in all the patients.Five patients received chemotherapy,including a child and a postpartum woman.One child received methylprednisoloue pulse therapy.During the follow-up,8 patients achieved a complete clinical remission after treatment.Conclusion SPTL is derived from α/β T cells,and histopathological and immunohistochemical examinations can be helpful for its diagnosis and differential diagnosis.