Patient: Male, 24 Final Diagnosis: Subcutaneous panniculitis-like T-cell lymphoma Symptoms: Fever . skin nodules Medication: - Clinical Procedure: Skin biopsy . PET-CT Specialty: Hematology Objective: Rare disease Background: Subcutaneous panniculitis-like T cell lymphoma is a very uncommon subtype of cutaneous T cell lymphoma. The manifestations of this rare disease are atypical at onset, and may mimic some rheumatic or dermatologic diseases, which causes the delay of diagnosis and treatment. Case Report: We report a 24-year-old man suffering from intermittent fever and skin nodules on the left anterior chest wall, who was initially misdiagnosed with nodular panniculitis and finally diagnosed with subcutaneous panniculitis-like T cell lymphoma through repeat examination of biopsy of the skin nodule. Positron emission tomography revealed extracutaneous adipose tissue involvement. Subsequently, hemophagocytic syndrome occurred while under a conventional dose of glucocorticoid, but remission was induced by treatment with cyclosporine A and high doses of dexamethasone. Conclusions: In order to avoid the delay diagnosis and inappropriate treatment of subcutaneous panniculitis-like T cell lymphoma, in addition to a thorough physical examination, PET-CT and disease-specific pathologic, immunophenotypic, and T cell receptor tests of the skin biopsy should be performed. Extracutaneous involvement, especially hemophagocytic syndrome, indicated worse prognosis. Even so, cyclosporine A plus high-dose corticosteroid could be an option of treatment.