Subcutaneous Panniculitis-like T Cell Lymphoma Diagnosed with a Slowly Progressive Course: A Case Report.

Panniculitis is an inflammation that occurs in subcutaneous adipose tissue. Panniculitis includes physical panniculitis (e.g., traumatic) and infectious panniculitis (e.g., bacterial, fungal, subcutaneous panniculitis-like T cell lymphoma [SPCTL], etc.). Accurate diagnosis is crucial due to similar clinical presentation of all types of panniculitis. Here, we report a case of SPCTL which was initially diagnosed with traumatic panniculitis. A 15-year-old male patient was admitted to a previous hospital due to a progressively enlarged right flank and inguinal mass after an abdominal bruise. He was initially diagnosed with traumatic panniculitis, but the mass expanded throughout the chest and abdomen accompanied by a fever of over 11 months. Computed tomography (CT) revealed a subcutaneous mass in the anterior chest and abdominal wall. Fludeoxyglucose F18 (FDG) uptake was observed at those lesions using FDG-positron emission tomography (PET). A biopsy of the mass lesion was performed, during which SPCTL was diagnosed based on pathological examination. He was initially treated with prednisolone and cyclosporine A for two weeks. His fever went down, but subcutaneous mass in the chest and abdominal wall persisted. Therefore, he received a cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) regimen. After 6 courses of CHOP, CT revealed no disease evidence. He remained in complete remission at 30 months of therapy.