Subcutaneous panniculitis-like T-cell lymphoma (SPTCL), an uncommon disorder, was diagnosed in a 17-year-old female when she presented with multiple hard subcutaneous masses that developed over 3 years. She was treated on chemotherapy consisting of cyclophosphamide, doxorubicin, vincristine, and prednisone. Pre- and post-treatment positron emission tomography study demonstrated dramatic resolution of the subcutaneous lesions indicating its usefulness in SPTCL staging and treatment response monitoring.