Relapsed subcutaneous panniculitis-like T cell lymphoma evaluated by FDG PET/CT A clinical case report

Rationale: Subcutaneous panniculitis-like T cell lymphoma (SPTCL) is a rare primary cutaneous T cell lymphomas expressing a/b T cell receptors that preferentially involves subcutis, and few reports have investigated the diagnosis of suspicious relapsed SPTCL using F-18-fluoro-2-deoxy-D-glucose (F-18-FDG) positron emission tomography/computed tomography (PET/CT). Patient concerns: A 15-year-old woman complaining of a growing painless subcutaneous mass on perinaeum recurred 2 months ago, suggestive of suspicious relapsed SPTCL, underwent FDG PET/CT for diagnosis and treatment follow-up. Diagnosis: Based on the feature of FDG PET/CT images which revealed multiple increased FDG-avid subcutaneous adipose tissue lesions on the left upper arm, the left chest and perinaeum, involvement of bilateral inguinal lymph nodes, and the effective chemotherapy, she was diagnosed with relapsed SPTCL. Interventions and Outcomes: Fortunately, the patient's skin lesions subsided gradually after 3 cycles of cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) regimen. Besides, complete remission was observed on interim-FDG PET/CT after 3 cycles of CHOP treatment. Lessons: FDG PET/CT can clarify the diagnosis in suspicious relapsed SPTCL, avoiding performing skin biopsy again.