Primary soft tissue sarcoma: stage IV extranodal T-cell non-Hodgkin's lymphoma.

Non-Hodgkin's lymphoma (NHL) presenting as a soft tissue sarcoma is rare, occurring at a rate of 0.11%. Peripheral T-cell lymphomas comprise 4% of all NHLs. We report the case of a 49-year-old Caucasian man who presented with a mass in the medial aspect of the thigh. Ultrasound showed a complex subcutaneous mass. MRI demonstrated a superficial complex skeletal mass affecting the sartorius muscle with other lesions involving the femur and the gluteus maximus. Positron emission tomography-computed tomography (PET-CT) showed diffuse pulmonary metastases with no involvement of nodes, liver, spleen with high suspicion of advanced sarcoma. Core biopsy revealed a T-cell NHL, and staining was positive for anaplastic lymphoma kinase. The patient received six cycles of cyclophosphamide, doxorubicin, vincristine, etoposide and prednisone. Repeat PET-CT showed reduction in the mass, with no fluorodeoxyglucose-avid uptake. Latest MRI showed near-normal intensity. Further PET-CTs determine disease remission or progression.