Primary non-Hodgkin's lymphoma in the dorsolumbar muscles

We report a case of primary soft tissue lymphoma with pulmonary involvement in a 57-year-old man, successfully treated with surgery and chemotherapy. The patient presented with a giant mass (16 × 20 cm) in the left dorsolumbar region. Computed tomography (CT) demonstrated a right-sided pulmonary tumor, in addition to the giant tumor in the left dorsolumbar muscles. On an incisonal biopsy, the left dorsolumbar muscle tumor was suspected to be a sarcoma, and en-bloc resection was therefore performed. During surgery, four left pulmonary tumors that had not been observed on CT were found and surgically resected. The patient was finally diagnosed with soft tissue non-Hodgkin's B cell lymphoma with pulmonary involvement. After postoperative chemotherapy, the right pulmonary nodule disappeared. The patient was well and had no evidence of disease 22 months after surgery. To the best of our knowledge, primary soft tissue lymphoma is extremely rare.