Carbon Ion Radiotherapy as an Initial Treatment in an Unresectable Head and Neck Soft Tissue Tumor

Soft tissue tumor is a rare disease in the head and neck regions which is difficult to diagnose and treat. We report on a case of unresectable soft tissue tumor in the head and neck. The patient was a 41-year-old man who noticed some swelling on the right side of his neck which had started three months prior to presenting. A tumor was found in the right neck surrounding his common carotid artery which was judged unresectable because of its location and size. The differentiated diagnosis between a synovial sarcoma and a malignant peripheral nerve sheath tumor (MPNST) was difficult. The patient underwent carbon ion radiotherapy as an initial treatment in the Hyogo Ion Beam Medical Center. There was a partial response from the tumor in his neck tumor, but it metastasized to the lung and bone and the patient died of pulmonary failure nine months after the initial treatment.