A case of synchronous multiple cancers involving mandibular osteosarcoma and breast cancer.

A rare case of synchronous multiple cancers involving mandibular osteosarcoma and breast cancer is reported. A 49-year-old woman was referred to our department because of a swelling at the left mandibular angle. Extended radical mastectomy had been performed 6 months previously, and the histopathological diagnosis was papillotubular carcinoma. One month after the mastectomy, the patient experienced discomfort of the left mandibular angle and hypalgesia of the left side of the lower lip. Intraoral examination revealed a hard mass, measuling 6×4 cm and covered normal mucosa, in the left lower molar region. Occlusal radiography showed a sun-ray-like appearance at the focus. Bone scintigraphic scans showed an area of increased intake of radiolabeled technetium in the left side of the mandible. Preoperative chemotherapy with a high dose of methotrexate had been given in accordance with Rosen's T-12 protocol, but the tumor grew rapidly. Radical resection of the tumor was performed. Postoperatively, she was given chemotherapy with CDDP and ADM. There have been no clinical or radiological signs of recurrence or distant metastasis as of 9 years after operation.