This paper describes an osteosarcoma arising from the left ramus which invaded the middle cranial fossa. Although this case was initially evaluated to be inoperable, the authors could completely resect the lesion in cooperation with brain surgeons, after high-dose methotrexate therapy. The patient was a 17-year-old male who presented to our clinic with a complaint of trismus. He had an elastic soft swelling in the left preauricular region, trismus and paresthesia of the mental region.

more »

... showed destruction of the mandible ranging from the left lower second motar region to the left entire ramus and the zygomatic arch. CT scans revealed that the tumor destroyed the middle cranial fossa without invading into the brain. A histological diagnosis of the biopsy specimens indicated the lesion to be an osteosarcoma. After high-dose methotrexate therapy, he underwent radical operation (radical neck dissection, tumor resection, reconstruction of the soft tissue defect with PMMC, reconstruction of the internal jugular vein with a left great saphenous vein graft) . There were no disturbances of the brain after operation. The wound healed uneventfully. The patient has been observed for 30 months without signs of recurrence and metastasis. Although the safety margin at the cranial base was not sufficient, the prognosis was excellent. Therefore, it was concluded that this adjuvant chemotherapy was very effective against osteosarcoma.