篩骨洞に発生した骨肉腫の1症例

A case of osteosarcoma arising in the ethmoid sinus

はじめに

　骨肉腫は原発性悪性骨腫瘍のなかで最も発生数が多く，本邦では人口100万人に対して年間約2人の発症頻度とされている。骨肉腫は一般的に膝関節周囲や上腕骨近位部に多く発生し，頭頸部領域に発生することは稀である。骨肉腫のうち頭頸部領域に発生するものは10％に満たないとの報告もある^1）。今回，われわれは篩骨洞に発生した骨肉腫症例を経験したので報告する。

　Osteosarcoma most commonly occurs in the limbs, but rarely arises in the head and neck. We report an extremely rare case of osteosarcoma in the ethmoid sinus. A 68-year-old man had suffered from right-sided nasal obstrucion for 5 months. He was found a pale-reddish mass in his right nasal cavity. CT and MRI revealed a moltilocular cystic lesion with ossification in the right ethmoid sinus extending to the anterior skull base. Endonasal biopsy showed the lesion was suspected to be a spindle cell tumor. The patient underwent resection of the tumor with skull base reconstruction via craniofacial and endoscopic endonasal approaches in cooperation with neurosurgeons. The histopathological diagnosis proved to be osteosarcoma, and he received postoperative radiotherapy of 60 Gy. The clinical course was uneventful, and the patient was currently free from disease for 15 months after surgery.