眼窩内に原発したmesenchymal chondrosarcomaの1例

A case of mesenchymal chondrosarcoma in the orbit

要約　目的：眼窩腫瘍に対し開頭腫瘍摘出術を行い，mesenchymal chondrosarcoma（間葉型軟骨肉腫）と診断できた症例の報告。

症例：42歳男性。3か月前から左眼視力低下を自覚して近医眼科を受診した。遠視化，脈絡膜皺壁を認め，MRIで左眼窩内腫瘍と診断され当科を紹介された。

所見：視力，眼球運動障害，眼位に異常なく，全身的に異常はなかった。開頭腫瘍摘出術を施行し，眼窩原発の間葉型軟骨肉腫と診断した。化学療法，放射線治療は感受性が低いため行わなかった。腫瘍全摘出後の経過は良好で，術後1.5年で再発・転移を認めていない。

結論：間葉型軟骨肉腫が眼窩に生じることがある。

Abstract　Purpose: To report a case of mesenchymal chondrosarcoma originating in the orbit.

Case: A 42-year-old male was referred to us for tumor in the orbit. He had had decreased vision in the left eye since 2 months before.

Findings: Corrected visual acuity was 1.2 in either eye. He showed normal eye position and ocular motility. Magnetic resonance imaging（MRI）showed a well-demarcated tumor in the left orbit. Transcranial removal showed a mesenchymal chondrosarcoma originating the orbit. No chemotherapy or radiotherapy was performed for low sensitivity of the tumor. There has been no recurrence or metastasis for 20 months until present.

Conclusion: This case illustrates that mesenchymal chondrosarcoma may originate in the orbit.