眼窩内に発生したMesenchymal Chondrosarcomaの1例

A Case of Mesenchymal Chondrosarcoma in the Orbit

I．はじめに

　眼窩内腫瘍においてmesenchymal chondrosarcomaは稀なものとされており，現在までの諸家の報告は十数例にすぎない．われわれは，本症の1例を経験し手術により全摘しえたので，CT，MRI所見を提示し，若干の文献的考察を加えて報告する．

A rare case of mesenchymal chondrosarcoma of the orbit is presented. MRI findings of this tumor of the orbit are rarely reported.

A 20-year-old female was admitted because of de-creasing It visual acuity. Left exophthalmos and papil-loedema were observed. A CT scan revealed a well de-fined and homogeneous low density mass lesion in the orbit. MRI also demonstrated a low intensity area in T1 weighted image and a slightly enhanced image of GdDTPA. This tumor was completely removed using the frontozygomatic approach. The tumor was encapsu-lated in fibrous tissue. Histologically there were cartila-ginous islands of varied sizes, mixed with a population of highly cellular, small, rounded cells. In some areas the small primitive cell components were growing in a hemangiopericytomatous pattern.