眼窩骨壁をまたぐ亜鈴型皮様嚢腫の2症例

Two cases of dumb-bell shaped dermoid cyst penetrating the orbital wall through the bony defect

　眼窩内外にまたがる皮様資腫の2例を経験した。1例は29歳男性で，15年前から左眉毛外側に腫瘤を自覚し，腫瘤を圧迫すると眼球が突出した。第2例は52歳女性で，左変視症を主訴とし，網脈絡膜搬襲があった。画像診断で眼窩腫瘤が証明され，眼窩外側骨壁を賃いて亜鈴型に眼窩内外にまたがっていた。側方アプローチによる腫瘍全摘出術を行った。腫瘍は頬骨蝶形骨縫合部の骨欠損孔から眼窩内に連続していた。骨縫合部では骨膜と腫瘍の癒着が強く，剥離中に破嚢した。腫瘍は皮様嚢腫であった。眼窩内外にまたがる亜鈴型皮様嚢腫は側方アプローチのよい適応であるが，成人例では骨欠損部での骨膜との癒着が強固なので，術中の破嚢を避けることが必要である。

We observed two cases of intra- and extraorbital dermoid cyst. One was a 29-year-old man. He had had a tumor lateral to the left eyebrow since 15 years before. Proptosis was induced by pushing the tumor. The other was a 52-year-old woman with metamorphopsia in her left eye. Funduscopy showed retinochoroidal folds. Computed tomography showed orbital tumor in both cases. The tumor penetrated the lateral orbital wall and was dumb-bell shaped. Both cases underwent removal of the tumor through lateral approach. The tumor was continuous through a bony defect in the sphenozygomatic suture. The capsule of the tumor was tightly adherent to the periosteum and ruptured during surgery. The tumor proved to be dermoid cyst. Lateral approach is indicated for dermoid cyst located intra- and extraorbitally. These cases illustrate that due precaution is necessary to avoid rupture of the capsule because of tight adhesion between the capsule and the periosteum in adults.