脂肪腫を伴った上強膜骨性分離腫の1例

A case of epibulbar osseous choristoma with lipoma

要約　目的：上強膜骨性分離腫1例の報告。症例：幼児期から右眼上耳側球結膜下にある腫瘤を主訴として受診した10歳男児。所見：腫瘤は弾力性に富み，表面が平滑な淡黄色であり，磁気共鳴画像検査（MRI）のT1強調画像で耳側眼球壁に高信号領域と，その後方に無信号領域があり，腫瘤の陰影は脂肪抑制像で抑制された。切除された腫瘤は，軟性腫瘤下に線維性被膜で包まれた硬性腫瘤からなり，軟性腫瘤は脂肪腫，硬性腫瘤は上強膜骨性分離腫と診断された。結論：本症例の術前診断にはMRIが有用であった。

Abstract.　Purpose：To report a case of epibulbar osseous choristoma with lipoma. Case：A 10-year-old boy presented with an epibulbar nodule in his right eye since infancy. Findings：The tumor was elastic and had a smooth yellowish surgace. Magnetic resonance imaging（MRI）showed a low-density area posterior to a high-density one in the temporal surface of eyeball on T1-weighted image. The high-density area was suppressed by fat-suppression imaging on T2-weighted image. The excised tumor consisted of soft tumor covering a hard tumor with fibrous capsule. The soft tumor was identified as lipoma and the hard tumor as osseous choristoma. Conclusion：Magnetic resonance imaging was useful in the preoperative diagnosis in the present case.