斜台部に発生したfibrous dysplasiaの1例

Radiographic Characteristics of Fibrous Dysplasia of the Clivus: A Case Report and Review of the Literature

Ⅰ．はじめに

　Fibrous dysplasiaは骨が部分的に破壊，または硬化性骨形成により障害をうける疾患で^1,10)，主として全身の骨格骨，特に長管骨，肋骨および頭蓋骨に発生する．一方，最近では，CT，MRIの精度の向上と普及により，無症候もしくは軽度の症状であっても，偶発的に斜台部の腫瘍が発見されるようになった．しかし，斜台部 のfibrous dysplasia は過去の報告が少なく^2,10)，十分に認識されていない．今回われわれは，斜台部に発生したfibrous dysplasiaの1例を経験したので，その画像上の特徴を文献的考察を加えて報告する．

　Whereas fibrous dysplasia is a well-known, developmental skeletal disorder with a benign clinical course, fibrous dysplasia of the clivus is extremely rare and has seldom been reported. Differentiating this benign entity from more aggressive diseases involving the clivus is important for the proper management of lesions in this area. We here report a case of fibrous dysplasia of the clivus and discuss its radiographic features.

　The patient was 55-year-old male who had suffered from headache for months. Physical and neurological examinations found no abnormalities. The computed tomographic (CT) scan and magnetic resonance imaging (MRI) showed an abnormal mass lesion in the lower of the third clivus. On CT scan, the mass lesion exhibited a ground-glass appearance. The lesion was detected as hypointense and a mixture of hyperintense and isointense areas on T1-weighted and T2-weighted MRI, respectively. Heterogenous enhancement was noted after infusion of GD-DTPA. The patient underwent a transsphenoidal resection of the mass and the histopathologic diagnosis was fibrous dysplasia.