正中神経に生じた巨指症を伴わないfibrolipomatous hamartomaの1例

Fibrlipomatous Hamartoma of the Median Nerve without Macrodactyly : Case Report

　抄録：巨指症を伴わないfibrolipomatous hamartomaの1例を経験したので報告する．

　症例は35歳，女性．左手関節部掌側に腫瘤を認めた．腫瘤に圧痛はなく，Tinel's sign陽性，母指球筋の萎縮を認めた．MRI T1，T2強調像とも，高信号と低信号の混在した構造を示し，矢状断面像では線状の縞模様像を示した．手根管開放術を行った．手術所見では手首皮線近位から，運動枝・総指神経のレベルまで神経の肥大を認めた．Fascicleの1本を分離採取し，生検を行った．病理所見では緻密な膠原線維の中に小血管・成熟脂肪細胞を認めた．術後，しびれ感は消失し，知覚，母指対立機能ともに改善した．

　We report a case of fibrolipomatous hamartoma of the median nerve without macrodactyly. A 35-year-old woman discovered a painless mass on the volar surface of her left wrist and palm. Clinical examination revealed a positive Tinel sign over the mass and thickening of the thenar muscle. Sensation was diminished in the area innervated by the median nerve. Thickened nerve bundles appeared as hypointense tubular structures on both T1-and T2-weighted MRI images, and they appeared “a conxial-cable-like appearance” on axial images and “a spaghetti-like appearance” on sagital images.

　Carpal tunnel release was performed. Surgical exploration revealed a fusiform enlargement of the median nerve at the level of the common digital nerve, and median nerve decompression was performed. Histopathological examination revealed fat cells and small vessels in the interfascicular connective tissue. After surgery, patient had no complaints, and the clinical findings had improved.