軽度の神経症状にて発見された片側性裂脳症の2成人例―CT診断の重要性―

Two Adult Cases of Unilateral Schizencephaly Manifesting as Minor Neurological Signs－Importance of Radiographic CT Assessment－

要旨　軽度の神経症状にて発見された片側性裂脳症の2成人例を報告した。症例1は52歳女性で，右顔面と上肢の部分発作にて発症した。CTにて左前頭葉に脳裂を認め，MRIでは裂孔部を灰白質が縁取り，脳室壁まで連続していた。抗けいれん剤投与にて発作はコントロールされた。症例2は58歳女性で，生下時より軽度の右片麻痺を伴っていた。頭痛の精査にてCT施行すると，左傍中心溝部に脳裂を認め，MRIでは肥厚した灰白質が裂孔部を縁取り，多小脳回を合併していた。2例とも知的障害は認めず，片側性のclosed-lip typeであった。画像診断技術の向上により，神経症状の軽い片側性裂脳症の報告例が散見されている。詳細な解剖学的評価にはMRIが有用であるが，傍中心溝部の局所的な脳溝拡大や，脳表から白質に拡がる灰白質densityを注意深く読影することで，裂脳症のCT診断は十分可能と思われる。

We report two adult cases of unilateral schizencephaly manifesting as minor neurological signs. Case 1 was a 52-year-old female with an attack of partial seizure. CT demonstrated a closed cleft in the left frontal lobe. MRI revealed that the cleft was covered with gray matter, and was extending to the ventricular wall. Her epileptic seizure was successfully controlled by medication. Case 2 was a 58-year-old female with a history of mild right hemiparesis from her birth. CT demonstrated a closed cleft in the left peri-Rolandic area. MRI revealed a cortical infolding which extended to the lateral ventricle, and complication with polymicrogyria. Two patients were diagnosed as having normal intelligence, and unilateral schizencephalies with closed-lip. There has appeared to be more reports in the recent literature dealing with unilateral schizencephaly with mildly neurologic dysfunction. It is sufficiently capable of making such a diagnosis for schizencephaly by initial CT evaluation of a detailed radiographic assessment, in which characteristic findings with focal enlargement of cortical sulci or appearance of cortical infolding extending to deep white matter will be detected, though MRI is considered to be useful for a more detailed neuroanatomical evaluation.