大胸筋を含む広範囲筋萎縮を呈した頚椎症性筋萎縮症の1例

Diffuse Muscle Atrophy, Including of the Pectoralis Major Muscle, with Cervical Spondylotic Amyotrophy. Case Report

　大胸筋を含む上肢の広範囲な筋萎縮を呈した，非常に稀な頚椎症性筋萎縮症の1例を報告する．症例は37歳の男性で，右側優位な両上肢の筋萎縮と脱力が主訴であった．大胸筋を含む広範囲な筋萎縮を認めたが，感覚障害や下肢症状は認めず，C3/4～C6/7高位で右側優位な脊髄圧迫を示すMRI所見から頚椎症性筋萎縮症と考えられた．神経内科で運動ニューロン病は否定的と診断され，頚椎椎弓形成術を施行した．術後1年経過し症状の増悪は認めず，近位筋優位に筋力回復を認めている．広範囲に及ぶ脊髄圧迫による前角障害が原因と考えられた．

　We report the case of a 37-year-old male who complained of muscle atrophy and weakness in his right arm.　The clinical examination revealed diffuse muscle atrophy in the right arm, and of the pectoralis major muscle, but no sensory or lower limb involvement.　The MR images showed a unilaterally diffusely compressed spinal cord, and cervical spondylotic amyotrophy (CSA) was suspected.　A neurology consultation ruled out motor neuron diseases, including amyotrophic lateral sclerosis.　We ultimately made a diagnosis of CSA and performed laminoplasty.　One year postoperatively muscle recovery had predominantly occurred in the proximal muscles, and there was no evidence of deterioration.　Cases of CSA with diffuse muscle atrophy, including of the pectolaris major muscle, are very rare, and diffuse compression of the spinal cord is the most likely cause.