胸腺腫を伴うMorvan症候群の1例

A case of Morvan syndrome associated with thymoma

Morvan症候群は，電位依存性カリウムチャネル（voltage-gated potassium channel：VGKC）に対する自己抗体（抗VGKC複合体抗体）による末梢神経症状，多彩な自律神経症状，辺縁系の異常を示唆する中枢神経症状を特徴とするまれな疾患である^1）2）。Morvan症候群は傍腫瘍症候群として胸腺腫に合併することが多い^2）。今回我々は，胸腺腫を伴うMorvan症候群の1例について画像所見を中心に報告する。

A man in his 50s had experienced autonomic symptoms, involuntary movements, and hallucinations. On non-contrast CT, a well-defined oval mass measuring 4 cm in its long axis was identified in the anterior mediastinum. MRI performed one week later showed a mass with cystic degeneration and suggested a reduction in size to 3 cm in the long axis. Based on the clinical presentation and imaging findings, Morvan syndrome associated with thymoma was suspected. A strongly positive anti-voltage-gated potassium channel complex antibody was detected, leading to the diagnosis of Morvan syndrome. Histopathological examination of the mediastinal tumor confirmed type B3 thymoma.