縦隔悪性末梢神経鞘腫瘍の1例

A case of mediastinal malignant peripheral nerve sheath tumor

縦隔悪性末梢神経鞘腫瘍（malignant peripheral nerve sheath tumor：MPNST）は軟部組織悪性腫瘍の約5％を占める^1）。好発部位は四肢・体幹・頸部で，縦隔・胸腔発生はまれとされている^2）。過半数の症例で神経線維腫症1型（neurofibromatosis type 1：NF1）の合併を伴っている^1）。今回我々は，非NF1の患者でX－9年に縦隔神経線維腫の摘出術の既往があり，同部位に発生した縦隔MPNSTを経験した。NF1を伴わないことや再発までの経過が長期であることも含め，文献的考察を加えて報告する。

A woman in her 40s without neurofibromatosis type 1（NF1）presented with mass in the superior mediastinum, who had undergone surgical resection of a mediastinal neurofibroma nine years earlier. CT and MRI demonstrated progressive enlargement of the lesion. CT-guided biopsy suggested malignant peripheral nerve sheath tumor（MPNST）. Surgical resection was performed, and histopathological examination confirmed the diagnosis of MPNST. This case illustrates that malignant transformation or recurrence of neurogenic tumors can occur even in non-NF1 patients after a prolonged latency period. These findings underscore the necessity of long-term radiological surveillance in patients with previously resected mediastinal neurofibromas, irrespective of NF1 status.