肺癌術後のFDG-PET/CTにおいて頸部リンパ節転移と考えられたが神経鞘腫であった1例

A case of schwannoma thought to be cervical lymph node metastasis on FDG-PET/CT after surgery for lung cancer

神経鞘腫はSchwann細胞由来の腫瘍であり，頸部や四肢に好発することが知られている。肺癌術後のFDG-PET/CTで頸部に集積を認め，肺癌の頸部リンパ節転移の可能性を否定できなかった良性神経鞘腫の1例を経験したので文献的考察を加えて報告する。

A woman in her 80s underwent surgery for pulmonary adenocarcinoma in the upper lobe of the right lung. A CT scan 14 months postoperatively showed a tendency of enlargement of the nodule in her right neck, so FDG-PET/CT was performed, revealing FDG accumulation at the lesion. Cervical lymph node metastasis was suspected. The patient underwent diagnostic biopsy, which showed S-100-positive spindle cells and a diagnosis of benign schwannoma was made. Schwannomas, even benign, may enlarge and result in high accumulation of FDG, so caution is required in distinguishing them from lung cancer recurrence or metastasis.