前頸静脈リンパ節に転移をきたした下歯肉癌の1例

A case of inferior gingival cancer with metastasis to the anterior superficial cervical nodes

はじめに

　口腔癌のリンパ節転移好発部位はレベルⅠ（オトガイ下・顎下リンパ節）〜Ⅲ（中内深頸リンパ節）で，レベルⅥ（前頸部リンパ節）への転移は稀である。今回，前頸静脈リンパ節に転移をきたし，特異な臨床経過をたどった下歯肉癌を経験したので，その病態について文献的考察を加え報告する。

　A 70-year-old woman was diagnosed with right inferior gingival cancer stage cT2N0M0 and underwent marginectomy of the mandible. We observed a positive surgical margin；therefore, we performed mandibular segment resection, right-sided supraomohyoid neck dissection, and reconstruction using a fibular flap. Histopathological examination showed stage pT4apN0 cancer with a negative surgical margin. She developed metastasis to the anterior superficial cervical nodes, 5 months later and underwent excision, followed by radiation therapy（66 Gy）combined with cetuximab administration. Lymph node metastases recurred 6 months later；however, metastatic lesions disappeared following the administration of nivolumab. Metastasis to the anterior superficial cervical nodes is rare, and we suspected tumor immunity in this case.