左下腹部痛を契機に診断され腹腔鏡下に切除した腹壁内神経鞘腫の1例

Laparoscopic resection of an intramural abdominal wall schwannoma diagnosed following left lower abdominal pain : A case report

◆要旨：神経鞘腫は末梢神経のSchwann細胞に由来し，多くは良性腫瘍で，腹壁内での発生は稀である．症例は64歳，女性．2年間継続する左下腹部痛を主訴に受診した．CTおよびMRI検査にて腹横筋と内腹斜筋の間に長径3cmの腫瘤を認め，脊髄神経前皮枝由来の神経鞘腫が疑われた．腹腔鏡下腫瘍摘出術の方針とし，体外式超音波で腫瘤の位置を確認後，腹膜前腔を剝離し，腹横筋外側に膨隆する腫瘤を摘出した．病理組織学的検査で，異型の乏しい紡錘形腫瘍細胞と核の柵状配列を認め，S-100陽性より神経鞘腫と診断した．術後，速やかに症状が消失したことから，腹壁への侵襲を最小限に抑えた腹腔鏡下腫瘍摘出術は，有効な治療法であったと考えられた．

　Schwannomas originate from Schwann cells of peripheral nerves. Most are benign, and they rarely develop within the abdominal wall. We report the case of a 64-year-old woman who presented with a 2-year history of left lower abdominal pain. Computed tomography and magnetic resonance imaging revealed a 3-cm mass between the transversus abdominis and internal oblique muscles that was suspected to be a schwannoma originating from the anterior cutaneous branch of a spinal nerve. Laparoscopic tumor excision was planned. The preperitoneal space was established after confirming the location of the lesion using extracorporeal ultrasonography, and the mass bulging from the lateral aspect of the transversus abdominis muscle was removed. Histopathological examination revealed spindle-shaped tumor cells with minimal atypia and nuclear palisading. Immunohistochemistry was positive for S-100 protein, and this confirmed the diagnosis of schwannoma. The patient's symptoms resolved promptly after surgery, suggesting that laparoscopic excision with minimal abdominal wall trauma is effective.