後腹膜原発神経鞘腫に対する腹腔鏡下切除の1例

A case report of a retroperitoneal schwannoma resected by laparoscopic surgery

◆要旨：患者は34歳，女性で左下腹部の腫瘤を主訴に当院に紹介となった．左下腹部に超鶏卵大の弾性硬の腫瘤を触知し，腹部CTおよびMRIでは境界明瞭な径5cmの多房性の腫瘍を認めた．小腸の血管は腫瘍の腹側を，下腸間膜動静脈は背側を走行し，また腫瘍の位置の変化もみられ腸間膜由来の腫瘍と考えた．囊胞変性を伴うGISTや神経原性腫瘍などを疑い，腹腔鏡下に手術を施行した．腫瘍は左右の総腸骨動脈分岐部上に存在する後腹膜腫瘍で自律神経との移行部を認めた．病理診断は神経鞘腫で悪性所見はみられなかった．術前画像所見で腸間膜腫瘍と考えられた後腹膜原発神経鞘腫に対し腹腔鏡下に切除したので若干の文献的考察を加えて報告する．

　A 34-year-old man with a left lower abdominal mass was admitted to our hospital. The egg-sized, elastic hard mass was palpable in the left side of abdomen. Computed tomography and magnetic resonance imaging revealed a 5 centimeter, well defined multicystic tumor in the left lower abdomen. Because this mass existed below the mesenterium of the small intestine and above the mesenterium of the left colon with mobility, we considered this tumor to be a mesenteric tumor. We performed laparoscopic surgery on the diagnosis of gastrointestinal stromal tumor with cystic degeneration or neurogenic tumor. The tumor existed at the retroperitoneum, and originated from the autonomic nerve fibers. Histopathological diagnosis was retroperitoneal schwannoma without malignancy. Schwannoma derived from retroperitoneum is relatively rare. We reported a retroperitoneal schwannoma, which was difficult to distinguish from a mesenteric tumor preoperatively, resected by laparoscopic surgery with some relevant literatures.