A Case of Sigmoid Mesenteric Schwannoma Resected Laparoscopically

Abstract

A 25-year-old woman who had an intrauterine contraceptive device implanted for dysmenorrhea was found to have a pelvic mass by a follow-up transvaginal ultrasonography. Pelvic MRI revealed a suspected 8-cm diameter mesenchymal tumor of the gastrointestinal origin. She was referred to our department for further examination and treatment. Abdominal contrast-enhanced computed tomography scan revealed a suspected schwannoma or extragastrointestinal stromal tumor of the sigmoid mesenteric origin. A diagnostic surgery was performed and laparoscopic observation showed that the encapsulated tumor was located in the sigmoid mesocolon, with no evidence of invasion into other organs or peritoneal metastasis, and the inferior mesenteric artery after the left colonic artery branch was involved in the tumor. We performed laparoscopic sigmoidectomy including the tumor, not to damage the tumor capsule. There were no postoperative complications. Immunohistochemical staining was strongly positive for S-100 protein, and negative for c-kit, CD34, and α-smooth muscle actin. The diagnosis of mesenteric schwannoma was confirmed. We report this case, because sigmoid mesenteric schwannoma is rare, and few cases have been treated laparoscopically.