Schwannoma of the Rectosigmoid Colon

Schwannoma is a rare tumor in the colon which originates from the peripheral nerve plexus. Most of the cases have been asymptomatic but occasionally present as an obstructive mass. Abdominal investigations are effective in some cases, but usually, they are not informative. A significant number of cases have been detected after their operation by histopathology examination. Immune and histochemical staining shows the spindle cells that have been positive for S-100 and vimentin, but negative for CD34 and smooth muscle actin. If the diagnosis of Schowannoma is confirmed preoperatively, segmental resection is recommended. In this case report, we presented a 58-year-old woman with pelvic mass and normal colonoscopy that mimic extramural large uterine myoma with extraluminal pressure effect on the rectosigmoid.