These tumors are derived from schwann cells. These cells produce myelin, which insulates nerves facilitating neural transmission. These tumors have been associated with neurofibromatosis .
Malignant change is very rare.
This study was undertaken to determine the clinicopathologic profile of such tumors. A total of 20 colorectal schwannomas were identified and analyzed in a review of 600 mesenchymal tumors of the colon and rectum from the files of the Armed Forces Institute of Pathology. The tumors commonly presented as polypoid intraluminal lesions, often with mucosal ulceration. Rectal bleeding, colonic obstruction, and abdominal pain were the most common presenting symptoms. These tumors ranged from 0.5 to 5.5 cm in diameter.