Colon and rectum
Schwannoma is a benign nerve sheath tumour that is typically encapsulated and composed entirely of well-differentiated neoplastic Schwann cells. The vast majority of schwannomas follow a benign clinical course (WHO grade I)
Louis DN, Ohgaki H, Wiestler OD, Cavenee WK (Eds.)
. Multiple schwannomas are associated with neurofibromatosis type II (NF2)
WHO Classification of Tumours of the Central Nervous System.
International Agency for Research on Cancer: Lyon 2007
Schwannoma of the colon and rectum
Schwannomas similar to those in the stomach occur in the colon and rectum, usually in older adults. Presentations include gastrointestinal bleeding and a polypoid, obstructing, intraluminal mass. The histological features of these tumours are similar to those in the stomach, with the typical features including peritumoral lymphoid cuff and microtrabecular architecture. Small mucosal nerve sheath tumours occur in the colon and rectum. The designation “mucosal Schwann cell hamartoma” has also been used for apparently similar lesions. These tumours are clinically indolent and are not associated with neurofibromatosis type 1 (NF1)
Gibson JA, Hornick JL (2009)
Mucosal Schwann cell "hamartoma": clinicopathologic study of 26 neural colorectal polyps distinct from neurofibromas and mucosal neuromas.
Am J Surg Pathol 33: 781-7
Miettinen M, Shekitka KM, Sobin LH (2001)
Schwannomas in the colon and rectum: a clinicopathologic and immunohistochemical study of 20 cases.
Am J Surg Pathol 25: 846-55
Bosman FT, Carneiro F, Hruban RH, Theise ND (Eds.)
WHO Classification of Tumours of the Digestive System.
International Agency for Research on Cancer: Lyon 2010