title: Schwann cell hamartoma: case report.
abstract: BACKGROUND
  Colorectal polyps of mesenchymal origin represent a small percentage of gastrointestinal (GI) lesions. Nevertheless, they are encountered with increasing frequency since the widespread adoption of colonoscopy screening.
  
  
  METHODS
  We report a case of a small colonic polyp that presented as intramucosal diffuse spindle cell proliferation with a benign cytological appearance, strong and diffuse immunoreactivity for S-100 protein, and pure Schwann cell phenotype. Careful morphological, immunohistochemical and clinical evaluation emphasize the differences from other stromal colonic lesions and distinguish it from schwannoma, a circumscribed benign nerve sheath tumor that rarely arises in the GI tract.
  
  
  CONCLUSIONS
  As recently proposed, this lesion was finally described as mucosal Schwann cell hamartoma.
authors.affiliation: Department of Medicine, Surgery and Dentistry, Division of Pathology, A,O, San Paolo and Fondazione IRCCS Cà-Granda Ospedale Maggiore Policlinico, University of Milan Medical School, Milan, Italy.
authors.forename: Elena Guerini
authors.initials: EG
authors.lastname: Rocco
authors.forename: Francesca
authors.initials: F
authors.lastname: Iannuzzi
authors.forename: Alessandra
authors.initials: A
authors.lastname: Dell'Era
authors.forename: Monica
authors.initials: M
authors.lastname: Falleni
authors.forename: Laura
authors.initials: L
authors.lastname: Moneghini
authors.forename: Franca
authors.initials: F
authors.lastname: Di Nuovo
authors.forename: Paola
authors.initials: P
authors.lastname: Braidotti
authors.forename: Gaetano
authors.initials: G
authors.lastname: Bulfamante
authors.forename: Solange
authors.initials: S
authors.lastname: Romagnoli
mesh_terms: D000368:Aged; D003108:Colonic Diseases / Q000473:pathology*; D003111:Colonic Polyps / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006222:Hamartoma / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D012583:Schwann Cells