title: Tactoid body features in a Schwann cell hamartoma of colonic mucosa.
abstract: BACKGROUND
  Mesenchymal colorectal polyps are uncommon lesions, particularly those of neurogenic origin. We describe a mucosal Schwann cell hamartoma of the colon with tactoid features, so far reported in peripheral nerve sheath tumours, and address its differential diagnosis and clinical implications.
  
  
  METHODS
  A 72-year-old man underwent screening colonoscopy that presented a 5-mm polyp on distal sigmoid. Histologically, it displayed a lesion in the lamina propria comprising oval structures with tactoid features and bland spindle cells, entrapping adjacent crypts. No ganglion cells were seen. Spindle cells expressed only S-100 protein and vimentin.
  
  
  CONCLUSIONS
  Mucosal Schwann cell hamartoma was recently recognized as distinct from common (submucosal) colorectal Schwannomas and so far not associated to inherited syndromes. Thus, it should be considered in the differential diagnosis of look-alike lesions (eg, ganglioneuroma, neuroma, and neurofibroma) that may occur in the setting of inherited syndromes such as Cowden syndrome, multiple endocrine neoplasia-2B, and type 1 neurofibromatosis.
authors.affiliation: IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal Faculty of Medicine, University of Porto, Porto, Portugal Centro Hospitalar de São João, Porto, Portugal.
authors.forename: Francisco
authors.initials: F
authors.lastname: Ferro de Beça
authors.affiliation: Centro Hospitalar de São João, Porto, Portugal.
authors.forename: Joanne
authors.initials: J
authors.lastname: Lopes
authors.affiliation: Unidade Local de Saúde da Guarda, Guarda, Portugal.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Maçoas
authors.affiliation: IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal Faculty of Medicine, University of Porto, Porto, Portugal Centro Hospitalar de São João, Porto, Portugal.
authors.forename: Fátima
authors.initials: F
authors.lastname: Carneiro
authors.affiliation: IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal Faculty of Medicine, University of Porto, Porto, Portugal Centro Hospitalar de São João, Porto, Portugal jmlopes@ipatimup.pt.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Lopes
mesh_terms: D000368:Aged; D003106:Colon / Q000378:metabolism / Q000473:pathology; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology*; D003111:Colonic Polyps / Q000378:metabolism / Q000473:pathology; D003937:Diagnosis, Differential; D006222:Hamartoma / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology*; D008297:Male; D012583:Schwann Cells / Q000378:metabolism / Q000473:pathology*; D014746:Vimentin / Q000378:metabolism
chemical_list: D014746:Vimentin
keywords: Schwann cell; colon; hamartoma; tactoid body