title: Reclassification of small intestinal and cecal smooth muscle tumors in 72 dogs: clinical, histologic, and immunohistochemical evaluation.
abstract: OBJECTIVE
  To reclassify canine small intestinal and cecal leiomyoma (LM) and leiomyosarcoma (LMS) into smooth muscle and gastrointestinal stromal tumors (GIST) using histologic and immunohistochemical (IH) analysis and to report clinical findings and survival data.
  
  
  METHODS
  Retrospective review of cases.
  
  
  METHODS
  Dogs (n=47) with small intestinal (40 LMS; 7 LM) and 25 dogs with cecal tumors (23 LMS; 2 LM).
  
  
  METHODS
  Clinical and survival data were reviewed. Tissue sections were reevaluated for light-microscopic malignancy criteria and examined for expression of SMA, desmin, vimentin, S-100, and CD117 (KIT) by immunohistochemistry.
  
  
  RESULTS
  Reclassification resulted in 2 LM, 9 LMS, 19 GIST, and 17 GIST-like tumors in the small intestine and 23 GIST and 2 GIST-like tumors in the cecum. GIST-like tumors were morphologic and IH identical to GIST but lacked KIT expression. No significant difference in survival was observed for tumor type, location, histologic, or IH characteristics; however, dogs with cecal tumors were significantly older in age, presented more commonly with intestinal perforation and peritonitis, and less commonly with weight loss. Cecal tumors had more histologic malignancy criteria than small intestinal tumors. After excision, 1 and 2 year recurrence-free periods were 80.1% and 67.2% for small intestinal and 83.3% and 61.9% for cecal tumors.
  
  
  CONCLUSIONS
  Prognosis for intestinal tumors with histologic smooth muscle appearance is good after excision and not related to tumor type, location, histologic, or IH characteristics.
  
  
  CONCLUSIONS
  Clinical importance could not be demonstrated for reclassification, but may be for future treatment, of intestinal smooth muscle or stromal tumors.
authors.affiliation: Department of Clinical Sciences of Companion Animals, University of Utrecht, Utrecht, The Netherlands.
authors.forename: Ceriel P H J
authors.initials: CP
authors.lastname: Maas
authors.forename: Gert
authors.initials: G
authors.lastname: ter Haar
authors.forename: Ingrid
authors.initials: I
authors.lastname: van der Gaag
authors.forename: Jolle
authors.initials: J
authors.lastname: Kirpensteijn
mesh_terms: D000818:Animals; D002432:Cecum / Q000473:pathology; D003937:Diagnosis, Differential; D004283:Dog Diseases / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D004285:Dogs; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D007150:Immunohistochemistry / Q000662:veterinary; D007421:Intestine, Small / Q000473:pathology; D007889:Leiomyoma / Q000175:diagnosis / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D007890:Leiomyosarcoma / Q000145:classification / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D008297:Male; D019042:Muscle Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D009364:Neoplasm Recurrence, Local / Q000662:veterinary; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome