title: Distinguishing Intestinal Lymphoma From Inflammatory Bowel Disease in Canine Duodenal Endoscopic Biopsy Samples.
abstract: Inflammatory bowel disease (IBD) and intestinal lymphoma are intestinal disorders in dogs, both causing similar chronic digestive signs, although with a different prognosis and different treatment requirements. Differentiation between these 2 conditions is based on histopathologic evaluation of intestinal biopsies. However, an accurate diagnosis is often difficult based on histology alone, especially when only endoscopic biopsies are available to differentiate IBD from enteropathy-associated T-cell lymphoma (EATL) type 2, a small cell lymphoma. The purpose of this study was to evaluate the utility of histopathology; immunohistochemistry (IHC) for CD3, CD20, and Ki-67; and polymerase chain reaction (PCR) for antigen receptor rearrangement (T-cell clonality) in the differential diagnosis of severe IBD vs intestinal lymphoma. Endoscopic biopsies from 32 dogs with severe IBD or intestinal lymphoma were evaluated. The original diagnosis was based on microscopic examination of hematoxylin and eosin (HE)-stained sections alone followed by a second evaluation using morphology in association with IHC for CD3 and CD20 and a third evaluation using PCR for clonality. Our results show that, in contrast to feline intestinal lymphomas, 6 of 8 canine small intestinal lymphomas were EATL type 1 (large cell) lymphomas. EATL type 2 was uncommon. Regardless, in dogs, intraepithelial lymphocytes were not an important diagnostic feature to differentiate IBD from EATL as confirmed by PCR. EATL type 1 had a significantly higher Ki-67 index than did EATL type 2 or IBD cases. Based on the results of this study, a stepwise diagnostic approach using histology as the first step, followed by immunophenotyping and determining the Ki67 index and finally PCR for clonality, improves the accuracy of distinguishing intestinal lymphoma from IBD in dogs.
authors.affiliation: Department of Animal Medicine and Surgery, Veterinary Medical Teaching Hospital, Complutense University of Madrid, Avda. Puerta de Hierro s/n, Madrid, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Carrasco
authors.affiliation: Department of Animal Medicine and Surgery, Veterinary Medical Teaching Hospital, Complutense University of Madrid, Avda. Puerta de Hierro s/n, Madrid, Spain Health Surveillance Centre (VISAVET), Complutense University of Madrid. Avda. Puerta de Hierro s/n, Madrid, Spain arbertos@vet.ucm.es.
authors.forename: A
authors.initials: A
authors.lastname: Rodríguez-Bertos
authors.affiliation: Department of Animal Medicine and Surgery, Veterinary Medical Teaching Hospital, Complutense University of Madrid, Avda. Puerta de Hierro s/n, Madrid, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Rodríguez-Franco
authors.affiliation: Diagnostic Center for Population and Animal Health, Beaumont Road, Lansing, MI, USA.
authors.forename: A G
authors.initials: AG
authors.lastname: Wise
authors.affiliation: Diagnostic Center for Population and Animal Health, Beaumont Road, Lansing, MI, USA.
authors.forename: R
authors.initials: R
authors.lastname: Maes
authors.affiliation: Diagnostic Center for Population and Animal Health, Beaumont Road, Lansing, MI, USA.
authors.forename: T
authors.initials: T
authors.lastname: Mullaney
authors.affiliation: Diagnostic Center for Population and Animal Health, Beaumont Road, Lansing, MI, USA.
authors.forename: M
authors.initials: M
authors.lastname: Kiupel
mesh_terms: D000818:Animals; D018951:Antigens, CD20 / Q000378:metabolism; D001706:Biopsy / Q000662:veterinary; D017252:CD3 Complex / Q000378:metabolism; D003937:Diagnosis, Differential; D004283:Dog Diseases / Q000378:metabolism / Q000473:pathology*; D004285:Dogs; D005260:Female; D007150:Immunohistochemistry / Q000662:veterinary; D016130:Immunophenotyping / Q000662:veterinary; D015212:Inflammatory Bowel Diseases / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D007414:Intestinal Neoplasms / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D007422:Intestines / Q000473:pathology; D019394:Ki-67 Antigen / Q000378:metabolism*; D008223:Lymphoma / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D008297:Male; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D018951:Antigens, CD20; D017252:CD3 Complex; D019394:Ki-67 Antigen
keywords: CD3; Ki-67; PCR for antigen receptor rearrangement; canine; clonality; enteropathy-associated T-cell lymphoma; immunophenotyping; inflammatory bowel disease; intestinal lymphoma