Ultrasonographic evaluation of the muscularis propria in cats with diffuse small intestinal lymphoma or inflammatory bowel disease.

ABSTRACT

BACKGROUND: An ultrasonographic pattern of thickened muscularis propria in the small intestine and lymphadenopathy have been associated with gastrointestinal lymphoma and inflammatory bowel disease (IBD) in cats. OBJECTIVES: To investigate the association of these imaging biomarkers with IBD and lymphoma in cats. ANIMALS One hundred and forty-two cats with a histologic diagnosis of normal small intestine (SI) (n = 56), lymphoma (n = 62), or IBD (n = 24). METHODS: Retrospective case review. Pathology records from 1998-2006 were searched for cats with a diagnosis of normal, IBD, or lymphoma, an ultrasonographic examination < 28 days before surgery, and without ultrasonographic evidence of a mass. Multinomial regression analysis was used to determine the association of imaging biomarkers with disease status. RESULTS: Cats with thickening of the muscularis propria detected by ultrasonographic examination were more likely to have lymphoma compared with normal SI cats (odds ratio [OR] = 4.0, 95% confidence interval [95% CI] 1.2-13.1, P = .021) and those with IBD (OR = 18.8, 95% CI 2.2-162.7, P = .008). Histologic samples of cats with muscularis propria thickening were more likely to have disease infiltrates in both the mucosal and submucosal layers (OR = 8.1, 95% CI 1.7-38.4, P = .008) than cats with normal SI. Cats with ultrasonographic evidence of lymphadenopathy were more likely to have a diagnosis of lymphoma (OR = 44.9, 95% CI 5.1-393.0, P = .001) or IBD (OR = 10.8, 95% CI 1.1-106.3, P = .041) than normal SI. Fifty-six of 62 cats had confirmed or presumptive diagnosis of diffuse T-cell lymphoma. CONCLUSIONS AND CLINICAL RELEVANCE Older cats with muscularis layer thickening are more likely to have T-cell lymphoma than IBD. The ultrasonographic pattern is associated with histologic infiltrates in the mucosal and submucosal layers of small intestine. Lymphadenopathy is associated with lymphoma or IBD.