Evaluation of the degree and distribution of lymphangiectasia in full-thickness canine small intestinal specimens diagnosed with lymphoplasmacytic enteritis and granulomatous lymphangitis

Abstract

Intestinal lymphangiectasia (IL) is often observed in dogs with chronic small intestinal diseases.Hypoplasia of the lymphatic vessel due to decreased lymphangiogenesis, which has been suggested in human idiopathic IL, may contribute to the pathogenesis of canine IL. This study aimed to evaluate the diameter and number of lymphatic vessels in full-thickness small intestinal specimens of dogs with IL.Immunohistochemical labeling of lymphatic endothelial cell markers was performed on retrospectively retrieved full-thickness small intestinal specimens. Sixteen dogs with histologically confirmed IL were included, of which 10 had lymphoplasmacytic enteritis (LPE), and six had granulomatous lymphangitis (GL). Nine dogs that died from non-gastrointestinal disorders and with little or no abnormalities in the small intestine were used as controls. Lymphatic vessel diameters in dogs with IL were significantly increased in all layers of the small intestine, including the villus lacteal, lamina propria, submucosa, muscularis, and mesentery, compared with controls (all P < 0.01). There was no significant difference in the lymphatic vessel diameters between dogs with LPE and GL (all P > 0.05).There was no significant difference in the number of lymphatic vessels between dogs with IL and the controls in all layers of the small intestine (all P > 0.05). This study demonstrated that IL was observed in all layers of the small intestine, including the submucosa, muscularis, and mesentery, independent of the underlying disease. Factors other than reduced lymphatic vessels would contribute to the pathogenesis of IL in dogs.

Pathophysiology, Diagnosis, and Management of Canine Intestinal Lymphangiectasia: A Comparative Review

“…This study revealed IL in all layers of the small intestine, including the submucosa, muscularis, and mesentery, both in dogs with LPE and LGL. With the exception of one LGL case, dilated lymphatic vessels were observed in both the villus lacteal and deeper layers of the intestine, suggesting endoscopic biopsies should be sufficient to make the diagnosis in most cases [ 65 ]. However, the possibility still remains that IL can go unrecognized in superficial biopsies of the SI, and that it can be limited to areas of the intestine not routinely sampled endoscopically (e.g., jejunum).…”