The sonographic appearance of intestinal mucosal fibrosis in cats

The medical records of 11 cats with full-thickness intestinal biopsies and histopathologic confirmation of segmental mucosal fibrosis were reviewed. All cats received an abdominal ultrasonographic evaluation. The sonographic feature of a small intestinal mucosal hyperechoic band paralleling the submucosa was present in all cats. Other intestinal sonographic findings included wall thickening, and altered wall layering (increased mucosal echogenicity, thickened submucosa, and/or muscularis layer). None of the cats had complete loss of wall stratification. All cats had clinical signs related to the gastrointestinal (GI) tract at the time of presentation. Three of the 11 cats had palpably thickened small intestinal loops, 3/11 abdominal pain, and 2/11 abdominal fluid. Histopathologically, mucosal fibrosis was associated with inflammatory cell infiltrates in all cats. In those cats with histopathologic evidence of mural fibrosis, all cats had a visible hyperechoic band through several intestinal segments. We speculate that the hyperechoic mucosal band represents the zone of mucosal fibrosis. Independently and prospectively, we reviewed the clinical presentation of 35 cats having this visible hyperechoic mucosal band on ultrasound. Twenty-four of these 35 cats had clinical signs related to the digestive system at the time of record. Our study suggests that the hyperechoic mucosal band represents fibrosis, and in presence of concurrent GI signs, further diagnostic tests may be warranted.