Congenital Partial Colonic Agenesis in Dogs and Cats: Clinical, Biological, Diagnostic Imaging, Endoscopic and Histopathologic Characterization, a Retrospective Study

SIMPLE SUMMARY: Partial colonic agenesis is a rare congenital disorder of the large intestine. However, no study has reported its presentation in dogs and cats yet. The aim of this article is to retrospectively describe the clinical, biological, diagnostic imaging and endoscopic findings of 23 cases of partial colonic agenesis. Although agenesis is a congenital disease, the age of presentation was variable and long asymptomatic periods were common. Abdominal ultrasound was useful and identified the agenesis in 14/17 cats whereas clinical and biological data remained unspecific. Endoscopy allowed precise measurements and diagnosis but also the identification of concurrent lesions. The most frequent associated lesion was colonic stenosis, which might represent a complication of the disease. This study highlighted that partial colonic agenesis could be considered as a possible cause of chronic diarrhea in dogs and cats. Its early diagnosis might prevent further complications such as colonic stenosis. ABSTRACT: Congenital diseases of the large intestine of dogs and cats have scarcely been reported and mostly include fistula, atresia or colonic duplication. Cases of partial colonic agenesis have rarely been described. The purpose of this study was to report a cohort of dogs and cats diagnosed with partial colonic agenesis. The colon was measured during colonoscopy or contrast-radiography and compared to the average length described in the literature. Six dogs and 17 cats were retrospectively included. Depending on the case, partial colonic agenesis could represent an incidental finding or the likeliest cause of clinical signs. Diarrhea was reported in most cases, and no specific clinical or biological abnormality was observed. Median age of presentation was variable and long asymptomatic periods were common. Abdominal ultrasound was useful and identified a short colon in 14/17 cats but only in one dog. Endoscopy was useful to confirm the diagnosis and to identify associated lesions and complications. Among others, colonic stenosis was reported in 8/9 cases that had lifelong clinical signs and the shortest colon length. This anatomical abnormality could promote chronic inflammation that might generate fibrosis and ultimately stenosis.