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

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.

Keywords: canine; colonic agenesis; congenital; feline; stenosis.

Figure 1

Colon length thresholds used for inclusion criteria.

Figure 2

Age at presentation according to the group (A: animals with clinical signs lasting since the adoption and B: animals with a progressive or acute onset of clinical signs during adulthood).

Figure 3

(A) Right lateral radiograph and (B) Ventro-dorsal radiograph of the abdomen of case 11, a six months old Scottish cat. The descending colon is shorter than expected and abruptly ends in the mid left abdomen (white arrow heads). No other parts of the colon are identified. R: Right.

Figure 4

(A) Right lateral radiograph and (B) Ventro-dorsal radiograph of the abdomen of case 18, an eight years-old Collie dog. The cecum is malpositioned in the left cranial and dorsal abdomen (white arrow heads), in continuity with the descending colon on the lateral view (black arrows). A focal narrowing of the aboral part of the descending colon is observed before it enters the pelvis (black arrow heads). R: Right.

Figure 5

(A) Right lateral radiograph and (B) Ventro-dorsal radiograph of the abdomen of the same cat as on image 2, during positive retrograde colonography. The descending colon is shorter than expected (white arrow heads), the ileocolic junction is identified as a narrowing of the colonic lumen orally (asterisk). Contrast medium is also visible within the small intestine (black arrows). The cecum is not identified. R: Right.

Figure 6

Abnormal ileocolic junction in a cat (Case 10).

Figure 7

Focal colonic stenosis in a cat (Case 15).

Figure 8

Diagnosis repartition (FIP: Feline Infectious Peritonitis, LGITL: Low Grade Intestinal T-cell Lymphoma, PLE: Protein-Losing-Enteropathy, y-o: years-old, LP: lymphoplasmacytic, y-o: years old).

Figure 9

Colectomy in a cat with partial colonic agenesis: the total length was estimated to 8 cm.