2026 Volume 79 Issue 7 Pages e95-e103
Eight broiler chickens with gastrointestinal tract duplication cysts were investigated. In four cases, the duplication cysts were closely attached to the proventriculi of the chickens, and in the remaining four cases, the duplication cyst was closely attached to the ventriculus, ileum, esophagus or duodenum of the individual chicken. Macroscopically, seven of the eight cysts were closely attached to the dorsal surface of the alimentary tract. Histologically, the height of the villous projection formed by the epithelia lining, the number of gland-like tissues in the lamina propria and the thickness of smooth muscular layer were measured for each cyst. The ventricular duplication cyst had tall villous projections and many gland-like tissues, and the cyst contained eosinophilic substances arranged in striated patterns in the lumen. The ileal duplication cyst had moderately tall villous projections and moderately many gland-like tissues. For both cysts, the smooth muscular layer was moderately developed. The results suggest that the former and latter cysts are lined with mucosae similar to the ventricular and intestinal mucosae, respectively. Both cysts are the first reported in chickens. Although the exact pathogenesis for gastrointestinal tract duplication cysts is unclear, the dorsal location of most cysts in the examined cases might suggest that the split notochord syndrome theory proposed regarding human cases is the most likely.
