Complex Body Wall Closure Defects in Seven Dog Fetuses: An Anatomic and CT Scan Study.

Body stalk anomaly (BSA) is a rare and usually fatal congenital disorder involving severe malformations of the body wall, limbs, spine, and internal organs. This study presents the first documented cases of BSA in seven dogs, offering new insights into how the disorder manifests in animals. The affected fetuses consistently exhibited major anomalies, including large abdominal wall defects, structural spinal abnormalities, and a variety of limb malformations ranging from partial agenesis and meromelia to phocomelia and complete amelia. Structural urogenital anomalies and orofacial clefts were also observed, aligning with similar findings in BSA cases reported in pigs and cats. These findings support the hypothesis of a multifactorial etiology involving early embryonic disruptions, such as abnormal folding of the embryo, rupture of the amniotic membrane, and vascular compromise. The frequent occurrence of abdominal wall defects alongside umbilical cord abnormalities further suggests a shared developmental pathway. This study also highlights the value of veterinary cases in comparative embryology and the need to assess congenital anomalies as part of a broader malformation complex. By expanding the phenotypic spectrum of BSA in domestic animals, this work contributes to a deeper understanding of its pathogenesis and emphasizes the importance of further research into the genetic and environmental factors involved. Such efforts could lead to improved classification and diagnosis of complex congenital malformations, as well as facilitate cross-species comparisons.