Sacro-Caudal Dysgenesis in Two Boxer Dogs: Clinical Presentation, Diagnostic Investigations and Outcome

Two female Boxer dogs from the same litter were presented at 2-months of age for urinary and fecal incontinence. Both dogs had an abnormal tail consisting of a small stump, an atonic anal sphincter and absent perineal reflex and sensation. Electrodiagnostic evaluation showed suspect neurotmesis of pudendal nerves. Radiology and CT scan of the spine displayed similar findings in both dogs: 6 lumbar vertebrae followed by a lumbosacral transitional vertebra, lacking a complete spinous process, and a hypoplastic vertebra carrying two hypoplastic sacral transverse processes as the only remnant of the sacral bone; caudal vertebrae were absent. At MRI, one dog had a dural sac occupying the entire spinal canal and ending in a subfascial fat structure. In the other dog, the dural sac finished in an extracanalar, subfascial, well-defined cystic structure, caudal to the spine and likely communicating with the subarachnoid space, consistent with meningocele. The owners declined surgical treatment. During the 18-months follow-up, the dogs did not show changes in clinical signs except for recurrent cystitis. Sacro-caudal dysgenesis is a malformation of the sacrum, caudal vertebrae and the corresponding spinal cord segments. Similar findings are described in humans in the Currarino syndrome, characterized by a triad of congenital anomalies that are not consistently present together: anorectal malformations, sacrococcygeal osseous defects, and various types of presacral masses (meningocele, enteric cysts or teratomas). To the Authors’ knowledge, this is the first report describing sacro-caudal dysgenesis in dogs. Investigations are underway to identify the genetic basis of this condition.