Neurenteric cyst with associated butterfly vertebrae in a seven-month-old colt

Spinal neurenteric cyst in a dog

CASE DESCRIPTION An 11-year-old English Cocker Spaniel was evaluated because of chronic progressive ataxia of the hind limbs. CLINICAL FINDINGS The dog had no history of previous illness, and findings of physical examination and laboratory tests were unremarkable. Neurologic examination revealed that the dog was ambulatory with severe ataxia of the hind limbs. Proprioception was decreased in the right and left hind limbs (right affected more than left), and spinal reflexes were bilaterally unremarkable. Moderate signs of pain were detected during palpation of the lumbar portion of the vertebral column. Findings suggested a lesion within the thoracolumbar or lumbar segments of the spinal cord. Magnetic resonance imaging revealed extradural spinal cord compression attributable to an extradural space-occupying lesion originating from or infiltrating the L4 lamina on the right side. TREATMENT AND OUTCOME Hemilaminectomy was performed to remove the extradural lesion. Histologic findings for tissue samples collected during the procedure were consistent with a neurenteric cyst. The late onset and progression of clinical signs of this rare congenital malformation were suspected to have been the result of enlargement of the neurenteric cyst through continuous production of mucus by goblet cells. The dog responded favorably to surgical decompression and was clinically normal 1 year after surgery. It was euthanized 2 years after surgery for an unrelated reason (end-stage heart disease), and no neurologic deficits were evident before that point. CLINICAL RELEVANCE Congenital neurenteric cysts should be considered as a differential diagnosis for neoplastic disease in dogs in which results of diagnostic imaging indicate the presence of an extradural mass affecting vertebral structures.

Spinal cord malformations

Malformations of the spinal cord are one of the most frequent malformations. They should be clearly divided into two completely different families of malformations: open dysraphisms and occult dysraphisms. Open dysraphism mostly consists in myelomeningocele (MMC). Its incidence is 1/1000 live births with a wide variation. Folic acid supplementation has been shown to reduce its risk. In most cases, the diagnosis is done prenatally by serum screening and ultrasound and may lead to termination of pregnancy. In case of decision to continue pregnancy, surgical treatment must be achieved during the first days of life, and in 50 to 90% of cases, a ventricular shunt must be installed. The follow-up of these children must be continued throughout life looking for late complications (Chiari II and syringomyelia, vertebral problems, neuropathic bladder, tethered cord). Occult dysraphisms are a heterogeneous group of malformations. Lipomas (filum and conus) are the most frequent and their treatment remains controversial. Diastematomyelia, neurenteric cysts, dermal sinus, and more complex forms (Currarino syndrome) belong to this group. Most of them can and must be diagnosed prenatally or at birth by careful examination of the lower back for the cutaneous stigmata of the disease to decrease the risk of neurological, urological, or orthopedic permanent handicap.