Intramedullary neurenteric cyst in the spinal cord of a dog

A 7-year-old, female, entire American Staffordshire terrier was presented for chronic progressive ambulatory monoparesis of the right pelvic limb. Magnetic resonance imaging of the thoracolumbar spinal cord revealed a well-demarcated, rounded, slightly right-sided intramedullary space-occupying lesion at the level of T11–12. It was homogeneous, markedly T2-hyperintense when compared to the spinal cord, T1-hypointense and without contrast enhancement. Despite treatment with prednisolone (0.6 mg/kg every 24 hours), the dog deteriorated within 2 weeks to being paraplegic on the day of surgery. A hemilaminectomy was performed over T11–12 on the right, and the intramedullary localisation of the lesion was confirmed. A grey-blueish, gelatinous, walled structure was encountered and, after myelotomy, removed piecemeal from the spinal cord with the assistance of suction and lavage. Histopathology revealed a well-demarcated epithelial cyst consistent with a neurenteric cyst. Follow-up 20 months after surgery revealed mild paraparesis and ataxia, with bunny hopping when running.