Intramedullary neurenteric cyst in the spinal cord of a dog

Abstract 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.