Diagnosis and Treatment of a Spinal Intraosseous Keratinized Cyst of L1 in a Dog.

An 8 yr old female spayed golden retriever presented for a 3 wk history of progressive pelvic limb ataxia. MRI revealed a well-circumscribed T2-weighted hyperintense, T1-weighted poorly contrast-enhancing extradural mass to the right of the spinal cord at the level of L1 causing severe spinal cord compression. A right-sided hemilaminectomy was performed to remove the mass, and histopathology revealed an intraosseous keratinized cyst. A complete neurologic recovery was made within 2 wk following the surgery. This case illustrates a rare diagnosis and the first case report describing MRI findings and favorable clinical outcome after surgical management of a spinal intraosseous keratinized cyst.