Magnetic resonance imaging features and management of recurrent spinal inflammatory pseudotumor with intramedullary extension in a dog.

A 4-year-old intact female mixed-breed dog was admitted with a 2-month history of progressive thoracic and pelvic limb paresis. Neurological examination localized the lesion to the cervical spine. Magnetic resonance imaging (MRI) revealed a well-defined mass of the spinal cord extending from the third to fifth cervical vertebral level. The mass was T2-weighted hypointense, T1-weighted isointense, with homogeneous contrast enhancement. Based on the surgical, histopathological, and microbiologic findings, the lesion was diagnosed as an inflammatory pseudotumor. At 55 days postoperatively, the patient demonstrated marked gait improvement, and MRI confirmed successful mass removal with a small residual intramedullary lesion at the C5 level. Follow-up MRI at day 118 exhibited tumor recurrence, and hypofractionated radiotherapy was administered. One month after treatment, MRI demonstrated lesion size reduction.