Likely radiation-induced sciatic neuropathy in a dog.

Radiation-induced peripheral neuropathy (RIPN) is a well-known late adverse effect of radiotherapy (RT) in humans, but to date, is not reported in companion animals. An 11-year-old spayed female beagle was presented for evaluation regarding a progressive left sciatic neuropathy. The dog had received stereotactic RT (20 Gy) following excision of a grade 2 soft tissue sarcoma over the proximo-caudal aspect of the left thigh approximately 19 months prior to the onset of signs. Computed tomography and magnetic resonance imaging of the left sciatic nerve was consistent with RIPN, and histopathology of the sciatic nerve supported severe nerve fiber loss. No improvement was observed with an anti-inflammatory course of corticosteroids, and the affected limb was subsequently amputated.