Acute Paralysis Caused by Fibrocartilaginous Embolism in a Pigtail Macaque

An adult female pigtail macaque was evaluated for acute flaccid rear limb paralysis with reduced patellar and anal reflexes. Despite supportive care, antibiotics, and corticosteroids, the monkey showed no improvement and was euthanized 7 days after the onset of clinical signs. Necropsy revealed a soft and swollen spinal cord within the L1 to L3 vertebrae. Microscopic examination of the spinal cord showed severe, diffuse ischemic necrosis, particularly of gray matter. Several small vessels within the spinal nerve root were partially to nearly totally occluded by material resembling fibrocartilage. To the best of our knowledge, this is the first reported case of fibrocartilaginous embolism in a nonhuman primate.