A 5 yr old male neutered Labrador retriever was evaluated for an 8 wk history of a slowly progressive abnormal hind limb gait that did not respond to treatment with nonsteroidal anti-inflammatories.
Initial examination findings were mild pelvic limb ataxia and moderate right pelvic limb lameness. A computed tomography with a myelogram was performed and showed a suspected intramedullary spinal mass. MRI was conducted and supported the computed tomography with myelogram findings of a possible intradural spinal mass at L1.
A left-sided hemilaminectomy followed by a durotomy at L1 was performed and a firm, tan mass was removed.
The histopathologic findings indicated a vascular proliferation most suggestive of a rare proliferative disorder of leptomeningeal blood vessels termed meningioangiomatosis.
Although the dog's signs initially worsened after surgery and he was nonambulatory with marked paraparesis, he regained ambulation within 3-4 wk after the operation. Eighteen months after surgery, he was ambulatory with mild hind limb ataxia with no progression of signs.
This case suggests that surgical resection of lesions of suspected meningioangiomatosis can result in improvement of clinical signs with a good long-term prognosis.