Chronic Hypertrophic Ganglioneuritis Mimicking Spinal Nerve Neoplasia: Clinical, Imaging, Pathologic Findings, and Outcome after Surgical Treatment

Objective To report the clinical, imaging, pathologic findings, surgical planning, and long-term outcome after surgery in a dog with neurologic deficits because of a hypertrophic ganglioneuritis that compressed the spinal cord. Study Design Clinical report. Animal An 8-year-old male intact Yorkshire terrier. Methods The dog had ambulatory tetraparesis and neurologic examination was consistent with a C1-C5 myelopathy. Magnetic resonance imaging (MRI) revealed enlargement of the left C2 spinal nerve causing compression of the spinal cord. The main differential diagnosis was spinal nerve neoplasia with compression and possibly spinal cord invasion. On ultrasonography, there was enlargement of the spinal nerve and fine needle aspiration did not show evidence of neoplasia. Fascicular biopsy of the spinal nerve was consistent with enlargement because of chronic inflammation (hypertrophic neuritis). Results Hemilaminectomy followed by durotomy and rhizotomy allowed resection of an intradural-extramedullary mass that was the enlarged left C2 spinal nerve. Histopathology was consistent with a hypertrophic ganglioneuritis. Thirteen months later the dog remained free of clinical signs. Conclusion Hypertrophic neuritis affecting the spinal nerves may be misdiagnosed as spinal nerve neoplasia that in dogs is usually malignant with a poor prognosis. Focal spinal nerve lesions with compression of the spinal cord evident on MRI may be inflammatory and are not necessarily a neoplastic condition.