Radiological “Snake Eyes” Sign Due to Anterior Epidural Spinal Cyst Mimicking Hirayama Disease (P4.132)

Objective: Improve diagnostic accuracy and treatment of motor neuron disease and increase awareness of anterior epidural spinal cysts mimicking Hirayama’s disease. We review the clinical, electrophysiology and radiological findings of these two uncommon disorders. Background: Anterior epidural spinal cysts mimicking motor neuron disease have been rarely reported. Hirayama’s disease causes focal motor neuronal dysfunction, classically manifesting as insidious and progressive muscle wasting of the forearms and hands. “Snake Eyes” sign has been reported in both amyotrophic lateral sclerosis and Hirayama’s disease. Anterior spinal cysts can mimic Hirayama’s and ALS on exam and electrodiagnostic studies. Design/Methods: Case Report with Review of Literature. Results: A 47 year-old man presented with a six year history of progressive muscular atrophy and painless weakness of his upper extremities. Exam was notable for asymmetric lower cervical myotome weakness, atrophy and fasciculations. Electrodiagnostic studies were compatible with a severe motor neuronopathy confined to the upper limbs, preferentially involving the lower cervical myotomes. MRI of the spine revealed disc osteophyte complex at C5/C6 and C6/C7, the “Snake Eyes” sign and a ventral epidural CSF collection, extending from the lower cervical to lumbar regions. A dural defect was noted at T2/T3. MRI did not show posterior venous engorgement with neck flexion. Attempted dural defect repair was offered but declined. Conclusions: This case demonstrates that anterior spinal cyst may manifest as atypical motor neuron disease, such as Hirayama or amyotrophic lateral sclerosis. Also, it enforces the importance of obtaining radiographic images to asses in evaluating the spine when electromyography and physical exam is inconclusive. To our knowledge, “Snake Eyes” sign has not been reported in anterior epidural spinal cyst. In addition, including anterior cervical spinal cyst in the differential diagnosis of progressive upper extremity weakness and atrophy is important, as this may lead to definitive, attenuating, and possibly curative treatment. Disclosure: Dr. hamdallah MD has nothing to disclose. Dr. Li MD has nothing to disclose. Dr. Twydell has received personal compensation for activities with Allergen and UpToDate.