Introduction: Extradural spinal cyst is a rare cause of compression myelopathy. It is usually solitary and its typical location is posterior to the spinal cord. We present a case of multiple spinal arachnoid cysts causing diffuse myelomalacia secondary to a significant compression of the spinal cord with no symptom relief after surgical decompression.
Case report: A 35-year-old female patient presented to our hospital complaining of progressive weakness and numbness of both lower extremities for the last 2 months, being more prominent on the right side. Her history was significant for back pain that started after a vaginal delivery 1 year ago. Spinal MRI revealed multiple extradural arachnoid cysts and diffuse myelomalacia. A T4-T6 level laminectomy was performed. The cyst was nearly totally resected. There was partial symptomatic relief after surgery, but 5 months later her symptoms worsened. MRI revealed nodular syringomyelia and atrophy of the thoracic spinal cord.
Conclusions: Extradural spinal arachnoid cyst is to be considered in the differential diagnosis of spinal cord compression. Vaginal delivery may accelerate the process and symptoms by a sudden increase in the cyst size. In cases of myelomalacia secondary to cyst pressure postoperative results are quite poor.