Ependymal cyst in the conus medullaris.

The immunohistological features and surgical treatment of an intramedullary ependymal cyst in the conus medullaris is presented. An intramedullary ependymal cyst is a rare lesion of dysembryoplastic origin. There have been only seven patients reported with pathologically proven ependymal cysts in the conus medullaris. A 64-year-old woman reported pain and numbness in both thighs and feet. Neither sensory nor motor impairment was present in the lower extremities. MRI revealed a cyst on the right side of the conus medullaris, compressing the spinal cord upward. Clinical signs and symptoms disappeared following surgical resection of the cyst. Histological examination showed that this cyst was lined with a single layer of tall columnar or low cuboidal cells on fibrous connective tissue. The basement membrane was absent in the cyst wall. Reactivity to CAM5.2 and AE1/AE3 anti-keratin antibodies suggested that the cyst was of neuroepithelial origin. No recurrence has been noted 3 years after surgery.