Thoracic diastematomyelia with concurrent intradural epidermoid spinal cord tumor and cervical syrinx in an adult. Case report.

Diastematomyelia is a rare entity in which some portion of the spinal cord is split into two by a midline septum. Most cases occur in childhood, but some develop in adulthood. A variety of concurrent spinal anomalies may be found in patients with diastematomyelia. The authors describe a 38-year-old right-handed woman who presented with a 7-month history of lower-extremity pain and weakness on the right side. She denied recent trauma or illness. Sensorimotor deficits, hyperreflexia, and a positive Babinski reflex in the right lower extremity were demonstrated on examination. Neuroimaging revealed diastematomyelia extending from T-1 to T-3, an expanded right hemicord from T-2 to T-4, and a C6-7 syrinx. The patient underwent T1-3 total laminectomies, resection of the septum, untethering of the cord, and excision of the hemicord lesion. The hemicord mass was determined to be an intramedullary epidermoid cyst; on microscopic evaluation the diastematomyelia cleft was shown to contain fibroadipose connective tissue with nerve twigs and ganglion cells. Postoperatively, the right lower-extremity pain, weakness, and sensory deficits improved. Diastematomyelia can present after a long, relatively asymptomatic period and should be kept in the differential diagnosis for radiculopathy, myelopathy, tethered cord syndrome, or cauda equina syndrome. Numerous spinal lesions can be found in conjunction with diastematomyelia. To the authors' knowledge, this is the first case in which a thoracic epidermoid cyst and cervical syrinx occurred concurrently with an upper thoracic diastematomyelia. Thorough neuraxis radiographic evaluation and surgical treatment are usually indicated.