A pediatric case of congenital lower thoracic intramedullary epidermoid cyst unrelated to spinal dysraphism combined with retained medullary cord

Abstract

Spinal epidermoid cysts are a rare pathology that accounts for approximately 1% of all spinal cord tumors and can be classified as either congenital or acquired. Most congenital spinal epidermoid cysts are associated with spinal dysraphism. Herein, we report the case of a 39-month-old female patient developed a congenital lower thoracic intramedullary epidermoid cyst unrelated to spinal dysraphism combined with the retained medullary cord. The patient was admitted with progressive paraparesis. Magnetic resonance imaging (MRI) revealed a well-defined intramedullary mass lesion at the T11-12 level exhibiting isointensity on the T1-weighted and hyperintensity on the T2- and diffusion-weighted images. Furthermore, MRI findings demonstrated the retained medullary cord extending to the lower position due to tapering of the conus without visual clue interruption. Surgical removal of the spinal tumor was accomplished via T9-T12 laminectomy. Following a dorsal midline myelotomy, a milky colored fluid seeped out of the tumor cavity, and a dark-reddish wall structure was identified on the surface that was then near-totally removed. The pathology-confirmed diagnosis was an epidermoid cyst with stratified squamous epithelium. The incidence of pediatric intramedullary spinal epidermoid cyst is rare. Postoperatively, the patient’s neurological symptoms completely recovered within a few weeks with no recurrence, and full Karnofsky Performance Status was achieved at the 2-year follow-up. Continuous patient follow-up will be necessary for several years.