Spinal epidermoid cyst associated with limited dorsal myeloschisis

Epidermoid cysts (ECs) are rare benign tumors arising from epidermal cells, associated with congenital abnormalities or acquired through trauma, surgery, or lumbar punctures. They represent <1% of all intraspinal tumors and may be associated with limited dorsal myeloschisis (LDM). A 7-year-old neurologically intact male had a dorsal skin mass since birth located posteriorly in the midline of the inferior thoracic spine. The mass was palpable, painless, mobile, vascularized, and could be transilluminated. Thoracic magnetic resonance imaging showed an extensive intradural extramedullary cystic lesion extending from D6 to D8 that did not enhance with contrast, accompanied by a subcutaneous fluid collection at D8–D9 communicating with the subarachnoid space. The patient underwent gross total resection of the lesion, pathologically confirmed as an EC. The postoperative course was uneventful, with no recurrence 1 year postoperatively. LDM may be associated with ECs. Early diagnosis and surgical resection of these lesions are essential for favorable outcomes.