Diagnosing a rare thoracic intramedullary spinal dermoid cyst using DWI with ADC mapping: Case report

Dermoid cysts are rare lesions generally associated with embryological errors that occur during neural tube closure. Intramedullary lesions are extremely rare, especially within the upper thoracic spinal cord.

We report a case of a 19-year-old male who had an intramedullary thoracic dermoid cyst presenting with progressive ataxia, lower limb weakness, and hyperreflexia. MRI demonstrated a 1.2 × 1.8-cm intramedullary thoracic dermoid cyst causing significant spinal cord compression, which was successfully removed via full resection. The patient had an uncomplicated postoperative course, with improvement in preoperative deficits.

This is a unique case documenting a thoracic spinal cord intramedullary dermoid cyst not associated with trauma or congenital abnormality of the spinal cord.

We highlight the importance of future inclusion of diffusion-weighted magnetic resonance (MR) imaging (DWI) with apparent diffusion coefficient (ADC), an imaging modality that detects differences in cellularity of spinal cord lesions, for earlier diagnosis of dermoid cyst.