Background and Aim: Conus medullaris dermoid cysts are benign lesions, usually observed in the lumbosacral region of the spinal canal. Such lesions are often associated with congenital dermal sinus tracts and spinal dysraphism. 
Case Presentation: We reported a 37-year-old man with progressive paralysis distal part of the left lower limb presented to our clinic. The MRI of the lumbar spine, as a modality of choice, has revealed a well-defined sausage-shaped lesion, a multilobular cyst, and the heterogeneous contrast enhancement of an intra- and extra-medullary lesion in the conus medullaris region. 
Conclusion: Subtotal microsurgical resection was performed on the lesion. The result of histopathological examination confirmed the dermoid cyst, as well. After conducting the subtotal resection, an appropriate clinical result was achieved in the patient.