Intramedullary Epidermoid Cyst of the Conus Medullaris: A Case Report and Literature Review

Abstract

Background

Central nervous system tumors are usually located in the brain, and spinal cord tumors account for approximately 20% of central nervous system tumors. Epidermoid cysts constitute <1% of all intraspinal tumors. It consists of squamous epithelial-lined cysts containing keratin, cholesterol, and cellular granules. Epidermoid cysts can be classified as congenital, acquired, extradural, extramedullary, or intramedullary according to etiology and location. The intradural intramedullary type is uncommon.

Case Presentation

An 11-year-old female patient had back pain with radiation to both lower extremities but worsened on the left side for 5 years. On neurological examination, motor strength was 3/5 for hip flexion and knee extension bilaterally and 5/5 for other key muscle groups. Contrast-enhanced lumbosacral magnetic resonance imaging (MRI) revealed T1 hypointense and T2 hyperintense lesions in the L2-L4 intramedullary conus and cauda equina. Laminectomy and near total resection were done, and histopathological examination revealed an epidermoid cyst. On the third postoperative day, the patient was discharged with completely resolved back pain and an improvement in lower extremity motor power. At monthly follow-up visits for a further 6 months, her back pain and weakness completely resolved, and she had no neurologic deficits. A postoperative lumbosacral MRI was done and confirmed near total excision of the tumor.

Conclusion

Intramedullary conus epidermoid cysts are rare but not unknown to neurosurgeons. MRI with diffusion-weighted images (DWI) is an imaging modality of choice. Asymptomatic patients can be conservatively treated. Once the patient has progressive symptoms and signs of compression, surgical excision is recommended. Meticulous electrocauterization may help decrease tumor regrowth in the remnant capsule, which is recommended. Avoiding leakage of cyst fluid into the subarachnoid space helps to avoid postoperative chemical meningitis. Radiotherapy is an option for the management of multiple recurrences.

Keywords:

• epidermoid cyst
• conus medullaris
• cauda equina
• intramedullary

Abbreviations

CBC, complete blood count; CSF, cerebrospinal fluid; CT, computerized tomography; MRI, magnetic resonance imaging; T1W, T1-weighted images; T2W, T2-weighted images; DWI, diffusion-weighted images; L1, first lumbar vertebra; L2, second lumbar vertebra; L4, fourth lumbar vertebra; L5, fifth lumbar vertebra; CNS, central nervous system; EMG, electromyography; MEP, motor-evoked potential; SEP, sensory-evoked potential; CUSA, cavitron ultrasonic surgical aspirator.

Informed Consent

The participants’ parents consented to the publication of this case detail and accompanying images.

Disclosure

The authors declare that they have no conflicts of interest.