Objective: Endodermal cysts are commonly found in the anterior spinal cord. Reports of intracranial cases are uncommon. We report a case of endodermal cyst located on the left oculomotor nerve.
Clinical presentation: A 16-year-old female experienced diplopia followed by headache. Neurological examinations revealed left oculomotor nerve palsy. Magnetic resonance imaging scans showed a well-defined multilocular cystic mass in the proximity of the left oculomotor nerve at its exit from the midbrain.
Intervention: This patient underwent biopsy and drainage of the cyst. At surgery, the cyst seemed to be intrinsic to the oculomotor nerve and could not be totally resected. Pathological examination confirmed the diagnosis of endodermal cyst.
Conclusion: Intracranial endodermal cysts are rare, particularly when associated with the cranial nerves. To our knowledge, this is the second case of endodermal cyst located on the oculomotor nerve. A detailed discussion and review of these case reports are presented.