Oculomotor Neurofibroma: A Different Histology Implying an Unsatisfying Clinical Outcome.

BACKGROUND: Tumors arising from oculomotor nerve are rare, with few cases reported in the literature. Generally, whereas schwannomas are well encapsulated tumors, neurofibromas tend to invade the entire nerve fibers. These differences influence surgical resection and neurological clinical outcome, with neurofibroma often requiring the sacrifice of the nerve. Accordingly, an incorrect preoperative diagnosis can lead to incomplete patient counseling before surgery. CASE DESCRIPTION: We report 2 cases: a patient with oculomotor schwannoma and a patient with oculomotor neurofibroma. After tumor resection, the patient with a diagnosis of schwannoma recovered with 3rd nerve palsy, while patient with the neurofibroma developed a complete oculomotor nerve deficit. For each patient, surgical strategy and neurological outcome are elucidated in relation with differences in preoperative magnetic resonance imaging and histology.
CONCLUSIONS: To the best of our knowledge, this is the first report of an oculomotor neurofibroma. When an oculomotor nerve tumor is suspected, a careful preoperative evaluation of magnetic resonance imaging guides in distinguishing the different histology, in selecting the treatment strategy, and in correctly informing the patient on expected postoperative neurologic outcome.