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, while 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 an incomplete patients counselling before surgery. CASE DESCRIPTION: We report two cases of a patient with oculomotor schwannoma and a patient with oculomotor neurofibroma. After tumor resection, patient with a diagnosis of schwannoma recovered is 3(rd) 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 (MRI) 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 MRI guides in distinguishing the different histology, in selecting the treatment strategy and to correctly inform the patient on expected postoperative neurological outcome.