Intrinsic hematoma of the oculomotor nerve: Case report and review of the literature

OBJECTIVE AND IMPORTANCE: Intrinsic oculomotor nerve hematoma is an exceptional cause of third nerve palsy. This case report illustrates the clinical, radiological, and intraoperative relevance of this rare pathological finding. CLINICAL PRESENTATION: A 25-year-old woman with a 12-year history of gross total resection of cerebellar medulloblastoma and posterior whole-brain radiotherapy presented with complete left oculomotor palsy. Magnetic resonance imaging revealed a left-sided, perimesencephalic cistern, small, round lesion with a fluid level. Digital subtraction angiography demonstrated no evidence of vascular abnormalities. INTERVENTION: A pterional craniotomy was performed, and the left oculomotor nerve was exposed. A blackish intrinsic lesion was detected in its cisternal segment near the uncus. The lesion was incised, and liquid compatible with a subacute noncoagulated hematoma was drained. Three months after surgery, the patient had partial recovery from diplopia and extraocular muscle function. CONCLUSION: We reviewed the literature and found four cases of oculomotor nerve intrinsic hematoma. These cases were all associated with hematological diseases, trauma, or solid tumors, and, as a group, these patients had poor outcomes. In the present report, the possibility of radiotherapy-induced vasculopathy as a predisposing factor is discussed. Surgical removal of an intrinsic nerve hematoma is probably helpful in the functional recovery of these patients.