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

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. 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. 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. 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.