Oculomotor nerve tumors masquerading as recurrent painful ophthalmoplegic neuropathy: Report of two cases and review of the literature

In recurrent painful ophthalmoplegic neuropathy (RPON) that was previously termed as ophthalmoplegic migraine, enhancement of the ocular motor cranial nerves could be seen in the cisternal segment during the acute phase. However, various tumors involving the oculomotor nerve may mimic RPON.We report two patients with MRI findings of oculomotor nerve schwannoma who initially presented with RPON, and found through the literature review five more patients with oculomotor nerve tumors that masqueraded as RPON.All patients showed an involvement of the oculomotor nerve. The radiological or pathological diagnosis included schwannoma in five, venous angioma in one, and neuromuscular harmatoma in another one. MRIs with gadolinium documented an enhancing nodule involving the cisternal portion of the oculomotor nerve in six of them, which was also observed on follow-up MRIs without an interval change.It should be recognized that an incomplete recovery may occur during future attacks in patients with otherwise uncomplicated RPON. Follow-up MRIs are required to detect tumors involving the ocular motor cranial nerves, especially in patients with suspected RPON when the recovery is incomplete.