Adult-onset recurrent painful ophthalmoplegic neuropathy displaying atypical oculomotor nerve gadolinium-enhancement pattern in the orbit and cavernous sinus.

Dear Editor, We read with great interest the review article in Cephalalgia entitled ‘Ophthalmoplegic migraine: From questions to answers’ by Ambrosetto et al. (1). The authors pointed out that, in adult-onset recurrent painful ophthalmoplegic neuropathy (RPON, code 13.9 of ICHD-3 beta), the magnetic resonance imaging (MRI) finding shows no gadolinium enhancement or nerve thickening. We experienced an adult-onset case of RPON in which fat-suppressed post-contrast T1weighted imaging (T1WI) and T2-weighted imaging (T2WI) were useful in detecting lesions within the orbit and cavernous sinus. A 42-year-old woman presented with recurrent throbbing headaches in the right occiput followed by right ptosis and ophthalmoparesis of inward and vertical movements. She experienced these symptoms approximately 30 times in the 22 years since the first attack. The symptoms resolved within two months. After excluding cerebral aneurysm, Tolosa–Hunt syndrome, sarcoidosis, diabetes, thyroid dysfunction, collagen diseases and meningitis, we diagnosed RPON. Ten cranial MRI examinations were conducted over six years using a 1.5-T unit. High spatial resolution thin-slice fat-suppressed T2WI was added to conventional whole brain MRI in six examinations. Only one conventional whole-brain MRI detected slight abnormal enhancement of the right oculomotor nerve at the root exit zone that was performed one week after the onset of oculomotor symptoms (Figure 1(a)). In contrast, obvious enhancement of the right oculomotor nerve within the orbit and cavernous sinus was identified in all high-resolution fat-suppressed postcontrast T1WIs of the orbit performed during an ictal period (Figure 1(b)). The magnitude of enhancement was greater 1 week after the onset of the oculomotor symptoms compared with that after three and eight weeks. The enhancement disappeared during the interictal period. Further, fat-suppressed T2WIs of the orbit and cavernous sinus showed swelling and abnormal hyperintensities of the oculomotor nerve during a paroxysmal period (Figure 1(c)). These alterations emerged in parallel with the disease activity. It is noteworthy that conventional whole-brain T2WIs did not detect such abnormalities. RPON, formerly known as ophthalmoplegic migraine, is a rare disorder and its onset occurs usually