CANOMAD Presenting as Bilateral Sixth Nerve Palsies

A 67-year-old man reported 1 day of binocular horizontal diplopia associated with 1 week of bilateral periorbital pain, worse in the right eye. He felt otherwise well without any constitutional symptoms. Four days prior, he had undergone a partial right nephrectomy for grade II papillary renal cell carcinoma. Visual acuity was 20/20 in each eye, and the remainder of his ophthalmic examination was normal except for mildly limited abduction bilaterally, with a 16-prism diopter esotropia in primary gaze. Brain MRI, acetylcholine receptor antibodies, and thyroid-stimulating hormone level were normal.