A 34-year-old woman with history of migraines without aura had sudden onset of loss of peripheral vision of her right visual field. She also experienced a brief episode of horizontal diplopia and bifrontal headaches. She did not have nausea, vomiting, photophobia, phonophobia, or osmophobia.

Our patient had an isolated congruous right homonymous hemianopia due to an occlusion of cortical branches of the left posterior cerebral artery (PCA). A unilateral PCA infarction often results in contralateral homonymous hemianopia with macular sparing. The extracranial vertebral arteries were unremarkable. Magnetic resonance angiography (MRA) showed an occluded P2 segment with no visualization of the calcarine artery, parietooccipital artery, and posterior temporal artery.

Further investigations failed to demonstrate a possible cardiac source of embolism. As shown by the MRA, she had no evidence of proximal vertebrobasilar steno-occlusive disease nor evidence of intrinsic atheromatous disease of the PCA. She did not smoke cigarettes and was not on oral contraceptives. Although she had a history of migraine headaches, and cerebral infarctions complicating migraine mostly involve the PCA distribution, she was found to have persistent elevations of antiphospholipid antibodies titer. Her infarction was ultimately attributed to a prothrombotic state due to a primary APAS.