Recurrent Watershed Infarction Without Evident Intracranial Arterial Stenosis Due to Antiphospholipid Syndrome: A Case Report.

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by arterial, venous, or small vessel thromboembolic events. We present here a rare case of APS with repeated multiple cerebral infarctions in the same watershed area without visible arterial stenosis. A 53-year-old woman without a past medical history presented with a headache and numbness of the right fingers. Magnetic resonance imaging (MRI) showed acute ischemic lesions in the left middle cerebral artery (MCA) watershed area. Blood tests revealed positive anticardiolipin (aCL) and aCL beta-2-glycoprotein I antibodies (aCL-β2GPI). Three months later, aCL and aCL-β2GPi antibodies were still positive, and APS was confirmed.After four months from the index stroke, she was suddenly affected by right arm and leg weakness under a warfarin prescription. Brain MRI showed a recurrence of acute ischemic stroke in the same left MCA watershed area and the right cerebellar hemisphere without visible intracranial artery stenosis in magnetic resonance angiography. The examination of carotid ultrasonography, electrocardiogram monitoring, as well as transthoracic and transesophageal echocardiography revealed no abnormalities, indicating that the recurrent ischemic stroke was due to APS. Single-photon emission-computed tomography captured wide hypoperfusion beyond the infarction area. Thus, the stroke may have been caused by a repeated thromboembolic mechanism. In conclusion, APS should be considered a differential diagnosis in repeated watershed strokes without obvious intracranial arterial stenosis.