Posterior Circulation Stroke in a Patient With May-Thurner Syndrome and Patent Foramen Ovale: A Case of Paradoxical Embolism.

Posterior circulation strokes can present with a range of subtle or fluctuating symptoms, often delaying diagnosis and complicating treatment decisions. We present the case of a 59-year-old woman with a prior history of transient ischemic attack (TIA), ischemic stroke, and antiphospholipid syndrome who was brought to the emergency department with acute dysarthria, vertigo, tinnitus, and vomiting. Imaging was initially unrevealing, but brain MRI confirmed acute infarcts in the superior vermis and right cerebellar hemisphere. Further workup revealed a patent foramen ovale (PFO) and May-Thurner syndrome (MTS), which were suspected contributors to a paradoxical embolic stroke. She underwent successful PFO closure and stent placement for left iliac vein compression. This case highlights the diagnostic challenge of posterior strokes and underscores the importance of considering underlying embolic and structural contributors in cryptogenic stroke presentations.