Embolic Stroke in Setting of Iliac Vein Stenosis in an Avid Cyclist.

External iliac vein stenosis related to cycling has rarely been reported as a cause of deep vein thrombosis. Ischemic stroke occurring in this condition due to paradoxical embolism across a preexisting patent foramen ovale (PFO) has yet to be reported. Here we report a case of embolic ischemic strokes in a young, avid cyclist with no prior known vascular risk factors. A thorough cerebrovascular workup revealed a right-to-left shunt on transesophageal echocardiogram that prompted venous thrombosis evaluation. Pelvic MR venogram demonstrated a 3.5 cm high-grade stenosis of the right external iliac vein, concerning for possible prior thrombotic disease. His strokes were deemed most likely a result of paradoxical emboli originating in the pelvis at the site of right external iliac vein stenosis. The patient ultimately opted for PFO closure for secondary stroke prevention, as he wished to continue daily cycling. This case highlights the importance of neurohospitalists considering iliac vein stenosis as a potential cause of embolic stroke of undetermined source, especially in young patients who are avid cyclists, as part of a thorough vascular workup.