Lacunar syndrome associated with paradoxical brain embolism.

We report a patient who developed lacunar syndrome due to left upper pons infarction after performing leg exercises associated with paradoxical brain embolism. A 32-year-old man developed right arm weakness and moderate dysarthria following leg exercise. Brain MRI showed a paramedian pontine infarction of the left upper pons, and contrast transesophageal echocardiographic examination indicated that the patent foramen ovale was the embolic source. Simultaneous RI venography examination of the lower limbs identified deep venous thrombosis in the right leg as a paradoxical emboligenic source. We concluded that the presence of lacunar syndrome suggests that this mechanism was responsible for the paradoxical brain embolism.