Dissecting aneurysm in the proximal region of the posterior inferior cerebellar artery presenting as Wallenberg's syndrome--case report.

A 29-year-old female presented with an unusual case of Wallenberg's syndrome due to a dissecting aneurysm of the posterior inferior cerebellar artery (PICA) manifesting as a sensation of heaviness in the occipital region and vertigo. Magnetic resonance imaging revealed infarction of the lateral aspect of the medulla oblongata. Digital subtraction angiography (DSA) revealed a spindle-shaped dilatation of irregular contour in the proximal portion of the left PICA. Pooling of contrast medium was noted in the venous phase but not double lumen sign. A suboccipital craniectomy confirmed these findings macroscopically. Blood flow meter monitoring before and after proximal clipping of the diseased vessel ensured the safety of the procedure. Follow-up DSA 3 years after surgery revealed no evidence of aneurysm recurrence.