EXTRACRANIAL ANEURYSM OF THE POSTERIOR INFERIOR CEREBELLAR ARTERY WITH AN ABERRANT ORIGINATIONCASE REPORT

OBJECTIVE: Aneurysms of the extracranially originating posterior inferior cerebellar arteryare very rare. An anatomic insight of its possible course and variations is necessary when confronting such extraordinary lesions. CLINICAL PRESENTATION: A 19-year-old man presented with the sudden onset of severe headaches. A physical examination was positive onlyfor neck rigidity. Computed tomographic scans of the brain depicted intraventricular hemorrhage. TECHNIQUE AND INTERVENTION: Four-vessel brain digital subtraction angiographyrevealed an extracranial posterior inferior cerebellar arteryarising extradurally from the right vertebral arterybetween the C1 and C2 vertebrae, bearing a saccular aneurysm in an upper cervical intradural location. An anterior inferior cerebellar artery- posterior inferior cerebellar arteryvariant was also found on the left side. Computed tomographic angiography failed to unmask the lesion. The aneurysm was clipped through a suboccipital craniectomy and C1 laminectomy. CONCLUSION: The patient did well after surgery and was discharged from the hospital without neurological deficit. One can conclude that a comprehensive diagnostic approach oriented to the patient history and clinical data is mandatory to preclude such lesions evading the vigilant surgeon.