A Subacute Rupture of the Posterior Inferior Cerebellar Artery Pseudoaneurysm after a Mild Traumatic Brain Injury

The occurrence of intracranial traumatic pseudoaneurysm (TPA) in the posterior inferior cerebellar artery (PICA) is extremely rare. Management is challenging as it bears a high mortality. We encountered a case of PICA-TPA which was initially misdiagnosed as aneurysm pre-surgically. A 44-years old woman presented with sudden onset of change in mental status, headache and vomiting for 3 hours. She had a mild traumatic brain injury 6 weeks prior in a fall during which her left face hit the ground but no loss of consciousness or neurologic deficits. On examination, she exhibited stupor, GCS score = 9, with nuchal rigidity and abnormal Kernig sign but no other focal findings. Brain CT showed hemorrhage in the 3rd, 4th and bilateral ventricles with a small amount of subarachnoid hemorrhage. CT angiography and conventional angiography with digital subtraction angiography showed an aneurysm of 1.5 x 3.0 x 4 mm in size with a width of neck in 3 mm attached to the right PICA. Craniotomy was performed during which an olive-shaped pseudoaneurysm, partially muscular, with blood clot, 10 mm in length and 6 mm in diameter adhered to the surrounding brain tissue was visualized. This pseudoaneurysm was suddenly separated free from PICA and caused vigorous bleeding during the procedure. Directly suturing the ruptured wall of the PICA successfully stopped bleeding and sealed the PICA. The patient recovered well, no neurological deficits were recognized at discharge to home one week post-surgery. Repeat cerebral angiography showed a normal PICA in shape and length.