[Subarachnoid hemorrhage due to a ruptured intracranial vertebral artery aneurysm associated with cerebrovascular fibromuscular dysplasia: case report].

Fibromuscular dysplasia (FMD) is comprised of a group of nonatherosclerotic and noninflammatory arterial diseases. Cerebrovascular FMD occurs more frequently in women, and the mean age at which it is diagnosed is 50 years. The most common angiographic pattern of cerebrovascular FMD is the "string-of-beads" deformity at the extracranial internal carotid artery. We report the case of a 52-year-old woman who presented with a sudden severe headache and went into a deep coma. She had been complaining of headaches for 2 weeks, but no specific imaging findings were obtained. A computed tomography scan obtained on admission showed a diffuse subarachnoid hemorrhage (SAH) from the cerebellomedullary cistern to the basal cistern with evidence of clot in the fourth and third ventricles. We performed digital subtraction angiography and made the diagnosis of cerebrovascular FMD. Right carotid angiography and left vertebral angiography showed the classic "string-of-beads" pattern with multiple constrictions of the lumen. Left carotid angiography showed a long segment of tubular stenosis. Right vertebral angiography also revealed the "string-of-beads" pattern and a ruptured aneurysm at the intracranial segment, which presented as a diverticulum-like outpouching. The patient was treated with conservative measures but passed away on the 23rd day of hospitalization. An autopsy was not performed. To our knowledge, during the last three decades, there are only four previous reports which showed intracerebral ruptured aneurysms of the vertebral artery or its branch in adults with cerebrovascular FMD. We demonstrate and discuss the radiologic findings here.