Isolated Intracranial Fibromuscular Dysplasia in an Older Adult Male: Systematic Review and Case Report

Background: While fibromuscular dysplasia (FMD) can affect vessels throughout the body, isolated intracranial FMD strictly impacts the vessels within the skull and remains underdiscussed in the literature. Knowing more about the presentation of this subtype of FMD would assist in improving patient outcomes. 

Methods: A previously unpublished case of isolated intracranial FMD in a 76-year-old man was retrospectively reviewed. In addition, a systematic review was conducted in accordance with PRISMA guidelines. Studies were included if they detailed cases of isolated intracranial FMD and were excluded if extracranial involvement was found or was not ruled out. Cases were summarized and aggregated for descriptive analysis. 

Results: After reviewing 403 manuscripts, a total of 13 cases of isolated intracranial FMD were found in the literature, with our case representing the 14^th case. Mean patient age was 28.1 years, and 42.9% of patients were male. Common symptoms at patient presentation included headache (64.3%), hemiparesis/hemiplegia (35.7%), and dysarthria/dysphagia/aphasia (35.7%). 71.4% of cases were diagnosed by cerebral angiography, with the remaining cases found at autopsy. All patients were found to have a stroke (71.4%) or subarachnoid hemorrhage (SAH; 28.6%) involving the middle cerebral (64.3%), intracranial internal carotid (50.0%), or basilar artery (14.2%). While 21.4% of patients experienced a complete recovery, 21.4% died during hospitalization, and 42.9% were found to have persistent functional impairment on follow-up.  

Conclusions: Isolated intracranial FMD is a rare but serious subset of FMD. Patients tend to be younger than those who experience extracranial FMD and have more severe presentations including stroke and subarachnoid hemorrhage. While more research is needed to better understand the pathophysiology and management of this disease, current literature underscores its impact on patient morbidity and mortality. In young patients and patients with unexplained stroke or SAH, cerebral angiography may be warranted to examine for isolated intracranial FMD.