Neurosarcoidosis, the term used for sarcoidosis involving the central nervous system, represents an uncommon form of sarcoidosis, found in a 5% of patients with systemic sarcoidosis. Clinically evident cerebrovascular involvement in neurosarcoidosis has been reported but appears to be an extremely rare manifestation of neurosarcoidosis. The literature describes these cerebral vasculopathic changes as areas of stenosis and/or vascular irregularity, with clinical manifestations including headache, ischemic stroke, and parenchymal hemorrhage. Neurosarcoidosis has even been described as the etiology for a case of moyamoya syndrome.

In this case report, we describe a 43 year-old female with established pulmonary sarcoidosis presenting with aneurysmal subarachnoid hemorrhage in the setting of imaging findings indicative of vasculitic changes of neurosarcoidosis. Noninvasive vascular imaging demonstrated fusiform aneurysms of the proximal right AICA and PICA, within the region of thick subarachnoid hemorrhage, as well as nodular right inferior temproal leptomeningeal enhancement. Diagnostic catheter cerebral angiography confirmed these findings, also demonstrating areas of subtle vasculitic changes in an inferior temporal right MCA branch and a peripheral branch of the right AICA, corresponding to these areas of nodular leptomeningeal enhancement seen on MRI imaging. A combined approach was performed to treat the aneurysmal subarachnoid hemorrhage, which included deconstructive therapy (parent vessel occlusion) of the right AICA aneurysm followed by delayed reconstructive therapy (flow diversion) of the right PICA aneurysm. Reconstructive treatment was delayed primarily due to the need for dual antiplatelet treatment prior to performance of flow diversion. This delay allowed for evaluation and potential treatment of symptomatic hydrocephalus and vasospasm, as well as for extensive diagnostic evaluation of the underlying disease process. This workup included additional MRI sequences and diagnostic lumbar puncture that evaluated for infectious, inflammatory, and neoplastic etiologies. Flow cytometry was performed to evaluate for lymphoma, and a CSF angiotensin converting enzyme (ACE) level was performed to evaluate for neurosarcoidosis. Diagnostic testing was negative for infectious and neoplastic processes. The CSF ACE level was normal.

The patient recovered well from her subarachnoid hemorrhage and tolerated the combined aneurysm treatment without complication. Follow-up catheter cerebral angiography at 6 months demonstrated continued occlusion of the right AICA and its associated aneurysm, as well as wide patency of the right PICA flow diverter and thrombosis of the associated aneurysm. There continued to be mild vasculitic changes in the right inferior temporal region and right anterior inferior cerebellar region, unchanged. The patient continued to deny seizures or focal cranial nerve palsies. MRI imaging done at 6-month follow-up demonstrated stable leptomeningeal enhancement in the right inferior temporal region and right cerebellopontine angle. The patient's only clinical complaints at the time of 6-month follow-up was persistent intermittent right-sided headache. Due to the vasculitic changes and continued leptomeningeal enhancement, empiric treatment with oral steroids was initiated. Meningeal biopsy was not performed.

The above-described case report represents both the first reported case of neurosarcoidosis manifesting as aneurysmal subarachnoid hemorrhage, as well as the first case report of a fusiform PICA aneurysm treated with flow diversion.

Disclosures J. Gaughen: 2; C; Covidien, Microvention.