Tumefactive Primary Central Nervous System Vasculitis: Imaging Findings of a Rare and Underrecognized Neuroinflammatory Disease

Abstract

Primary central nervous system vasculitis (PCNSV) is a poorly understood neuroinflammatory disease of the CNS affecting the intracranial vasculature. Although PCNSV classically manifests as a multifocal beaded narrowing of the intracranial vessels, some patients may not have angiographic abnormalities. A rare subset of patients with PCNSV present with masslike brain lesions mimicking a neoplasm. In this article, we retrospectively review 10 biopsy-confirmed cases of tumefactive PCNSV (t-PCNSV). All cases of t-PCNSV in our series that underwent CTA or MRA were found to have normal large and medium-sized vessels. T-PCNSV had a variable MR imaging appearance with most cases showing cortical/subcortical enhancing masslike lesion (70%), often with microhemorrhages (80%). Diffusion restriction was absent in all lesions. In summary, normal vascular imaging does not exclude the diagnosis of t-PCNSV. Advanced imaging techniques including MR perfusion and MR spectroscopy failed to demonstrate specific findings for t-PCNSV but assisted in excluding neoplasm in the differential diagnosis. Biopsy remains mandatory for definitive diagnosis.ABBREVIATIONS: PCNSV ¼ primary central nervous system vasculitis; t-PCNSV ¼ tumefactive PCNSV; ABRA ¼ amyloidb -associated angiitis; CAA-RI ¼ cerebral amyloid angiopathy-related inflammation; ESR ¼ erythrocyte sedimentation rate; MRP ¼ MR perfusion; CRP ¼ C-reactive protein; PCR ¼ polymerase chain reaction; VWI ¼ vessel wall imaging; PCNSL ¼ primary CNS lymphoma P rimary central nervous system vasculitis (PCNSV) is a poorly understood neuroinflammatory disease involving intracranial vessels. [1][2][3][4][5] The typical radiologic manifestation of PCNSV is multifocal beading of the large and medium-sized intracranial vessels. An underrecognized and rarer subset of PCNSV, approximately 5%-29%, can present with "masslike" or "tumefactive" lesions mimicking a neoplasm. 3,4,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] To date, imaging features of tumefactive PCNSV (t-PCNSV) have not been well described and definitive diagnosis can only be made confidently on histopathology. [5][6][7][8][9][10] In this article, we performed a retrospective review of 10 histopathologically proved cases of t-PCNSV and analyzed pertinent imaging features with histopathologic correlation. CASE SERIES Case SelectionWe performed a retrospective pathology data base search by using the keywords "brain biopsy" and "vasculitis" in histopathology reports from July 2010-December 2018 at a single institution. Exclusion criteria included patients with histopathology findings of amyloid-beta (Ab )-associated angiitis (ABRA) or cerebral amyloid angiopathy-related inflammation (CAA-RI), and infectious CNS vasculitis. Finally, we identified 6 patients who had a final diagnosis of t-PCNSV from this institution. The other 4 patients with t-PCNSV were collected from the imaging and histopathology archives of the contributing authors from 2 other institutions.All 10 patients presented with masslike brain...

Cerebral vasculitis of medium-sized vessels as a possible mechanism of brain damage in COVID-19 patients

“…Moreover, although the presence of angiographic abnormalities (including vascular irregularities, stenoses, aneurysms, and occlusions) is helpful in diagnosing cerebral vasculitis, these are usually described if larger vessels are involved, and a normal angiography does not rule out the diagnosis of vasculitis. 11 Concerning the cerebrospinal fluid analysis, only six patients suspected of cerebral vasculitis had a lumbar puncture, and SARS-CoV-2 RNA was never detected by RT-PCR, nevertheless, its absence does not exclude the diagnosis. First, it should be kept in mind that the lumbar punctures were performed late after SARS-CoV-2 infection (median of 28 days after the onset of respiratory symptoms).…”

Novel method using DW-MRI and ADC images to guide stereotactic biopsy for the diagnosis small primary angiitis of the central nervous system: A case report

“…As well as the traditional technologies of CT, MRI, and cerebrovascular imaging, such as computed tomography angiography (CTA), MRA, and digital subtraction angiography (DSA), the diagnosis of PACNS with various other imaging techniques has been reported, including new molecular imaging procedures [16][17][18] . Most PACNS patients have various MRI abnormalities 19 , but some PACNS patients have normal angiograms 20 . MRA and DSA examinations of PACNS patients can detect stenosis or dilation of multisegment blood vessels in ischemic lesions, but rarely nd long, complete vascular occlusions or aneurysm-like changes 1,6 .…”

“…Tissue biopsy is the key to diagnosing PACNS 26 , and the role of pathological biopsy in the diagnosis of PACNS is irreplaceable. Brain biopsy is now considered the 'gold standard' strategy for the de nitive diagnosis of PACNS 19 and should be pursued not only because it provides information that establishes the diagnosis but also effectively excludes other similar diseases 7,20,21,27 . Imaging methods cannot detect some cases of PACNS involving peripheral blood vessels.…”

Novel method using DW-MRI and ADC images to guide stereotactic biopsy for the diagnosis small primary angiitis of the central nervous system: A case report

“…As well as the traditional technologies of CT, MRI, and cerebrovascular imaging, such as computed tomography angiography (CTA), MRA, and digital subtraction angiography (DSA), the diagnosis of PACNS with various other imaging techniques has been reported, including new molecular imaging procedures [16][17][18] . Most PACNS patients have various MRI abnormalities 19 , but some PACNS patients have normal angiograms 20 . MRA and DSA examinations of PACNS patients can detect stenosis or dilation of multisegment blood vessels in ischemic lesions, but rarely nd long, complete vascular occlusions or aneurysm-like changes 1,6 .…”

“…Tissue biopsy is the key to diagnosing PACNS 26 , and the role of pathological biopsy in the diagnosis of PACNS is irreplaceable. Brain biopsy is now considered the 'gold standard' strategy for the de nitive diagnosis of PACNS 19 and should be pursued not only because it provides information that establishes the diagnosis but also effectively excludes other similar diseases 7,20,21,27 . Imaging methods cannot detect some cases of PACNS involving peripheral blood vessels.…”