Isolated angiitis of the central nervous system with tumor-like lesion, mimicking brain malignant glioma: a case report and review of the literature

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

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.

Characteristics of mass lesion presentation of primary angiitis of the central nervous system: A single center 11-year retrospective case-series study

OBJECTIVE

Mass lesion presentation of primary angiitis of the central nervous system (ML-PACNS) is a special subtype of primary central nervous system vasculitis, which is difficult to be differentiated from other space-occupying disorders. We aimed to summarize our experience and improve diagnostic techniques of ML-PACNS.

PATIENTS AND METHODS

Case records for 16 patients treated in the Department of Neurology of Six Medical Center of Chinese PLA General Hospital from December 2008 to November 2019 were examined. All patients were diagnosed with ML-PACNS by pathology. Clinical manifestations, neuroimaging results and pathological features were retrospectively analyzed.

RESULTS

The 16 patients with ML-PACNS in the cohort (8 males) had a median age of 32 (range 19-56 years). On T1WI and T2WI, 12 cases showed mixed signals and 4 cases showed T1WI hypointense and T2WI hyperintense. Fifteen patients showed DWI hyperintense, of which 9 cases showed hypointense in the middle of the lesion. Gadolinium enhancement of all cases was irregular. All patients had a brain biopsy (stereotactic procedure in 10 and open-wedge surgery in 6) which showed lymphocytic vasculitis in the majority of patients (15/16) and necrotizing vasculitis in one patient.

CONCLUSIONS

ML-PACNS is an important differential candidate for tumefactive demyelinating lesions, CNS infections and brain tumors. Mixed T1WI and T2WI signals as well as central hypointense surrounded by hyperintense lesions on DWI may be useful imaging features for the diagnosis of ML-PACNS which has implications for those who have not yet had a biopsy. ML-PACNS may have different pathological type from PACNS.

Primary Angiitis of the Central Nervous System Mimicking Glioblastoma: A Case Report and Literature Review

Primary angiitis of the central nervous system (PACNS) is a rare disorder resulting in idiopathic inflammation affecting the parenchymal and leptomeningeal vessels confined to the central nervous system (CNS), of which a tumor-like mass lesion is an even rare subtype. We described a case of PACNS initially misdiagnosed as glioblastoma. The patient was a 35 year-old female with right-sided weakness and expressive dysphasia. Brain MRI showed a tumor-like lesion highly suggestive of glioblastoma, therefor surgical removal was done. After a resection and an exhaustive workup, PACNS was ultimately diagnosed. The case illustrates a type of imaging presentation of PACNS that is often misdiagnosed as high-grade glioma. Differentiation between tumor-like PACNS lesions and actual CNS tumors is challenging due to similar MR images. To avoid unnecessary surgical interventions, we summarized previously reported mass-forming PACNS cases in adults from January 1, 2000, to December 31, 2018 and the imaging characteristics of PACNS. Some less commonly used diagnostic methods such as MR spectroscopy may also help clinicians distinguish PACNS from its mimics.

Primary CNS vasculitis masquerading as glioblastoma: A case report and review

Isolated angitis of the central nervous system (IACNS)/primary angitis of central nervous system vasculitis (PACNS) is an uncommon vascular disease, sparingly presenting as an isolated inflammatory lesion on magnetic resonance imaging (MRI). The disease usually manifests as a long-drawn and progressive ischemic event. Delay in diagnosis due to focal nature of the lesion also contributes to the poor prognosis as the dismal natural history and immunosuppressive therapy. To date, only a few cases with tumor-like isolated angitis of CNS have been reported with clear and definitive diagnostic workup.

Primary angiitis of the central nervous system presenting as a mass lesion

We report a 51-year-old Asian man with primary angiitis of the central nervous system (PACNS) with atypical presentation as a mass lesion. PACNS is an uncommon condition causing inflammation and destruction of the blood vessels of the central nervous system. The aetiology is unclear and multiple mechanisms have been proposed. Its incidence is estimated at 2.4 per million per year, affecting patients of all ages (median 50 years) and more commonly Caucasian men. In Australia, 12 patients fulfilled the diagnostic criteria for PACNS between 1998 and 2009 at The Royal Melbourne Hospital, a university-affiliated tertiary referral centre. The accurate and timely diagnosis of PACNS is very challenging due to disease mimicry and the absence of specific serological tests. This patient illustrates additional diagnostic difficulty with his atypical PACNS presentation as a mass lesion.

Interference of Notch 2 inhibits the progression of gliomas and induces cell apoptosis by induction of the cell cycle at the G0/G1 phase

Glioblastoma is the most common type of malignant brain tumor with a poor prognosis. The Notch signaling pathway is often aberrantly activated in glioma cells. In order to determine the expression of Notch 2 and to evaluate its possible prognostic value in malignant glioblastoma, specimens from 32 patients and 20 controls were analyzed using immunohistochemical staining and reverse transcription quantitative polymerase chain reaction. The expression of Notch 2 in the glioma tissues was significantly higher compared with that in the normal brain tissues (P<0.01). Subsequently, endogenous Notch 2 interference was effectively performed by specific small hairpin (sh)RNA in the glioma cancer cell line U251. The results from an MTT assay and from Annexin V-fluorescein isothiocyanate/propidium iodide staining indicated that interference of Notch 2 significantly inhibited the proliferation and induced the apoptosis of U251 cells. In addition, the cell cycle was analyzed using flow cytometry and the results revealed that Notch 2 shRNA induced cell cycle arrest at the G0/G1 phase in U251 cells. Additionally, proteins associated with the cell cycle and cell proliferation were detected using western blot analysis. The data demonstrated that the expression of P21, cyclin D and phosphorylated retinoblastoma was significantly inhibited in the Notch 2 shRNA-transfected U251 cells. The results of the present study provide further insights into the effects of Notch 2 and a molecular reference for brain tumor therapy.

Cerebral tumor or pseudotumor?

Pseudotumoral lesions are uncommon but important to identity lesions. They can occur during inflammatory diseases (systemic diseases, vasculitis, demyelinating diseases), infectious, and vascular diseases. Also, in a patient with a treated tumor, pseudo-progression and radionecrosis must be differentiated from the tumoral development. Diagnosis can be difficult on an MRI scan, but some MRI aspects in conventional sequences, diffusion, perfusion and spectroscopy can suggest the pseudotumoral origin of a lesion. Imaging must be interpreted according to the context, the clinic and the biology. The presence of associated intracranial lesions can orientate towards a systemic or infectious disease. A T2 hyposignal lesion suggests granulomatosis or histiocytosis, especially if a meningeal or hypothalamic-pituitary involvement is associated. Non-tumoral lesions are generally not hyperperfused. In the absence of a definitive diagnosis, the evolution of these lesions, whether under treatment or spontaneous, is fundamental.

Intravascular lymphomatosis mimicking primary central nervous system lymphoma: a case report and literature review

We herein report a 75-year-old female patient with intravascular lymphomatosis (IVL) who presented with fever of unknown origin. Examination, including contrast-enhanced CT and (67)Ga scintigraphy, failed to show any lesions. Her blood levels of lactate dehydrogenase and soluble interleukin-2 receptors were high, suggesting a lymphomatous tumor. A bone marrow puncture was negative, and a random skin biopsy revealed a monoclonal proliferation of naked, large lymphocytes in the vascular space of the subcutaneous tissue, confirming the diagnosis of IVL. MRI, performed 7 weeks after admission, showed a brain mass mimicking primary central nervous system lymphoma. The mass was considered to be a collection of malignant lymphocyte cells invading from the vessels. Without the random skin biopsy, this case may have been misdiagnosed as primary central nervous system lymphoma.