Pearls & Oy-sters: Tumour-Like Mass Lesion Secondary to Primary CNS Vasculitis.

in Neurology by Jodie I Roberts, Denise Ng, Ronak Kapadia

TLDR

  • Tumefactive primary CNS vasculitis (PCNSV) is a rare condition where the blood vessels in the brain become inflamed. This can cause symptoms like seizures and difficulty moving. The study is about a man who had these symptoms and was initially thought to have a tumor, but further testing showed that he actually had PCNSV. The study highlights that PCNSV can look like a tumor on imaging tests, but there are specific features that can help doctors tell the difference. The study also emphasizes the importance of distinguishing PCNSV from other conditions, like CNS lymphoma, which can have similar symptoms and imaging findings. The study suggests that more research is needed to better understand PCNSV and develop better treatments.

Abstract

Primary CNS vasculitis (PCNSV) is uncommonly considered in the differential diagnosis of tumor-like lesions. This case report of tumefactive PCNSV highlights imaging features that should increase clinical suspicion for CNS vasculitis, potentially lending to earlier diagnosis and treatment. A 62-year-old man presented with a 1-month history of focal motor seizures and cortical sensory loss localizing to the right frontoparietal lobe. Noncontrast head CT was suggestive of glioma, resulting in intravenous dexamethasone administration and admission to neurosurgery. MRI appearance was atypical for glioma, with relative preservation of regional anatomy, intralesional microhemorrhage, and patchy peripheral enhancement. Despite normal CT angiogram, CSF, and serum inflammatory markers, brain biopsy was suggestive of lymphocytic vasculitis. Extensive workup for secondary causes was negative, and he was diagnosed with tumefactive PCNSV. Treatment with corticosteroids and cyclophosphamide resulted in sustained clinical and radiologic improvement. Tumefactive PCNSV is an angiogram-negative small-vessel vasculitis that has a lymphocytic histologic pattern. Tumefactive PCNSV constitutes over 10% of PCNSV cases and can be recognized by the presence of intralesional microhemorrhages, absence of diffusion restriction, and a patchy or nodular enhancement pattern. The most important mimicker is CNS lymphoma, which has a similar imaging and histologic pattern. If individuals with tumefactive PCNSV do not have a sustained immunotherapy response, repeat biopsy should be promptly performed.

Overview

  • The study focuses on a case report of tumefactive primary CNS vasculitis (PCNSV) in a 62-year-old man with focal motor seizures and cortical sensory loss localizing to the right frontoparietal lobe. The study aims to highlight imaging features that should increase clinical suspicion for CNS vasculitis, potentially leading to earlier diagnosis and treatment. The methodology used includes noncontrast head CT, MRI, CSF, serum inflammatory markers, and brain biopsy. The primary objective is to diagnose the patient with tumefactive PCNSV and demonstrate the effectiveness of corticosteroids and cyclophosphamide in treatment.

Comparative Analysis & Findings

  • The study compares the imaging findings of the patient with tumefactive PCNSV to those of glioma and CNS lymphoma. The MRI appearance of the patient's lesion was atypical for glioma, with relative preservation of regional anatomy, intralesional microhemorrhage, and patchy peripheral enhancement. The absence of diffusion restriction and a nodular enhancement pattern further supported the diagnosis of tumefactive PCNSV. The study found that the most important mimicker of tumefactive PCNSV is CNS lymphoma, which has a similar imaging and histologic pattern. The study demonstrates that tumefactive PCNSV can be recognized by the presence of intralesional microhemorrhages, absence of diffusion restriction, and a patchy or nodular enhancement pattern.

Implications and Future Directions

  • The study highlights the importance of recognizing tumefactive PCNSV in the differential diagnosis of tumor-like lesions. The study's findings suggest that imaging features, such as intralesional microhemorrhages, absence of diffusion restriction, and a patchy or nodular enhancement pattern, can increase clinical suspicion for CNS vasculitis. The study also emphasizes the importance of distinguishing tumefactive PCNSV from CNS lymphoma, which has a similar imaging and histologic pattern. Future research should focus on developing more specific imaging and histologic markers for tumefactive PCNSV to improve diagnosis and treatment. Additionally, further studies are needed to determine the optimal treatment regimen for tumefactive PCNSV, particularly in cases where immunotherapy does not result in a sustained response.
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