Learning objectives
To review the differential diagnosis of cerebral ring-enhancing (RE) lesions
A comprehensive approach to etiologies of RE lesions considering both clinical and radiological findings
Background
RE lesions, as one of the most common lesions encountered in neuroimaging, have a broad differential diagnosis. The most common etiologies are high-grade glioma (40%), metastases (30%), abscess (8%), and demyelinating disease (6%) [1]. Other conditions such as radiation necrosis may manifest as RE lesions. In immunocompromised patients primary central nervous system lymphomas(PCNSL) and opportunistic infections should be considered.
To distinguish between neoplastic and non-neoplastic conditions the size, number and location of lesions, enhancing characteristics and extent of surrounding edema should be considered as well...
Findings and procedure details
Although nonspecific, there are some guiding features of RE lesions to rule out some from the long list of etiologies.
Irregular RE, hypodense center representing necrosis, marked surrounding vasogenic edema and deep location are typical for primary central nervous system neoplasms such as Glioblastoma.
Metastases are usually multifocal, similar-sized lesions with usually no diffusion restriction.
Multifocal lesions with thin RE, T2 hypointense rim, diffusion restriction, and extensive surrounding edema are favorable for abscesses. Gray-white matter junction location is typical for hematogenous dissemination of both metastatic...
Conclusion
Since RE lesions are similar in appearance on different radiologic modalities, they can be challenging in terms of diagnosis. So one should be aware of the key findings and clinical clues to prevent unnecessary invasive diagnostic methods.
Personal information and conflict of interest
M. Yalçın; Istanbul/TR - nothing to disclose K. Harmanci; Istanbul/TR - nothing to disclose
References
1. Schwartz KM, Erickson BJ, Lucchinetti C. Pattern of T2 hypointensity associated with ring-enhancing brain lesions can help to differentiate pathology. Neuroradiology 2006; 48: 143-149.
2. Garg R K, Sinha M K. Multiple ring-enhancing lesions of the brain. J Postgrad Med 2010;56:307-16 .
3. Rong Y, Durden DL, Van Meir EG, Brat DJ. ‘Pseudopalisading’ necrosis in glioblastoma: a familiar morphologic feature that links vascular pa- thology, hypoxia, and angiogenesis. J Neuropathol Exp Neurol 2006;65:529 –539.
4. Kumar V, Abbas AK, Fausto N et-al. Robbins and...
