The Multiple Faces of Nervous System Lymphoma. Atypical mri Features and Contribution of the Advanced Imaging

Primary central nervous system lymphoma (PCNSL) is an uncommon variant of extranodal non-Hodgkin lymphoma (NHL) that involves the brain, leptomeninges, eyes or spinal cord without evidence of systemic disease. In addition to a detailed history and physical examination, the evaluation of patients suspected of having a PCNSL should include a contrast enhanced MRI. Occassionaly PCNSL shows peculiarities on MRI, which delay the diagnosis and thus the start of treatment. It is essential that radiologists be aware of these less common presentations, such as isolated spine or meningeal lymphoma, angiocentric lymphoma, ocular lymphoma and Epstein-Barr virus-associated lymphoma. Advanced neuroimaging (diffusion and perfusion sequences, spectroscopy-MR and positron emission tomography metabolic imaging) are useful techniques for the differential diagnosis of PCNSL with processes such as brain glioblastoma, multiple sclerosis, metastases and brain abscesses, specially in atypical presentations. In this article, a review of unusual radiological findings for PCNSL in immunocompetent patients is made, highlighting the usefulness of functional and metabolic imaging for establishing an early presumptive diagnosis, which reduces delays in treatment