A rare case of nonenhancing primary central nervous system lymphoma mimic multiple sclerosis.

Primary central nervous system lymphoma (PCNSL) is reported to have increased in the last decades. Early diagnosis is crucial for proper management of this tumor. We report a case of a 48-year-old man who was initially diagnosed with multiple sclerosis. Magnetic resonance imaging of the brain revealed multiple lesions with hyper-signals in the bilateral basal ganglia and brain stem in T2-weighted image and non-enhancement, while positron emission tomography showed a low uptake of 18F-fluorodeoxyglucose in the affected brain, indicative of demyelination. However, this individual was correctly diagnosed with PCNSL after biopsy and further histological analysis. Primary central nervous system lymphoma must be considered even when nonenhancing, diffuse lesions are seen on MRI. A visible tumor on imaging is essential to ensure an early brain biopsy and histological diagnosis.