Primary Central Nervous System Lymphoma: Diffusion Weighted Imaging and Spectroscopy

Primary central nervous system lymphoma (PCNSL) is most commonly confused with high grade glial tumors. One third of all cases were misdiagnosed with neuroradiological procedures. The recommended treatment modality is chemotherapy and radiotherapy in contrary to high grade gliomas. It is important to differentiate lymphoma and high grade glial tumors. The latest studies demonstated the beneficial role of advanced neuroradiological procedures like diffusion weighted imaging (DWI), apparent difusion coefficient map (ADC) and spectroscopy. The cranial MRI study with conventional sequences showed a mass lesion which invaded the corpus callosum and the ventricule in a 70-year old man. It was hyperintense on DWI images compared to white matter and iso- mildly hypointense on ADC map. There was a decrease in N-acetyl aspartate (NAA) and creatine peak and an increase in the choline peak. A remarkable lipid peak was present. The differential diagnosis included lymphoma primarily. The diagnosis was diffuse B cell lymphoma after histopathological evaluation. Our purpose in this study is to emphasize the importance of DWI, ADC map and spectroscopy in addition to conventional MRI sequences.