Describe CT and MRI findings which allow for the establishment of a more accurate differential diagnosis between primary central nerve system lymphoma (PCNSL) and other entities such as glioblastoma or metastasis.

PCNSL represents 1-6% of malignant CNS tumors. They are usually Non-Hodgkin lymphomas and occur among people aged 50 and over. The most frequent clinical presentation is neurological, followed by neuropsychiatric symptoms and intracranial hypertension. They are typically supratentorial and can appear as a single mass or as multiples masses (most common amongst immunocompromised patients). Differential diagnosis with glioblastoma and metastasis is sometimes difficult.

We revised CT and MRI findings in 6 patients diagnosed with PCNSL at our centre in the last 5 years. CT and a conventional sequences-MRI were performed on all of them. We also used more advanced techniques (spectroscopic and perfusion MRI) on 3 of them. PET-CT was used in 3 patients to rule out systemic involvement. In 6 the diagnosis was reached by biopsy, and in 1 case through a specific study of the cerebroespinal fluid. Case1: Fig. 1 We report a case of a...

Even though PCNSL has no typical imaging pattern, classically multiple imaging findings have been reported to reach a diagnosis. The imaging findings in our center were: Hyperdense lesions on brain CT scan without contrast. Intense and homogeneous enhancement pattern on CT scan without contrast. The lesions had restricted diffusion in 75% of the cases who had solitary lesions. Solitary lesion with supratentorial location. No associated intracranial hemorrhage.

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