Lymphomatosis Cerebri: A diagnostic dilemma

Background Lymphomatosis cerebri (LC) is a rare manifestation of primary central nervous system lymphoma (PCNSL) with only a few cases reported in the literature, appearing as diffuse infiltrating process rather than a solitary mass. It is a non-Hodgkin’s type of lymphoma and is usually of the B-cell type origin. Purpose We intend to report this unique case of LC which came across as a diagnostic challenge. Methods A 53-year-old gentleman presented with complaints of two episodes of seizures 24 h apart followed by postictal confusion for 10–15 min. He underwent multiple MRI scans and underwent a biopsy of the lesion which reported infection, but he did not benefit from the treatment. Result The imaging was reviewed, suspicion of LC was raised and a review of histopathology was requested which later confirmed primary CNS lymphoma. Conclusion LC is a rare but established manifestation of PCNSL which mimics multiple other conditions. Understanding of the imaging pattern is important in making the diagnosis and differentiating it from other mimic conditions.