Abstract
Primary central nervous system lymphoma (PCNSL) is a rare disorder that, in 95% of cases, represents diffuse large B-cell lymphoma. As such, making an accurate diagnosis is important. At present, stereotactic-guided biopsy is a recognized method of choice for tissue analysis. However, the diagnostic work-up for high-risk patients is determined by their performance status. Here, we report a case of PCNSL in a high-risk patient, for whom diagnosis was established by cerebrospinal fluid cytology and flow cytometry, which significantly shortened a diagnostic work-up period and allowed for the immediate treatment of the patient.