Diagnosis of primary central nervous system lymphoma: a systematic review of the utility of CSF screening and the role of early brain biopsy

Background Because less-invasive techniques can obviate the need for brain biopsy in the diagnosis of primary central nervous system lymphoma (PCNSL), it is common practice to wait for a thorough initial work-up, which may delay treatment. We conducted a systematic review and reviewed our own series of patients to define the role of LP and early brain biopsy in the diagnosis of PCNSL. Methods Our study was divided into 2 main sections: 1) systematic review assessing the sensitivity of cerebrospinal fluid (CSF) analysis on the diagnosis of PCNSL, and 2) a retrospective, single-center patient series assessing the diagnostic accuracy and safety of early biopsy in immunocompetent PCNSL patients treated at our institution from 2012 to 2018. Results Our systematic review identified 1481 patients with PCNSL. A preoperative LP obviated surgery in 7.4% of cases. Brain biopsy was the preferred method of diagnosis in 95% of patients followed by CSF (3.1%). In our institutional series, brain biopsy was diagnostic in 92.3% of cases (24/26) with 2 cases that required a second procedure for diagnosis. Perioperative morbidity was noted in 7.6% of cases (n = 2) due to hemorrhages after stereotactic brain biopsy that improved at follow-up. Conclusions The diagnostic yield of CSF analyses for PCNSL in immunocompetent patients remains exceedingly low. Our institutional series demonstrates that early biopsy for PCNSL is safe and accurate, and may avert protracted work-ups. We conclude that performing an early brain biopsy in a suspected case of PCNSL is a valid, safe option to minimize diagnostic delay.