Introduction Primary Central Nervous System lymphoma (PCNSL) is responsible for 5% of all primary brain tumours within the UK. Barriers to diagnosis include steroid-responsiveness/false-negative biopsy and poor CSF sensitivity. We performed a pilot audit reflecting 5 years experience of PCNSL diagnosis based on criteria derived from 2011 British Neuro-Oncology guidelines.

Methods Retrospective case note and electronic patient record review for patients between 2008 to 2013 with biopsy-proven label of PCNSL. Imaging and staging results were reviewed to exclude secondary/metastatic disease.

Results 20 patients were identified; median age of 58 and 60% were male. Top three clinical presentations were cognitive, paresis and ataxia. Median duration of symptoms was 21 days (range 3 to 180) and median time to biopsy was 14 days.

Pre-biopsy 5 patients had negative CSF, 20% had steroids with documented clinical reason, 5% had record of HIV status checked and 88% had CT staging.

Conclusion Despite limitations, this audit identified that the majority of these patients received steroids pre-biopsy, but in some cases, this may have reasonably been withheld. There is scope for a diagnostic algorithm to highlight safe withholding of steroids, early HIV testing and appropriate staging investigations, downplaying the importance of CSF sampling.