# Diagnostic Odyssey: Primary CNS Lymphoma (Lymphoma Cerebri) Presenting as Rapidly Progressive Dementia

## TL;DR

A rare brain cancer called primary CNS lymphoma can mimic dementia and be difficult to diagnose, especially after prior immunosuppressive treatment.

## Contribution

This paper presents a case where PCNSL was successfully treated after a long diagnostic delay due to atypical presentation.

## Key findings

- PCNSL can present as rapidly progressive dementia, complicating diagnosis.
- Prior immunosuppressive therapy for autoimmune conditions can mask PCNSL symptoms.
- Successful treatment of PCNSL is possible even after a prolonged diagnostic delay.

## Abstract

Primary central nervous system lymphoma (PCNSL) is a rare brain cancer that sometimes presented as rapidly progressive dementia. Diagnosing PCNSL presenting with rapidly progressive neurocognitive symptoms can be challenging, especially when the patient was previously treated with immunosuppressants for suspected autoimmune processes. We present a case where PCNLS was eventually and successfully treated 18 months after neurological symptoms started.