Clinical Report: Delays in Diagnosis and Treatment of Primary CNS Lymphoma

Overview

Primary central nervous system lymphoma (PCNSL) is a rare, aggressive extranodal non-Hodgkin lymphoma confined to the CNS, with diagnosis relying on stereotactic biopsy. Delays in diagnosis and treatment significantly impact prognosis, with median survival times improving with timely high-dose methotrexate therapy. Imaging and clinical features guide suspicion, but histopathology remains the diagnostic gold standard.

Background

PCNSL comprises less than 1% of lymphomas and 4% of brain tumors, predominantly affecting older adults with a median age of 65 years. It presents with neurological symptoms depending on lesion location, including cognitive changes, focal deficits, and seizures. Prognosis is poor without treatment, with median survival of 1.5 months, but improves with chemotherapy. Diagnosis requires differentiation from secondary CNS lymphoma and relies on MRI characteristics and histopathological confirmation via stereotactic biopsy.

Data Highlights

Key Findings

• PCNSL is most commonly primary large B-cell lymphoma of the CNS, often presenting as solitary or multiple sharply demarcated lesions on MRI with characteristic imaging features including diffusion restriction.
• Diagnosis requires histopathological confirmation via stereotactic brain biopsy, which has a diagnostic yield exceeding 91%.
• Secondary CNS lymphoma must be excluded through systemic imaging, preferably PET-CT, to avoid unnecessary brain biopsy and treatment delays.
• Prognostic factors include age, performance status, serum LDH, CSF protein levels, and involvement of deep brain structures, though some models lack external validation.
• High-dose methotrexate-based chemotherapy is the cornerstone of treatment, significantly improving survival compared to untreated disease.
• Delays in diagnosis and treatment initiation adversely affect outcomes, emphasizing the need for rapid interdisciplinary evaluation and management.

Clinical Implications

Clinicians should maintain a high index of suspicion for PCNSL in elderly patients presenting with focal neurological symptoms and characteristic MRI findings. Prompt stereotactic biopsy is essential for diagnosis, and systemic evaluation should be performed to exclude secondary CNS involvement. Early initiation of high-dose methotrexate therapy can improve survival outcomes, underscoring the importance of minimizing diagnostic and treatment delays.

Conclusion

PCNSL is a rare but aggressive CNS lymphoma requiring timely diagnosis via stereotactic biopsy and prompt initiation of chemotherapy to improve survival. Awareness of clinical, imaging, and prognostic factors can aid neurosurgeons and multidisciplinary teams in optimizing patient outcomes.

References

1. WHO Classification of CNS Tumours 5th Edition -- CNS Lymphoma Classification
2. Population-Based Studies -- Incidence and Survival Data
3. Memorial Sloan Kettering Cancer Centre Prognostic Model -- Prognostic Factors
4. International Extranodal Lymphoma Study Group -- Prognostic Parameters
5. Recent Clinical Trials -- Survival Outcomes with Treatment
6. Diagnostic Yield of Stereotactic Biopsy -- Histopathological Confirmation