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PCNSL – HD-MTX — SCE Neurology MCQ

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HardNeuro-oncologyPCNSL – HD-MTXSCE Neurology

An immunocompetent adult has a deeply situated, homogeneously enhancing periventricular mass. CSF is non-diagnostic and systemic staging shows no extracranial lymphoma. Primary CNS lymphoma is suspected and corticosteroids are not clinically essential before diagnosis. What is the preferred diagnostic and treatment pathway?

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Correct answer: E — Stereotactic biopsy followed by high-dose methotrexate treatment

The best answer is “Stereotactic biopsy followed by high-dose methotrexate treatment”. PCNSL is diffusely infiltrative and highly chemosensitive; stereotactic tissue diagnosis is preferred, corticosteroids can cause radiological and histological disappearance, and induction commonly centres on high-dose methotrexate rather than routine resection. “Attempt gross total resection as routine curative treatment” is less appropriate because deep infiltrative disease is not usually cured by resection and surgery adds neurological risk “Give corticosteroids for several weeks before any tissue sampling” is less appropriate because pre-biopsy steroids can make the biopsy non-diagnostic unless urgent mass-effect treatment is required “Use whole-brain radiotherapy alone as universal first-line treatment” is less appropriate because radiotherapy alone has important neurotoxicity and is not the universal modern induction strategy “Observe before full assessment because homogeneous enhancement proves lymphoma” is less appropriate because imaging is suggestive but not specific enough to omit histology

Reference: NICE NG99: Brain tumours and brain metastases in adults. https://www.nice.org.uk/guidance/ng99/chapter/Recommendations