Corticosteroid Use Before Stereotactic Brain Biopsy for Suspected Lymphoma.

Background and objectives: Primary central nervous system lymphoma (PCNSL) is a rare, aggressive lymphoma requiring histopathological confirmation for diagnosis. Stereotactic brain biopsy (SBB) is the gold standard for definitive diagnosis, but preoperative corticosteroid therapy (CST), commonly administered to manage symptoms, may induce cytoreduction and obscure diagnostic features. Previous studies offer conflicting evidence on whether CST compromises diagnostic yield. This study assesses the impact of preoperative CST on the diagnostic yield of SBB in PCNSL, evaluating steroid timing, dose, duration, and associated postoperative complications.

Methods: We retrospectively reviewed 725 patients who underwent SBB between 2014 and 2025 to identify 104 patients with pathologically confirmed PCNSL. Patients were categorized based on CST exposure and stratified by timing, cumulative dose, and duration of therapy. Clinical, radiological, and pathological variables were analyzed. Statistical tests included χ2, Welch t-test, and Fisher exact test.

Results: The overall diagnostic yield was 92.3%. Among patients who received CST (n = 43), the diagnostic yield was 95.3% (95% CI: 84.2%-99.4%), compared with 90.2% (95% CI: 79.8%-96.3%) in the non-CST group (P = .46). Yield remained high across intervals between CST administration and biopsy (<48 hours: 96.4%; 48-72 hours: 91.7%; >72 hours: 100%; P = .658), cumulative dose (≤20 mg: 95.5% [95% CI: 78.2%-99.2%], 21-40 mg: 100% [95% CI: 70.1%-100%], >40 mg: 100% [95% CI: 70.1%-100%]; P = 1.0), and duration (≤5 days: 94.6% [95% CI: 81.8%-99.3%] vs >5 days: 100% [95% CI: 91.8%-100%]; P = 1.0). Postoperative complications occurred in 4.8% of cases, with no significant difference by CST status.

Conclusion: Preoperative corticosteroids do not significantly reduce diagnostic accuracy in PCNSL in our cohort. These findings support the safe use of CST for symptom control in suspected PCNSL with expeditious biopsy. Optimizing biopsy timing, technique, and coordination among disciplines remains essential to ensure diagnostic success.