Feasibility of 5-aminolevulenic acid fluorescence for diagnostic guidance in intracranial lymphoma surgery: A case series and systematic review of 170 patients.

[BACKGROUND] Intracranial lymphomas are rare tumors of the central nervous system, predominantly affecting elderly patients. While 5-aminolevulinic acid (5-ALA) fluorescence is well established in glioma surgery, its diagnostic role in intracranial lymphoma remains unclear, particularly regarding the effect of corticosteroid use. This study evaluated the diagnostic performance of 5-ALA-guided biopsy and its relationship with corticosteroid exposure.

[METHODS] We conducted a retrospective case series and a systematic review. Adult patients who underwent stereotactic or open biopsy with 5-ALA guidance for radiologically suspected intracranial lymphoma at Gachon University Gil Medical Center (2022-2025) were analyzed. A comprehensive literature search (MEDLINE, EMBASE, Web of Science, Cochrane Library) through May 2025 identified studies reporting 5-ALA use in intracranial lymphoma biopsy. Diagnostic yield, fluorescence patterns, and corticosteroid effects were assessed.

[RESULTS] Five patients were included in the institutional series: strong fluorescence was observed in four and vague in one, with an overall positive predictive value of 80 %. Across 18 studies (170 patients), 5-ALA fluorescence was detected in 77.6 %, with 78 % pooled sensitivity and 22 % false-negative rate. Among 12 patients with documented corticosteroid use, discontinuation ≥7 days before biopsy correlated with higher fluorescence positivity, though not consistently with diagnostic success.

[CONCLUSIONS] 5-ALA fluorescence serves as a useful adjunct for intracranial lymphoma biopsy, enhancing sampling efficiency and procedural safety. However, fluorescence alone cannot ensure diagnostic adequacy, and frozen section confirmation remains necessary. Corticosteroid use does not uniformly suppress fluorescence but may influence diagnostic reliability.