Hemorrhagic Attitude in Frameless and Frame-Based Stereotactic Biopsy for Deep-Seated Primary Central Nervous System Lymphomas in Immunocompetent Patients: A Multicentric Analysis of the Last Twenty Years.

BACKGROUND: Primary central nervous system lymphoma (PCNSL) is a rare manifestation of aggressive extranodal non-Hodgkin lymphoma. In patients with deep-seated lesions, stereotactic brain biopsy (SBB) is an accepted diagnostic procedure to obtain histopathologic confirmation. OBJECTIVE: The aim of this study was to assess the feasibility, diagnostic yield, safety, and complications of stereotactic procedures in midline and deep-seated PCNSLs. METHODS: Patients selected had received a histopathologic diagnosis of PCNSL localized in deep-seated midline structures, obtained by SBB. The intraoperative frozen section was executed as an integral part of the procedure. Computed tomography scan was performed after surgery. RESULTS: A total of 476 SBBs were performed between January 2000 and December 2019 . Of these SBBs, 91 deep-seated lesions had a histologic diagnosis of PCNSL. A significant increase of the incidence of PCNSL compared with all other diseases was observed (P < 0.0001). Eight patients (8.7%) showed a symptomatic hemorrhage, 4 of whom required craniotomy. There were 4 deaths and 2 cases of permanent morbidity. The hemorrhage risk in the PCNSL group was statistically significant (P = 0.0003) compared with other histotypes. CONCLUSIONS: In suspected cases of PCNSL, a histopathologic diagnosis is necessary to distinguish it from glioblastoma or other, nonmalignant conditions. Deep-seated PCNSLs present a higher risk of biopsy-related morbidity and mortality. Intraoperative frozen section increases the diagnostic yield and reduces the number of sampling procedures. Postoperative computed tomography seems to be warranted in patients with suspected PCNSL.