Efficacy of Vitreous Biopsy and Clinical Course in Vitreoretinal Lymphoma: A Single-Center Retrospective Analysis

Background/Objectives: The high risk of CNS dissemination poses a significant challenge in the management of primary vitreoretinal lymphoma (PVRL). We evaluated the clinical value of our institutional protocol for PVRL, which combines targeted vitreous sampling with routine central nervous system (CNS) surveillance using magnetic resonance imaging (MRI) every 4-6 months. Methods: We retrospectively reviewed 34 consecutive patients who underwent vitreous biopsies at Niigata University Hospital between January 2010 and December 2021; 12 patients were initially diagnosed with PVRL without CNS involvement. The protocol mandates submission of both undiluted vitreous samples and the entire vitreous cassette contents, including perfusion fluid, for cytologic evaluation. Patients with PVRL underwent MRI surveillance every 4-6 months. Results: Among 12 patients with PVRL, vitreous cytology classified as Class IV or higher demonstrated a positivity rate of 75% (9/12) using undiluted samples alone, which increased to 92% (11/12) when cassette contents were included. Ancillary test results revealed an interleukin (IL)-10/IL-6 ratio > 1 in 75% (9/12) and immunoglobulin heavy chain gene rearrangement in 92% (11/12). Extraocular relapse occurred in 92% of patients (11/12), including 10 cases of CNS involvement and one systemic relapse, with a mean time to CNS progression of 11.8 months. The 5-year overall survival was 58%. Conclusions: Comprehensive vitreous sampling incorporating perfusion fluid may improve cytologic detection in PVRL within a single-center setting. Routine MRI surveillance facilitates early detection of CNS relapse in patients with PVRL; however, a survival benefit cannot be established from this retrospective analysis.