Aqueous humor may offer a novel screening option for vitreoretinal lymphoma

With evidence that a key vitreoretinal lymphoma (VRL) mutation can be detected in aqueous humor, aqueous-humor screening could provide a less invasive alternative to vitreous biopsy for diagnosing and monitoring VRL.

Study design

This was a retrospective chart review of 21 eyes (17 patients) diagnosed with vitreoretinal lymphoma (VRL) who underwent evaluation for the presence of MYD88 L265P mutation in aqueous humor at the Kellogg Eye Center at the University of Michigan between January 2020 and April 2022. All patients were diagnosed by cytopathologic analysis of a vitreous sample, with additional molecular testing for B-cell clonality and MYD88 L265P mutation when possible. Eighteen eyes (14 patients) had biopsy-confirmed or clinically diagnosed VRL, and 3 eyes (3 patients) had biopsy-confirmed vitritis. Some patients with known systemic and central nervous system diffuse large B-cell lymphomas (DLBCLs) were diagnosed clinically because of poor systemic condition. Approximately 0.2 mL of aqueous humor was collected from each patient before treatment either at the time of vitreous biopsy or at the initial office visit using a 30-gauge needle inserted through the temporal limbus. Aqueous humor was recollected 4–6 weeks after completing intravitreal injection therapies of methotrexate and rituximab. Cellular and cell-free DNA was extracted using centrifugation and the Quick-DNA urine kit and evaluated for the presence of the L265P mutation in the MYD88 gene using an allele-specific, real-time PCR assay.

Outcomes

Aqueous humor–derived MYD88 L265P mutation was detected in 15 (83%) of the 18 eyes with VRL but was not identified in any of the 3 eyes with vitritis. The mutation was less readily detectable in cellular DNA (10 of 18 eyes) compared with cell-free DNA (15 of 18 eyes). Aqueous sampling after combined intravitreal methotrexate and rituximab injection therapy revealed no clinical evidence of VRL recurrences or detectable aqueous humor–derived MYD88 L265P mutation in the 7 eyes that achieved complete response 9 months after treatment. The mutation was detected in 1 eye that developed recurrence 6 months after treatment.

Limitations

The main limitations of this study are the relatively small number of cases, specifically those with biopsy-proven diagnoses, and the short follow-up period. The control group is also very small, limiting its reliability. In addition, the use of the MYD88 L265P mutation alone without including other tumor-specific alterations may limit the sensitivity of detection of VRL based on mutation prevalence.

Clinical significance

This study suggests that aqueous humor-derived cell-free MYD88 L265P mutation can be detected in eyes with VRL. As a result, aqueous-humor testing may serve as a potential surrogate, less invasive diagnostic option for vitreoretinal lymphoma, especially in individuals in whom vitreous biopsy is not feasible. It may also be a valuable tool for the surveillance of a patient's response to treatment.

Financial Disclosures: Dr. Maya Eiger-Moscovich discloses no financial relationships.