# Molecular analysis of bilateral T-cell vitreoretinal lymphoma

## TL;DR

A 63-year-old woman was diagnosed with rare bilateral T-cell vitreoretinal lymphoma using molecular techniques after conventional methods failed.

## Contribution

Demonstrates the critical role of molecular methods in diagnosing rare T-cell vitreoretinal lymphoma cases.

## Key findings

- PCR and NGS identified T-cell receptor clonality and mutations in DNMT3A and MAP2K1.
- Flow cytometry showed peripheral blood and vitreous T-cell immunophenotype similarity.
- Molecular techniques confirmed a rare bilateral T-cell lymphoma diagnosis.

## Abstract

A 63-year-old female who presented with bilateral panuveitis suspicious for a neoplastic etiology, underwent diagnostic pars plana vitrectomy of her right eye. Cytology was negative and flow cytometry did not reveal evidence of B-cell lymphoma. PCR revealed T-cell Receptor Gamma (TRG) clonal peaks and NGS demonstrated mutations in the DNMT3A and MAP2K1 genes. Systemic oncologic surveillance was inconclusive, but flow cytometry of peripheral blood revealed an expansion of aberrant T-cells. Subsequent vitreous biopsy of the fellow eye revealed identical TRG clonal peaks, and T-cell flow cytometry immunophenotype results were similar to those in peripheral blood, with a TRBC1 monotypic pattern, consistent with a diagnosis of bilateral T-cell vitreoretinal lymphoma. T-cell vitreoretinal lymphomas present a diagnostic challenge, which can often delay treatment. This case highlights the usefulness of molecular techniques, such as PCR, flow cytometry and NGS, to complement conventional diagnostic techniques.