Monomorphic epitheliotropic intestinal T‐cell lymphoma involving the aqueous humour

A 70-year-old woman presented with rapid-onset anterior uveitis in her right eye. Two years earlier, she was diagnosed with monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) on jejunum biopsy. No central nervous system involvement was found at diagnosis. She underwent surgery for tumour resection, followed by six cycles of CHOP chemotherapy, achieving complete remission. On admission, blood work was normal with no circulating lymphoma cells, and 18fluorodeoxyglucose PET/CT showed no abnormal accumulation. Slight flare and cells (3+) were observed under the slit lamp microscope (upper left panel, arrow). An anterior chamber paracentesis was performed. The cytospin preparation of aqueous humour (AH) raised suspicion for lymphomatous involvement, showing monomorphic small- to medium-sized cells with irregular nuclear contours, condensed chromatin and pale cytoplasm containing azurophilic granules (upper central and right panels, May-Grunwald Giemsa, 1000× magnification). Interestingly, the IL10/IL6 ratio in the AH was less than 1, indicating a local inflammatory response; however, it was speculated that this might represent an early stage in the tumour's progression. Flow cytometry of the AH confirmed an aberrant T-cell phenotype: CD3+, CD8+, CD56+, CD103+, TIA1+, exclusively expressing TRBC1+ (bottom panel, red population). No infiltration was detected in the cerebrospinal fluid. Next-generation sequencing revealed mutations in SETD2 (variant allele frequency [VAF] 50%), JAK3 (VAF 39%) and STAT5B (VAF 45%), consistent with the findings from the initial biopsy. Based on these results, intravitreal high-dose methotrexate injections were initiated. This case highlights the aggressive nature of MEITL with atypical intraocular infiltration at relapse, contrasting with the more common pleuro-pulmonary or hepatic extranodal involvement (Veloza L, Cavalieri D, Missiaglia E, Bisig B, Pereira B, Bonnet C, et al. Monomorphic epitheliotropic intestinal T-cell lymphoma comprises morphologic and genomic heterogeneity impacting outcome. Haematologica. 2023;108(1):181–95). The diagnosis remains challenging, necessitating coordination between ophthalmologists and cytologists. Due to their rarity and fragility in the aqueous humour, lymphoma cells are not always identifiable. Therefore, interleukin levels, molecular biology and imaging are combined with clinical examination to support the diagnosis. The authors did not receive support from any organization for the submitted work. This manuscript respects the ethic policy of CHU Lyon for the treatment of human research participants. No patient-identifying data were used. The authors did not obtain written informed consent from the patient, but the patient did not object to his data being used for research purposes (as required by ethic policy of CHU Lyon). The authors declare no use of third-party material in this study for which formal permission is required.