Abstract
Purpose :
To determine the role of single cells molecular analysis from remnant cytology samples for vitreoretinal lymphoma (VRL) diagnosis. Vitreoretinal lymphoma is often difficult to diagnosis due to the paucicellular yield of fragile VRL tumour cells. Single cell molecular analysis may provide further genetic data to aid clinical diagnosis.
Methods :
This study was performed in compliance with the Declaration of Helsinki with informed consent and SingHealth institutional review board approval. A total of 4 patient remnant samples of aqueous/ vitreous fixed in PreservCyt® was obtained from the Singapore General Hospital Department of Anatomical Pathology and Cytology after the diagnosis was confirmed. IgH rearrangement were performed as a part of clinical diagnosis. Two samples were confirmed vitreoretinal large B cell lymphomas and 2 were inflammatory controls. Single B (CD20+/CD3-/CD19+) cells were sorted using DEPArray™ Nxt and were subjected Whole Genome Amplification (WGA) for low-pass genome sequencing with Illumina® platform and copy number alterations (CNA, Figure 1), BCL2 translocation (PCR) and MYD88L265Panalysis. Additional cases (2 vitreous inflammatory controls with treated systemic B cell lymphoma and 1 atypical case) were also analysed for comparison.
Results :
Cytology-proven VRL positive cases (2/2) showed IgH clonality with BCL2 100% major breakpoint translocation, MYD88L265Pmutation and abnormal CNA, in contrast to cytology-negative cases with no prior lymphoma history (2/2) that showed no IgH clonality, no BCL2 breakpoint translocation, normal WT MYD88 and no abnormal CNA. The atypical case suspicious for B cell lymphoma on cytology revealed genomic findings similar to negative cases. In contrast, inflammatory controls from patients with previous history of systemic lymphoma showed no clonality, or BCL2 breakpoint mutations and normal CNA but had mutant MYD88L265P.
Conclusions :
Additional genomic information such as BCL2 breakpoint translocations and CNA are useful to support cytological diagnosis especially when borderline morphology or paucicellular sampling is present. Single cell analysis increases diagnostic potential of paucicellular samples and allows genomic testing such as BCL2 breakpoint translocations and abnormal CNA that are also useful for prognosis.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.