Fluorescence in situ hybridization (FISH) analysis of primary ocular adnexal MALT lymphoma

Background: It remains unknown whether primary ocular adnexal extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue ( MALT lymphoma) is a homogeneous entity, as there are few reports of the results of cytogenetic or molecular analyses of these tumors. Methods: We performed interphase fluorescence in situ hybridization ( FISH) analysis to detect translocations and aneuploidy in 34 cases of primary ocular adnexal MALT lymphoma, and reviewed the histopathological findings. Correlations between the results of FISH analysis, the histopathological features and the clinical data were also analyzed. Results: Among the 34 cases, FISH analysis revealed t(14; 18)( q32;q21) in one case, trisomy 3 in 21 cases ( 62%), and trisomy 18 in 16 cases ( 47%). The cases with trisomy 18 had significantly more prominent lymphoepithelial lesions ( LELs) and less nodularity in the tumors. In regard to the clinical correlations, tumors with trisomy 18 were observed predominantly in females and younger patients; also, in the majority of the cases, the tumor was of conjunctival origin. All the cases with recurrence showed trisomy 18 in the tumor. Conclusion: Primary ocular adnexal MALT lymphoma is a significantly heterogeneous entity. Cases with trisomy 18 may have unique clinicopathological features.