Hepatitis C virus in MALT-lymphoma of the ocular adnexa

Objective: Hepatitis C virus (HCV) has been proposed as a possible etiologic factor in ocular adnexal marginal zone lymphoma (OAML). We aimed to assess the prevalence of HCV infection in patients with OAML through a systematic review and meta-analysis. Methods: Electronic databases were searched from their inception to August 2019 for studies assessing HCV seroprevalence in patients with OAML. Pooled prevalence of HCV infection was calculated with 95 % confidence interval (CI). Statistical heterogeneity among studies was quantified via the inconsistency index (I2). Funnel plot symmetry was used to assess the risk of bias across studies. Results: Nine studies with 360 patients were included. Overall pooled prevalence of HCV in OAML was 12.7 %, with low statistical heterogeneity (I2 = 17.4 %) and with asymmetrical funnel plot. The studies clustered into two groups: 5 studies (3 from Italy and 2 multicenter with a major Italian contribution) showed a higher HCV prevalence in OAML (15.6 %), while the other 4 (from countries other than Italy) showed a lower prevalence (4.7 %); in both subgroups, statistical heterogeneity was null (I2 = 0%) and funnel plot was symmetrical. Conclusion: HCV might be a significant etiologic factor of OAML in Italy.