Ocular Adnexal Marginal Zone Lymphoma of Mucosa-associated Lymphoid Tissue

Ocular adnexal lymphomas are a group of heterogeneous neoplasms representing approximately 1-2% of non-Hodgkin lymphomas and 8% of extranodal lymphomas. The incidence of primary ocular adnexal lymphoid tumors has raised over the last decades, and this could be probably attributed to the more sophisticated diagnostic techniques. Due to the wide spectrum of clinical manifestations, ocular tissue biopsy is important in order to set a precise diagnosis based on histological, immunophenotypical and, in some cases, molecular findings. The most common subtype, which may account for up to 80% of primary ocular adnexal lymphomas, is extranodal marginal zone lymphoma (EMZL) of mucosa-associated lymphoid tissue. This lymphoma is usually asymptomatic in the early phase of the disease causing a delay in the final diagnosis and prompt therapy. The pathogenesis of a proportion of these tumors has been linked to chronic inflammatory stimulation from specific infectious factors (e.g., Chlamydia psittaci) or to autoimmunity. The further improvement in diagnostic methods and the further understanding of the pathogenesis of ocular adnexal EMZL may contribute to the establishment of a more successful multidisciplinary therapeutic planning.