Lymphoproliferative Tumors of the Ocular Adnexa

The ocular adnexa include the eyelids, conjunctiva, lacrimal apparatus, and orbital soft tissue. One percent of all lymphomas and approximately 8% of all extranodal lymphomas arise in the ocular adnexa and their incidence is increasing. Reactive lymphoid hyperplasia comprises 16% of all lymphoproliferative tumors of the ocular adnexa. The relative frequencies of ocular adnexal lymphoma presentation are in the orbit, 37%; conjunctiva, 29%; lacrimal apparatus, 20%; and eyelid, 14%. The most frequent primary lymphoma types of the ocular adnexa are extranodal marginal zone lymphoma, 62%; follicular lymphoma, 17%; and diffuse large B-cell lymphoma, 10%. The eyelids show the highest proportion of secondary lymphoma involvement, 49% of all eyelid lymphoproliferative lesions, compared with 24% in all ocular adnexa. The specific aspects of the site, histologic, immunohistochemical, cytogenetic, and molecular findings of the most relevant lymphoma types occurring in the various parts of the ocular adnexa will be discussed in relation to clinical parameters and relevance for therapy choice. Furthermore, the implications of the updated version of the World Health Organization Classification of Tumours of Haematopoietic and Lymphoid Tissues in relation to ocular adnexal lymphoma are reviewed.