A reappraisal of the diagnostic and therapeutic management of uncommon histologies of primary ocular adnexal lymphoma

Lymphoma is the most common malignancy arising in the ocular adnexa, whichincludes conjunctiva, lachrymal gland, lachrymal sac, eyelids, orbit soft tissue,and extraocular muscles. Ocular adnexal lymphoma (OAL) accounts for 1%-2% ofnon-Hodgkin lymphoma and 5%-15% of extranodal lymphoma. Histology, stage, andprimary localizations are the most important variables influencing the naturalhistory and therapeutic outcome of these malignancies. Among the various lymphomavariants that could arise in the ocular adnexa, marginal zone B-cell lymphoma(OA-MZL) is the most common one. Other types of lymphoma arise much more rarelyin these anatomical sites; follicular lymphoma is the second most frequenthistology, followed by diffuse large B-cell lymphoma and mantle cell lymphoma.Additional lymphoma entities, like T-cell/natural killer cell lymphomas andBurkitt lymphoma, only occasionally involve orbital structures. Because they are so rare, related literature mostly consists of anecdotal cases included withinseries focused on OA-MZL and sporadic case reports. This bias hampers a globalapproach to clinical and molecular properties of these types of lymphoma, with a low level of evidence supporting therapeutic options. This review covers theprevalence, clinical presentation, behavior, and histological and molecularfeatures of uncommon forms of primary OAL and provides practical recommendations for therapeutic management.