Ocular Adnexal Lymphoma: Clinical Presentation, Diagnosis, Treatment and Prognosis

Ocular adnexal lymphoma (OAL) is a rare tumor with an incidence of 0.2 per 1,00,000 individuals. However, it constitutes the most common orbital tumor especially in older population with an incidence ranging from 11% to 24%. OAL can involve conjunctiva, orbital soft tissues, eyelid, or adnexal structures such as lacrimal gland and lacrimal drainage system. The most common primary OAL is low-grade malignant extranodal marginal zone B-cell lymphoma (EMZL) of mucosa-associated lymphoid tissue (MALT) type. Though various classification and staging systems have been proposed for OAL, currently, American joint committee on cancer (AJCC) TNM (tumor node metastasis) staging is most commonly used. Most commonly, conjunctival lymphoma typically presents as ‘salmon-colored patch’ and orbital lymphoma presents as proptosis, which on imaging shows characteristic appearance of molding around the globe without any globe indentation or bone erosion. Orbital radiotherapy and systemic chemotherapy forms the mainstay of treatment. Newer treatment modalities include immunotherapy with interferon and anti-CD20 antibody rituximab that have been shown to be useful either when used alone or in combination with chemotherapy or as radio-immunotherapy.