Lymphoproliferative lesions of the ocular adnexa. Differential diagnostic guidelines

The ocular adnexal lymphomas represent the malignant end of the spectrum of lymphoproliferative lesions which occur in the conjunctiva, eyelids, lacrimal gland and orbit. The new "W.H.O. Classification of Tumours of Haemopoietic and Lymphoid Tissues" is the most suitable for subdividing the ocular adnexal lymphomas, whereby the extranodal marginal zone B-cell lymphoma (EMZL) represents the most common lymphoma subtype. Management of patients with ocular adnexal lymphomas includes a systemic medical examination to establish the clinical stage of the disease. Most patients have stage IE disease and current recommended therapy for this is radiotherapy, while disseminated disease is treated with chemotherapy. Despite usually demonstrating an indolent course, EMZLs are renowned for recurrence in extranodal sites, including other ocular adnexal sites. Furthermore, Blastic transformation of EMZL with a corresponding aggressive clinical course has been described. Long-term follow-up with half-yearly examinations are therefore recommended. Major prognostic criteria for the ocular adnexal lymphomas include the age of the patient, anatomical location of the tumour, stage of the disease at first presentation, serum lactate dehydrogenase level at the time of diagnosis, lymphoma subtype as determined using W.H.O. lymphoma classification and the tumour cell growth rate. The clinical symptoms and histopathological findings of the differential diagnosis of lymphoproliferative lesions of the ocular adnexa are discussed.