Lymphoproliferative disorders of the ocular adnexa.

Immunodysregulation appears to play a prominent role in the evolution of some lymphomas, as evidenced by the strong associations between congenital and acquired immunodeficiencies and lymphoid neoplasia, and abnormal ratios of helper T cells in lymphoid proliferations. Lympho-proliferative diseases of the ocular adnexa encompass a spectrum of lesions that may present with similar clinical and radiological features. Most primary lymphoid proliferations of the ocular adnexa consist of small lymphocytes of B-cell origin. Employing morphological, immunohistochemical, and molecular genetic criteria, proliferations may be separated into polyclonal and monoclonal categories. Increased insight into the biology and behavior of these tumors tells us that seemingly benign, as well as frankly malignant proliferations, might disseminate to nodal or extranodal sites. The diagnosis of lymphoproliferative disease of any type necessitates a complete workup for systemic lymphoma. Major prognostic criteria for lymphomas are anatomical site, stage, and histological features. Radiotherapy is employed for localized lymphoid proliferations, with chemotherapy recommended for disseminated disease. Long-term follow-up with semiannual examination is recommended. A significant percentage of primary ocular adnexal lymphoid lesions are MALT-type lymphomas, extranodal low-grade B-cell lymphomas usually associated with mucosal tissues or glandular epithelia. The pathogenesis of this lymphoma in orbital soft tissue, which normally is devoid of lymphoid tissue, lymphatic vessels, and epithelium, is unclear. MALT-type lymphomas of the ocular adnexa follow an indolent course, with long periods between relapses, and are responsive to therapy. Dissemination, when it occurs, preferentially affects other extranodal sites.