Lymphoproliferative disorders of the orbit: an immunological approach to diagnosis and pathogenesis.

A prospective immunological study of patients with proptosis due to intraorbital lesions composed largely or exclusively of lymphoid tissue indicates that the use of antisera to specific heavy and light chain antibody components can be helpful in distinguishing between polyclonal and truly neoplastic monoclonal disorders. On the basis of combined histological and immunological information it is possible to delineate 4 categories of patient: those with unequivocal chronic inflammation, those with a virtually pure lymphoproliferative lesion and a polyclonal profile, and those with a monoclonal lymphomatous disorder which may be histologically comparable to the previous category or, in a fourth group, be unmistakably malignant on cytological grounds. The first of these groups will normally respond to corticosteroid treatment, but the others, including the polyclonal lymphoproliferative masses, need radiotherapy. The finding of reduced numbers of circulating T cells in the presence of low plasma levels of IgA, and of autoantibodies in the serum of a third of the patients, could mean that individuals developing lymphoproliferative lesions in the orbit, whether hyperplastic or neoplastic, are partially immunodeficient.