Lymphoproliferative lesions of the lacrimal gland: clinicopathological, immunohistochemical and molecular genetic analysis.

BACKGROUND: Lacrimal gland lymphoproliferative disorders are usually classified as orbital adnexal tumours. Because the lacrimal gland is the only orbital structure with native lymphocytes, we examined cases with primary involvement of the gland.

METHODS: The 14 cases were selected from a review of all cases in the surgical pathology files of the Ottawa Hospital between 1992 and 2003. The lesions were categorized according to the latest World Health Organization classification of tumours of lymphoid tissues. We conducted a clinical, histopathological, immunohistochemical, immunophenotypic and molecular genetic analysis of the cases.

RESULTS: The 8 female and 6 male patients, aged 20 to 88 (mean 60) years, were followed for an average of 4 years (range 11 months to 13 years). All presented with supratemporal orbital swelling. The 5 primary lymphomas, of mucosa-associated lymphoid tissue (MALT), were confined to the lacrimal gland (stage IE); 1 tumour transformed to diffuse large B-cell lymphoma, necessitating chemotherapy, and the other 4 were treated with radiation. One of the 5 patients had previously had Sjögren's syndrome. The 6 secondary lymphomas (4 follicular) presented either concurrently with systemic lymphoma or up to 12 years afterwards and were treated in a variety of ways; all the patients had an orbital relapse. At the last follow-up assessment, 6 of the patients with lymphoma had no evidence of disease, 3 were alive with disease, 2 had died (1 of lymphoma, the other with no evidence of disease), and the status of 1 patient was not known. Of the 3 patients with reactive proliferations, 2 had reactive lymphoid hyperplasia (associated with Sjögren's syndrome in 1), and 1 had Rosai-Dorfman disease. All 9 lymphomas that underwent molecular genetic analysis were of B-cell lineage, and 8 had a monoclonal rearrangement in the immunoglobulin heavy-chain gene (IgH); the 9th lymphoma showed an oligoclonal rearrangement. One lymphoma showed the t(14;18) translocation, typical of follicular lymphoma; no lymphoma showed the t(11;18) translocation, commonly found in MALT lymphoma (but only 2 cases were studied). Molecular genetic analysis was performed in 2 of the cases of reactive lymphoid hyperplasia: monoclonal IgH rearrangement was detected in 1 case (the patient with Sjögren's syndrome), oligoclonal rearrangement in the other.

INTERPRETATION: Lacrimal gland lymphomas are B-cell tumours that develop in older adults. Primary tumours, a hIgH proportion of which have MALT characteristics, have a favourable prognosis. Molecular genetic studies may be useful when morphologic and immunophenotypic studies give equivocal results.