Ocular adnexal lymphoma. A clinicopathologic study with identification of lymphomas of mucosa-associated lymphoid tissue type.

PURPOSE: Extranodal marginal zone B-cell lymphoma (low-grade B-cell lymphoma of mucosa-associated lymphoid tissue [MALT] type) is a distinctive type of lymphoma that usually arises in association with mucosa or other epithelial structures and has an indolent clinical course. The frequency and clinical features of MALT lymphomas in the ocular adnexa have not been well studied.

METHODS: The authors examined the clinicopathologic features of ocular adnexal lymphoma, identified a subset of cases with MALT characteristics, and determined patient outcome.

RESULTS: The 42 patients, 16 men and 26 women age 35-89 years (mean, 64) were followed an average of 4.8 years. Thirty-two patients had ocular adnexal involvement at presentation (primary ocular adnexal lymphoma) and 10 had a history of lymphoma that relapsed in the orbit (secondary ocular adnexal lymphoma). In the primary group, 23 patients had lymphoma confined to the ocular adnexa, 3 had a single lesion that invaded adjacent structures, and 6 had distant spread at the time of presentation. Twenty-five patients achieved a complete remission. Nine patients, including 6 patients whose disease was localized initially, had progression or relapse of disease in distant sites. At last follow-up, 21 patients were free of disease, 9 were alive with disease and 2 had died of lymphoma. In the secondary group, at last follow-up, 1 patient had died of other causes, free of lymphoma, 3 patients were alive with disease and 5 had died of lymphoma (outcome not known in 1 case). Using the recently described revised European-American lymphoma classification, we found 16 MALT lymphomas, 8 diffuse large B cell, 12 follicular center, 3 mantle cell, 1 B-small lymphocytic lymphoma, and 2 unclassifiable low-grade lymphomas. The most common type of primary lymphoma was MALT type (15 of 30 classifiable cases), and the most common secondary lymphoma was follicular center (6 of 10). No increased frequency of conjunctival or lacrimal gland involvement by MALT lymphomas was found. All 33 lymphomas with immunophenotyping were of B lineage.

CONCLUSIONS: Ocular adnexal lymphomas are B-cell tumors that develop in older adults, predominantly among women. Primary orbital lymphomas have a favorable prognosis; a high proportion of them have MALT characteristics.