Clinicopathologic analysis of ocular adnexal lymphomas: Extranodal marginal zone B-cell lymphoma constitutes the vast majority of ocular lymphomas among Koreans and affects younger patients

The majority of ocular adnexal lymphomas (OAL) are primary marginal zone B-cell lymphomas (MALT lymphomas). The present study correlated the clinicopathological variables with the histologic subtypes by World Health Organization (WHO) classification with emphasis on MALT lymphomas in OALs of Koreans. There were 68 cases (31 males and 37 females), with a mean age of 45.9 years (range 7-89 years). Histologically, 61 MALT-type, 2 diffuse large B-cell (DLBCL), 2 mantle cell type (MCL), 1 anaplastic large-cell (ALCL), and 2 NK/T-cell lymphomas (NK/T-L) were counted among them. Fifty-seven were primary cases (P-OAL), and 11 were secondary cases (S-OAL). Nearly all P-OALs were MALT lymphomas (n = 56, 98%), with an exception of 1 MCL. Eleven S-OALs included 5 MALT type, 2 DLBCL, 1 ALCL, 1 MCL, and 2 NK/T-L. All MALT lymphoma patients were alive (n = 59) except for 2 after a mean duration of follow-up of 27.6 months (range: 0-108 months): one died of an unrelated cause and one died of recurrence. One non-MALT type P-OAL was alive with no evidence of disease (42 months). Of the 11 S-OAL, 4 had marrow involvement and 5 had progression or relapse outside the orbit. Compared with the other subtypes, MALT lymphoma was more likely to present with local disease (P= 0.001), achieve complete remission (CR) (0.022), and be alive at last follow-up (0.197), and less likely to experience recurrence (P = 0.06). In conclusion, OALs in Koreans are characterized by a preponderance of primary lymphomas over systemic lymphomas, striking predominance of MALT type lymphomas, and young age of occurrence. Histologic subtype by WHO classification has a significant correlation with the final outcome, with the most favorable outcome associated with OALs of the MALT type.