Possible role of chlamydiae in ocular adnexal lymphoma

Abstract

Background: Ocular adnexal lymphomas (OAL) represent malignant lymphoid neoplasms which develop as primary or secondary tumor manifestations in the orbit, conjunctiva, lacrimal gland and eye lid. Some reports suggest that OALs may be an antigen driven disorder, but the source of antigen(s) is not understood. Chlamydia psittaci (Cp) has been linked to the development and maintenance of ocular adnexal marginal zone B-cell lymphoma (OAMZL) in some countries with varying reports but no study was done in Indian population. The present study was designed to detect chlamydial antigen in ocular adnexal lymphomas in Indian patients. Methods: Prospective analysis (2010-2011) of 18 cases of ocular adnexal non-Hodgkin's lymphomas was undertaken. Clinicopathological features were reviewed to confirm the diagnosis of non-Hodgkin's lymphoma. Classification of all the eighteen cases was done according to WHO classification (2001). Immunohistochemical characterization of was performed using commercial monoclonal antibodies CD20, clone L26; CD3, clone LN10; CD5 clone 4C7; CD10, clone 56C6 and mAb Cyclin-D1 antibodies. Immunohistochemical localization of C.trachomatis and C.psittaci antigens was also performed on all the cases using mAb Novus biological, A21.65. Follow up details of 5/18 (28%) patients was available. Results: Of the 18 cases of ocular adnexal non-Hodgkin's lymphomas, 16 cases (89%) were diagnosed as MALT lymphomas and 2 cases were diffuse large B-cell lymphomas (DLBCL). All 16 cases of MALT lymphomas were B-cell type (CD20 positive), while they were negative for CD3, CD5, CD10 and Cyclin-D1. Chlamydial antigen expression for C.trachomatis and C.psittaci was detected in a single case of MALT lymphoma. The tumor was located in the left orbit. No systemic spread was present at the time of diagnosis. Follow-up study did not reveal recurrence at 6 months. Conclusion: MALT lymphomas have been linked with Cp infection in different geographical regions. Bacterial clearance with antibiotic therapy is often followed by lymphoma regression. The association of C.psittaci with MALT lymphoma may necessitate new treatment modalities against MALT lymphomas.