Ocular adnexal lymphoma: a clinicopathologic study of a large cohort of patients with no evidence for an association with Chlamydia psittaci.

Non-Hodgkin lymphomas are among the most common primary tumors occurring in the ocular adnexa. Herein, we present a 14-year single-institution experience in 62 patients with primary ocular adnexal lymphomas (OALs). Association with Chlamydia psittaci infection is examined in 57 tumor specimens. Extranodal marginal zone lymphoma (EMZL) was the most frequent histologic subtype (89%). The majority of patients with EMZL (84%) presented with stage E-extranodal (IE), however only 16% had an advanced stage. All stage IE patients were treated with local radiotherapy, whereas patients with disseminated disease received systemic therapy with or without local irradiation. All but 1 patient with EMZL achieved complete remission (CR). During a median follow-up of 52 months (range, 3-153 months), the estimated 5-year overall survival (OS) and freedom from progression (FFP) were 96% and 79%, respectively. During the follow-up, 22% of patients relapsed, mainly in extranodal sites, and 4% transformed to diffuse large B-cell lymphoma. None of the patients exhibited local orbital failure in the radiation field. None of the OAL specimens harbored C psittaci DNA. Our study demonstrates that EMZLs, accounting for the majority of primary OALs, are characterized by an indolent natural history with frequent, continuous extranodal relapses. In South Florida, OALs are not associated with C psittaci infections.

Expression of the human germinal center-associated lymphoma (HGAL) protein, a new marker of germinal center B-cell derivation.

We identified the human germinal center-associated lymphoma (HGAL) in gene-expression profiling studies of diffuse large B-cell lymphoma (DLBCL). The expression of HGAL correlated with survival in patients with DLBCL. The HGAL gene is the human homolog of M17, a mouse gene expressed specifically in normal germinal center (GC) B cells. We generated a monoclonal antibody against the HGAL protein and show that HGAL is expressed in the cytoplasm of GC lymphocytes and in lymphomas of GC derivation. Among 727 lymphomas tested by immunohistochemistry on tissue microarrays, HGAL staining was found in follicular lymphomas (103 of 107), Burkitt lymphomas (40 of 40), mediastinal large B lymphomas (7 of 8), and in DLBCLs (103 of 151). Most marginal zone lymphomas lacked HGAL staining. Lymphocyte-predominant Hodgkin lymphomas (12 of 17) and, surprisingly, classical Hodgkin lymphomas (78 of 107) were found to be positive. Hierarchical clustering of comparative immunohistologic results in DLBCLs demonstrates that the expression of HGAL is similar to 2 other GC-associated proteins, BCL6 and CD10, but different from 2 markers associated with a non-GC phenotype, MUM1/IRF4 and BCL2. The restricted expression and GC specificity of HGAL protein suggest that it may have an important role in the diagnosis of specific lymphomas, and, potentially in the identification of subtypes associated with different prognoses.