Ocular Adnexal Marginal Zone Lymphomas (OAMZL): Lack of Evidence for Chlamydia Psittaci (C. Psittaci) Infection in a Clinicopathologic Study from a Single Institution

Ocular adnexal lymphomas (OAL) represent up to 55% of all orbital tumors, being extranodal marginal zone lymphoma (OAMZL) the most frequent histological subtype reported in approximately 50% of patients and its etiology and pathogenesis are still not well understood. There are conflicting reports regarding the association between C. Psittaci infection and ocular adnexal lymphoma (OAMZL), in part because this association may vary between different geographical regions. Herein, we analyzed the clinical features and the presence of C. Psittaci infection in a cohort of 28 patients with OAMZL diagnosed from a single Spanish institution. All tumor samples were centrally reviewed by two pathologists, and C. Psittaci infection was determined in tumor specimens by a Semi-nested PCR method. Between January 1984 and April 2009, 28 patients were diagnosed with primary OAMZL. The median age was 70 years (range: 31- 89) and 40% were male. The great majority of patients (79%) were diagnosed in stage I-extranodal (IE), and six patients (21%) had bilateral ocular involvement. IgH rearrangement was confirmed in 25 out of 28 cases with OAMZL. PCR for C. Psittaci infection was negative in all 28 tumor specimens analyzed. Most patients (82%) were treated with immunochemotherapy combinations, being chlorambucil based regimens the most frequently used. Overall, 18 out of 24 patients (75%) achieved a complete response after first-line treatment. Median PFS was of 79 months (IC 95% 36 - 121). Whereas C. Psittaci infection in OAMZLs has been proved in up to 90% of patients in Northern Italy, in this Spanish cohort OAMZLs were not associated with C. Psittaci infection. These findings confirm that the association between C. Psittacci infection and OAML is highly heterogeneous even between the same geographic regions. In these regions where C. Psittaci infection is not prevalent, the search for alternative antigenic stimuli driving the appearance of this lymphoma is warranted.