Clinical features and outcomes of primary ocular adnexal follicular lymphoma: a retrospective analysis.

Extranodal follicular lymphoma (FL) demonstrates unique clinicopathological features and prognostic implications, and the clinical characteristics of ocular adnexal FL are poorly documented. In this study, we retrospectively analyzed histologically confirmed cases of ocular adnexal FL at our institution between 1997 and 2019. Of the 261 patients with lymphoma involving the ocular adnexa, 28 had FL, and staging revealed that 10 had primary ocular adnexal FL. Of these 10 patients, one was excluded because of insufficient treatment information. The median age of the remaining nine patients (six women) was 62 (range: 24-81) years. Lesions were located in the orbit (three patients) or conjunctiva (six patients). Three patients had bilateral conjunctival lesions. Eight patients were initially treated with radiotherapy (including one who received radiotherapy after 1.5 years of observation); the other patient remained untreated for 6.4 years. With a median follow-up period of 7.7 years, three of eight patients who received radiotherapy relapsed (two in the contralateral conjunctiva, one in the subcutaneous tissue of the back), and no in-field relapses occurred. The 5-year progression-free and overall survival rates were 75% and 100%, respectively, without histological transformation. In conclusion, primary ocular adnexal FL has a favorable prognosis after radiotherapy and/or watchful waiting.