Primary ocular adnexal MALT lymphoma involving the upper eyelid in a young woman: a case report and literature review

Primary ocular adnexal MALT lymphoma (POAML) is a rare indolent small B-cell lymphoma that primarily involves the orbit, conjunctiva, and lacrimal gland, with a high risk of early misdiagnosis. Herein, we report a rare case of POAML arising in the right upper eyelid of a 35-year-old woman, who presented with progressive eyelid swelling. The diagnosis was established by surgical excision, histopathological examination, and immunoglobulin gene rearrangement analysis. No systemic involvement was identified, and the disease was staged as Ann Arbor IE. The patient received local radiotherapy (28 Gy) and achieved complete remission, remaining disease-free during a 3.5-year follow-up. Literature review indicates that POAML predominantly affects middle-aged and elderly individuals, although younger age and female predominance have been reported in Asian populations. Clinical manifestations vary by site and include orbital mass, proptosis, globe displacement, and ocular motility restriction. Conjunctival lesions typically present as hyperemia, chemosis, or a characteristic “salmon-pink” appearance. Histologically, POAML is characterized by diffuse proliferation of centrocyte-like cells, follicular colonization, and lymphoepithelial lesions (LELs), with CD20 and CD79a positivity. Previous studies have identified recurrent molecular alterations in POAML, including changes affecting the BCR/NF-κB, epigenetic, and NOTCH signaling pathways; rearrangements of MALT1 , BIRC3 , BCL10 , and FOXP1 ; and chromosomal abnormalities such as trisomy 3 and trisomy 18. Chronic antigenic stimulation associated with infection or autoimmune disease is considered a major predisposing factor. Treatment is stage-dependent, with surgery, radiotherapy, or observation for early-stage disease and immunochemotherapy for advanced disease. This case underscores that POAML should be considered in the differential diagnosis of progressive eyelid swelling, even in young women, as timely and accurate diagnosis and appropriate treatment can lead to a favorable prognosis.