Case Report: A Peculiar Pinguecula? A Surprising IgG4-Related Conjunctival Lesion.

Abstract

Introduction: IgG4-related disease (IgG4-RD) is a chronic immune-mediated fibroinflammatory condition that may involve multiple organs but rarely presents as an isolated conjunctival lesion. Ocular surface involvement can mimic benign inflammatory conditions, leading to diagnostic delay. We report a rare case of isolated conjunctival IgG4-RD initially misdiagnosed as recurrent pingueculitis.

Case presentation: A 37-year-old female presented with a gelatinous, cystic mass on the bulbar conjunctiva. Comprehensive ophthalmic examination and anterior segment optical coherence tomography (OCT) revealed a well-demarcated subconjunctival lesion without scleral or intraocular invasion. Differential diagnoses included conjunctival lymphoma, ocular surface squamous neoplasia, and nonspecific orbital inflammation. An excisional biopsy was performed, and histopathological examination confirmed IgG4-RD, demonstrating dense lymphoplasmacytic infiltration with CD138- and IgG4-positive plasma cells, storiform fibrosis, and abundant collagen fibers. Postoperatively, a suspected local recurrence was successfully treated with topical dexamethasone. At 6-month follow-up, complete clinical remission was achieved without additional local or systemic therapy.

Conclusion: This case highlights the importance of considering IgG4-RD in the differential diagnosis of atypical conjunctival lesions. Tissue biopsy remains essential for definitive diagnosis, while adjunctive imaging modalities such as anterior-segment OCT may aid in lesion characterization, even in the absence of systemic disease.