Supplementary Material for: Case report: A peculiar pinguecula? A surprising IgG-4 related conjunctival lesion case report

Abstract Introduction: IgG4-related disease (IgG4-RD) is a systemic fibro-inflammatory condition that can affect various organs. Ocular involvement is common; however, conjunctival lesions as the initial and isolated presentation are rare. This case highlights an unusual manifestation of IgG4-RD, emphasizing its consideration in the differential diagnosis of conjunctival lesions. Case Report: A 37-year-old female presented with a gelatinous, cystic mass on the bulbar conjunctiva of her left eye, initially suspected to be neoplasia. Excisional biopsy revealed subconjunctival infiltration with plasma cells positive for IgG4 staining. The IgG4:IgG ratio was 20%, and storiform fibrosis was observed. Systemic workup was incomplete due to patient preferences. The patient was diagnosed with conjunctival inflammation suggestive of IgG4-RD. Anterior segment optical coherence tomography (ASOCT) helped delineate lesion characteristics. Topical dexamethasone resulted in complete resolution within 6 months. Discussion: This case demonstrates a rare presentation of IgG4-RD as an isolated conjunctival lesion without systemic involvement. It underscores the importance of considering IgG4-RD in the differential diagnosis of conjunctival lesions, even in the absence of other typical manifestations. ASOCT can aid in evaluating these lesions. Conclusion: Isolated conjunctival lesions can be a rare presenting sign of IgG4-RD. Clinicians should maintain a high index of suspicion for IgG4-RD in atypical conjunctival lesions, and biopsy with immunohistochemical staining is crucial for diagnosis.