Isolated Immunoglobulin G4-Related Uveitis Diagnosed by Choroidal Biopsy.

This report highlights a rare case of isolated immunoglobulin G4 (IgG4)-related uveitis in a 24-year-old woman, diagnosed by globe-sparing vitrectomy and choroidal biopsy. She presented with treatment-resistant posterior uveitis characterised by a white elevated subretinal lesion, which progressed to panuveitis and scleritis, causing intractable pain and reducing vision to light perception. After extensive investigations failed to identify a cause, a diagnostic vitrectomy with excisional choroidal biopsy was performed. Histological analysis confirmed IgG4-related disease, despite the absence of systemic involvement. This is the first reported case of isolated IgG4-related uveitis diagnosed by vitrectomy, avoiding enucleation. The procedure provided therapeutic benefit, resolving pain and inflammation. This case highlights the importance of considering IgG4-related disease in uveitis with elevated subretinal lesions and demonstrates the value of obtaining a substantial choroidal biopsy via advanced vitrectomy techniques to establish an accurate diagnosis in these rare and challenging cases.