Immunoglobulin G4-Related Disease Manifesting as Posterior Uveitis.

Purpose: To describe an atypical presentation of immunoglobulin G4 (IgG4)-related disease manifesting as posterior uveitis and masquerading as intraocular lymphoma. Methods: A single case was reviewed. Results: A 74-year-old man with a history of a left orbital lesion and prior nondiagnostic biopsies was referred for evaluation of bilateral choroidal lesions suspicious for intraocular lymphoma. Fundus examination revealed irregular hyperpigmentation of the retinal pigment epithelium with a leopard-spot pattern on fundus autofluorescence. Optical coherence tomography showed diffuse choroidal thickening with a "lumpy-bumpy" appearance and an exudative retinal detachment in the right eye. Diagnostic pars plana vitrectomy and subretinal fluid drainage showed negative flow cytometry, cytology, and MYD88 mutation testing. Subsequent enlargement of the left orbital lesion prompted repeat biopsy, which confirmed IgG4-related disease. The patient responded well to prednisone and rituximab. Conclusions: IgG4-related disease may present with atypical posterior uveitis findings and mimic intraocular lymphoma. This entity should be considered in the differential diagnosis of posterior uveitis masquerade syndromes.