Immunoglobulin G4-Related Ophthalmic Disease Involving the Sclera Misdiagnosed as Intraocular Tumor: Report of One Case.

AIMS Immunoglobulin G4 (IgG4)-related disease is known to have diverse clinical manifestations. We report a case of IgG4-related ophthalmic disease misdiagnosed as intraocular tumor. METHODS Case report. RESULTS A 41-year-old man was referred to our department with a diagnosis of intraocular tumor, presumably choroidal melanoma. Although MR imaging was compatible with choroidal melanoma, he had been observed periodically without treatment because fundus findings were not typical of melanoma and visual function was preserved. He was again referred to us 15 years later due to increased tumor size and visual field disturbance. Transscleral biopsy of the intraocular tumor was attempted to make a histopathological diagnosis. During the biopsy procedure, thick placoid tissue adhering to the sclera was found at a location consistent with the site of the elevated intraocular lesion. Histopathological examination of this extraocular material revealed proliferation of dense fibrous tissue with follicular proliferation of lymphocytes and plasmacytes. The plasmacytes were diffusely positive for IgG and IgG4. Serum IgG4 level was slightly elevated and no extraocular lesion was detected. Despite administration of systemic corticosteroids after biopsy, the intraocular mass was not reduced. Visual acuity of 20/20 has been maintained as of the last follow-up. CONCLUSION IgG4-related disease should be included in the differential diagnosis of intraocular elevated lesion.