Successful "medical" orbital decompression with adjunctive rituximab for severe visual loss in IgG4-related orbital inflammatory disease with orbital myositis.

IgG4-related disease (IgG4-RD) is an inflammatory condition of unknown etiology that can cause tumefactive lesions in a number of tissues and organs, including the orbit and ocular adnexa. Diagnostic criteria for IgG4-RD, including pathology and clinical features and pathology, have been recently proposed. This study presents the first case of unilateral acute visual loss secondary to IgG4-related orbital inflammatory disease with orbital myositis that was complicated by severe compressive optic neuropathy. After initial treatment with pulsed intravenous methylprednisolone, followed by rituximab and radiotherapy, there was a marked improvement in orbital inflammation and clinical and radiological improvement in the compressive optic neuropathy. After 9 months of follow up, the orbital inflammatory disease remained in remission.