A case of non-lacrimal immunoglobulin G4 (IgG4)-related orbital disease with mastitis.

IgG4-related orbital disease is a recognised cause for orbital inflammation. As its awareness increases and diagnostic accuracy improves there will be an increased number of cases being identified. This unique case demonstrates for the first time, with histological evidence, a case of a non-lacrimal IgG4-related orbital disease with concurrent IgG4-related mastitis.