Immunoglobulin G4-related orbital disease: report of two pediatric cases.

IgG4-related disease is a systemic fibro-inflammatory disorder mainly affecting the middle-aged and elderly population. IgG4-related orbital disease is very rare in childhood. We present here two children with IgG4-related orbital disease, one of whom responded well to prednisolone treatment while the other one was refractory to most immunosuppressive agents. It is important to treat patients at the early active stage of disease before fibrotic changes predominate. Thus, although rare, increased awareness of IgG4-related orbital disease in childhood may avoid delays in diagnosis and treatment.