Immunoglobulin G4-related disease with recurrent uveitis and kidney tumor mimicking childhood polyarteritis nodosa: a rare case report.

Introduction: Immunoglobulin G4-related disease (IgG4-RD) is an condition rarely reported in children. Additionally, IgG4-RD may rarely mimic vasculitis in adults and may infrequently present with uveitis. In our service, 6,198 patients were followed-up and only one (0.0001%) of them had IgG4-RD. To our knowledge, the present IgG4-RD case was the first mimicking childhood polyarteritis nodosa (c-PAN) with recurrent uveitis and kidney tumor.
Case Report: We describe herein a 7-year-old boy that presented intermittent fever. He developed arthralgia, weight loss, myalgia, skin lesions and recurrent uveitis. Skin biopsy revealed necrotizing vasculitis in medium/small sized vessels associated with septal panniculitis suggesting cPAN. Prednisone and azathioprine were administered with improvement. At 11 years, he had persistent fever and abdominal angiotomography revealed a large tumor in left kidney and he was then submitted to nephrectomy. The renal histopathology showed lymphoplasmacytic and histiocytic proliferation with extensive areas of fibrosis, and lymphomonocitic phlebitis with presence of IgG4 in 43 plasmocyte cells, suggesting IgG4-RD.
Discussion: we present herein a unique case of a male pediatric patient with IgG4-RD with rare ocular, cutaneous and renal manifestations.