Disease related to IgG4. Apropos of two cases

Abstract

The disease related to IgG4 (ER-IgG4 in Spanish) is a multi-systemic, autoimmune disease characterized by inflammatory fibro-sclerotizing lesions forming masses or pseudo tumors, high concentrations of serum IgG4 and extensive tissue infiltrations by IgG4-positive plasma cells. It includes several entities previously considered organ-specific ones. It can affect almost any organ, being pancreas, salivary glands, lacrimal glands, lymphatic ganglion, retroperineum and kidneys the most affected ones. The diagnosis is made through combining clinical, serologic, imaging and histopathological findings. It has a reserved prognosis but with an early diagnosis its control is reached, and occasionally also the disease’s remission, although it tends to have relapses. It is an underdiagnosed disease, partially due to its recent characterization. We present two cases entering the range covered by this disease, the Riedel’s thyroiditis and retroperitoneal fibrosis, both initially answering to therapy with high doses of corticoids after diagnosis.