Eosinophilic fasciitis associated with IgG4-related disease

A 52-year-old male presented with pain and induration of the skin and muscles. Physical examination revealed swelling and induration of the skin and muscles of the arms, forearms, hands, thorax, abdomen, and legs, accompanied by the characteristic orange peel appearance. In addition to bilateral hearing impairment, there was enlargement of both lacrimal glands. Laboratory results revealed hyper-eosinophilia, elevated C-reactive protein, and erythrocyte sedimentation rate, hypocomplementaemia, polyclonal hypergammaglobulinaemia, elevated IgE, IgG, and increased IgG1 and IgG4. MRI of the lower limbs reported enhanced contrast in the muscles of both thighs with thickening of the semimembranosus vastus lateralis fascia and arms. A skin and fascia biopsy indicated lymphoplasmacytic infiltrate, eosinophils, and non-storiform fibrosis. Immunohistochemistry showed IgG4 positivity in less than 10%, with an IgG4/lgG range of less than 40%. The patient meets the criteria for eosinophilic fasciitis and ACR/EULAR criteria for IgG4-RD. For this reason, we would like to report the first case found of eosinophilic fasciitis associated with IgG4-RD.