A New Location For Pediatric Immunoglobulin G4 Related Disease: The Biceps Muscle

Background. Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a systemic disorder of unknown etiology characterized by elevated serum IgG4 and tissue infiltration of IgG4-positive plasma cells. The disease was described in the pancreas, aorta, thyroid, salivary glands, periorbital tissues, kidneys, pericardium and lymph nodes.Case. Here in, we report a first pediatric case report of IgG4-related disease who presented with a mass in skeletal muscle i.e., biceps muscle.Conclusion. To the best of our knowledge, the involvement in skeletal muscle has previously not been reported in children.