Purpose or Case Report: Immunoglobulin4 related disease (IgG4RD) is an inflammatory condition involving multiple regions of the body resulting in fibrosis which can lead to eventual organ failure. This entity was originally described with autoimmune pancreatitis. Recently many other previously described lesions have been brought under the umbrella of IgG4RD. These include a spectrum of conditions involving the head and neck region (orbits, salivary and lacrimal glands), thyroid gland (Riedel’s thyroiditis), vasculature (periaortitis), kidneys, lungs, retroperitoneum, mesentery, pituitary gland, biliary tract, pericardium, lymph nodes and pachymeninges.
Reports of IgG4RD are quite rare in the pediatric literature, however this may be due to potential unawareness about the condition as well as the variable presentations and non-specific imaging features of IgG4RD. The prevalence in pediatric population is poorly described.
The exact pathophysiology of IgG4RD is yet to be completely elucidated. The imaging manifestations are non-specific, and primarily consist of tumefactive enlargement of involved organs and homogenous contrast enhancement and associated lymphadenopathy. IgG4RD may manifest in single organ or may present as widespread disease involving multiple organs. These features overlap with other mass forming conditions like malignancy or lymphoma. However, the presence of multifocal disease with more than one organ involvement may point towards possible IgG4 related disease. Other than IgG4 related autoimmune pancreatitis, there is no consensus on diagnostic criteria based upon imaging. Definitive diagnosis of IgG4RD is made with biopsy and the histology characterized by infiltration of lymphocytes and IgG4 plasma cells with storiform fibrosis and obliterative phlebitis. According to Boston consensus, the ratio of IgG4 /IgG in tissue should be more than 0.4 with more than 10 IgG4+ cells per high power field. Serum IgG4 levels range from normal to elevated. Steroids are effective as first line treatment in majority of patients.
Our aim in this presentation is to familiarize radiologists with the spectrum of imaging features, and areas of involvement in IgG4 related disease using cases of IgG4RD collected at three different pediatric hospitals. It is important for pediatric radiologists to be familiar with this relatively newly described disease entity and be aware of the spectrum of manifestations of IgG4RD, ensuring prompt recognition and early treatment.
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