IgG4-Related Disease

Definition & etiology (NEJM 2012;366:539; Ann Rev Pathol 2014;9:315)

  • Characterized by tumor-like inflammatory lesions that can affect nearly any organ
  • Etiology unclear: ? autoimmune; unclear role of IgG4 Ab; Pt may have h/o atopy

Clinical manifestations (Lancet 2015;385:1460; Arth Rheum 2015;67:2466)

  • Commonly pancreatitis, aortitis, cholangitis, sialadenitis, thyroiditis, orbital myositis ± pseudotumor, retroperitoneal fibrosis
  • Multiple lesions may be present synchronously or metachronously

Diagnosis (Ann Rheum Dis 2015;74:1 & 14)

  • Biopsy w/ specific histopathology & immunohistochemistry findings: lymphoplasmacytic infiltrate w/ significant IgG4+ plasma cell infiltrate, fibrosis, obliterative phlebitis
  • ↑ serum (Se 90%, Sp 60%);