IgG4-related disease (IgG4-RD) may involve one or more organs.
Hallmarks:
(1) chronic sclerosing fibrosis with lymphoplasmacytic inflammation and storiform fibrosis
(2) inflammatory pseudotumor
Sites of involvement include:
(1) salivary and/or lacrimal glands (Mikulcz'a syndrome, Kuttner tumor of the submandibular gland)
(2) orbital (including pseudotumor)
(3) central nervous system (infundibular hypophysitis, hypertrophic pachymeningitis, intracerebral inflammatory pseudotumor)
(4) autoimmune pancreatitis
(5) sclerosing cholangitis
(6) chronic sclerosing aortitis or inflammatory aortitis with aneurysm
(7) sclerosing thyroiditis (Riedel's struma)
(8) retroperitoneal fibrosis
(9) periarteritis or eosinophilic angiocentric fibrosis
(10) idiopathic cervical fibrosis
(11) pulmonary (interstitial pneumonitis, inflammatory pseudotumor)
(12) lymph node (may overlap with Castleman's disease)
(13) prostate pseudotumor
(14) breast pseudotumor
(15) hepatic pseudotumor
(16) gastrointestinal tract
(17) pericardium and pleura
(18) fibrosing mediastinitis
(19) sclerosing mesenteritis
(20) skin (pseudolymphoma)
(21) renal (tubulointerstitial nephritis, pseudotumor)
A PET scan can identify sites of involvement if systemic disease is suspected.
