Clinical manifestations
This painless gland enlargement is classic in IgG4-RD involving salivary glands.
sialadenitis
This pattern of fibrosis resembles a woven mat and is characteristic of IgG4-RD.
storiform fibrosis
This autoimmune disease is commonly confused with IgG4-RD due to salivary gland involvement
Sjögren’s syndrome
First-line treatment for IgG4-RD.
glucocorticoids
This lab value is often elevated but not required for diagnosis.
serum IgG4 level
This pancreatic condition is a hallmark manifestation of IgG4-RD.
autoimmune pancreatitis
This vascular finding refers to veins being obliterated by inflammation.
obliterative phlebitis
This malignancy must always be ruled out in pancreatic involvement of IgG4-RD.
pancreatic adenocarcinoma
This monoclonal antibody targets CD20 and is used in refractory disease.
rituximab
This imaging modality is commonly used to evaluate organ involvement like pancreas or retroperitoneum.
CT scan
This retroperitoneal condition can cause ureteral obstruction in IgG4-RD.
retroperitoneal fibrosis
This type of inflammatory infiltrate is rich in plasma cells
lymphoplasmacytic infiltrate
Unlike IgG4-RD, this condition shows monoclonal lymphocyte proliferation on biopsy.
lymphoma
This newer monoclonal antibody targets CD19 and depletes a broader range of B-lineage cells, including plasmablasts, and is emerging as a potential therapy in refractory IgG4-RD.This is the typical response of IgG4-RD to steroids.
inebilizumab
A patient has classic imaging and elevated serum IgG4, but diagnosis remains uncertain. This remains the gold standard to confirm IgG4-RD.
tissue biopsy
This orbital manifestation often presents with proptosis or swelling.
Idiopathic orbital inflammation
An absolute count above this number of IgG4+ plasma cells per high-power field (HPF) supports diagnosis (organ-dependent but commonly cited threshold).
5x the ULN
This vasculitis type is a mimicker on histopathology for IgG4-RD.
granulomatosis with polyangiitis (GPA)
A patient with newly diagnosed IgG4-RD with mild submandibular gland swelling and no organ-threatening disease presents. Best initial therapy?
Glucocorticoids
In IgG4-RD, this combination of histologic features (the “classic triad”) supports the diagnosis.
storiform fibrosis, obliterative phlebitis, and lymphoplasmacytic infiltrate
This vascular involvement can lead to aneurysm formation in IgG4-RD
Aortitis
What pathological findings are not seen in IgG4-RD? (5)
Necrosis, neutrophils, granulomatous inflammation Multinucleate giant cells, histiocytes
This vasculitis can mimic IgG4-RD with orbital disease, sinus involvement, and mass-like lesions, but is distinguished by ANCA positivity and necrotizing granulomas.
granulomatosis with polyangiitis (GPA)
A patient with suspected IgG4-RD has classic imaging findings and elevated serum IgG4, but malignancy has not been excluded. Best next step before starting treatment?
obtain a tissue biopsy
This biopsy feature helps distinguish IgG4-RD from Sjögren’s syndrome.
absence of significant lymphoepithelial lesions