Gallbladder wall thickening in patients with IgG4-related diseases, with special emphasis on IgG4-related cholecystitis

Gallbladder (GB) wall thickening sometimes occurs in patients with autoimmune pancreatitis (AIP), a condition for which the name, IgG4-related cholecystitis, was proposed. We examined the radiological findings of the GB in patients with IgG4-related diseases and clinical features of patients with GB wall thickening and presented a hypothesis of its pathogenesis.GB wall thickening was defined by thickness ≥ 4 mm. GB wall thickness was examined in 258 patients with IgG4-related disease. Clinical and imaging findings of 200 patients with AIP with and without GB wall thickening were then compared.GB wall thickening was detected in 58 patients (29%) with AIP and two patients with isolated IgG4-related sclerosing cholangitis. In the 60 GBs examined, wall thickening was diffuse, with the walls possessing a smooth inner surface. No GB wall thickening was detected among the 56 patients with IgG4-related disease without AIP or IgG4-related sclerosing cholangitis. Bile duct stenosis was detected in 56 patients (97%) with AIP with GB wall thickening. Intraductal ultrasonography indicated cystic duct wall thickening connected to bile duct wall thickening in 11 of 14 (79%) patients with AIP or IgG4-related sclerosing cholangitis with GB wall thickening. Forty-eight patients in whom IgG4-related cholecystitis was diagnosed experienced resolution of the GB wall thickening after receiving steroid therapy.Most cases of GB wall thickening in IgG4-related diseases are closely associated with IgG4-related sclerosing cholangitis and may be a manifestation of IgG4-related disease throughout the biliary tract, including the bile duct, cystic duct, and GB.