Hyalinizing cholecystitis with features of immunoglobulin G4-related disease-coincidence or an unrecognized association? A case report.

Hyalinizing cholecystitis (HC) is a recently described rare subtype of chronic cholecystitis characterized by dense, paucicellular collagenous transmural fibrosis, which usually replaces the mucosa and muscularis propria. Immunoglobulin (Ig)G4-associated cholecystitis is also a newly described cholecystitis variant characterized by transmural or extramural lymphoplasmacytic inflammation, lymphoid follicles, storiform fibrosis, phlebitis, and increased tissue IgG4-positive plasma cells. We describe a case of cholecystitis in an elderly white man who harbored features of both HC and IgG4-associated cholecystitis. In retrospect, the patient also had a significantly elevated serum IgG4 level. To the best of our knowledge, an association between HC and IgG4-related disease has not been previously described in the literature. Although not entirely conclusive, our observations raise the possibility that some cases of HC represent the end stage of IgG4-related disease.