Xanthogranulomatous cholecystitis shows overlapping histological features with IgG4-related cholecystitis.

XGCs with IgG4-positive cell infiltration are considered to be mimickers, as xanthogranulomatous inflammation generally contradicts a diagnosis of IgG4-related disease and is weakly associated with other typical organ manifestations of IgG4-related disease. However, XGC may be a concurrent condition, particularly in patients with IgG4-related disease in other organs.