暂无摘要。

BACKGROUND: IgG4-related cholecystitis, which is a manifestation of IgG4-related disease in the gallbladder, is associated with autoimmune pancreatitis or IgG4-related sclerosing cholangitis in most cases; isolated gallbladder lesions without systemic manifestations are very rare. Gallbladder wall thickening is often diffuse, but sometimes localized, in which case, differentiation from gallbladder cancer becomes difficult. The characteristic features of IgG4-related cholecystitis on imaging that would enable differentiation from gallbladder cancer remain poorly described.
METHODS: We present a rare case of isolated IgG4-related cholecystitis with localized gallbladder wall thickening that was clinically difficult to distinguish from malignancy before resection. An 82-year-old man was referred to our hospital because of gallbladder wall thickening on abdominal ultrasonography without any symptoms. Dynamic computed tomography of the abdomen showed localized wall thickening from the body to the fundus of the gallbladder that was enhanced from an early stage with a prolonged contrast effect. There were no other findings, such as pancreatic enlargement and bile duct dilatation. Magnetic resonance cholangiopancreatography revealed neither dilatation nor stenosis of the bile duct and pancreatic duct. Endoscopic ultrasonography (EUS) showed a smooth layered thickening of the gallbladder wall with a maximum thickness of 6 mm and a well-preserved outermost hyperechoic layer in the same area. Laparoscopic cholecystectomy was performed because malignancy could not be completely ruled out. Pathological examination of a resected specimen revealed IgG4-positive plasma cell infiltration, fibrosis, and phlebitis. Although the serum IgG4 level measured after resection was normal, the condition was ultimately diagnosed as probable IgG4-related cholecystitis according to the 2020 revised comprehensive diagnostic criteria for IgG4-related disease. The EUS images reflected the pathological findings, in which lymphocytic infiltration was distributed in a laminar fashion in the gallbladder wall.
CONCLUSIONS: Although rare, isolated IgG4-related cholecystitis with localized wall thickening mimicking gallbladder cancer remains a clinical problem. A smooth laminar thickening of the gallbladder wall on EUS imaging could be one of the most informative characteristics for differentiating IgG4-related cholecystitis from gallbladder cancer.

UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: 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.

Immunoglobulin G4 (IgG4)-related disease is a multi-organ immune-mediated condition that can mimic many inflammatory, malignant, and infectious disorders. Isolated IgG4-related cholecystitis without systemic manifestation is extremely rare. We report a rare case of IgG4-related disease with its clinical, radiological and histopathological findings involving only the gallbladder which presented initially as unresectable locally advanced gallbladder cancer on imaging but was diagnosed as IgG4-related cholecystitis preoperatively depending upon serum IgG4 levels and immunohistochemistry. Patient was successfully treated with steroids followed by simple cholecystectomy in view of symptomatic gallstones. Preoperative diagnosis is challenging for IgG4-related cholecystitis in view of mass like appearance of the lesion with surrounding invasion on imaging so most of the cases are reported postoperatively. Knowledge of this disease as differential for malignancy can save patients from extensive resections in view of its steroid responsive nature. Xanthogranulomatous cholecystitis mimicking gallbladder cancer can coexist with this disease.

Objective: IgG4-related sclerosing cholecystitis is generally associated with IgG4-related sclerosing cholangitis and presents with diffuse, circumferential thickening of the gallbladder wall. We report a rare case of localized IgG4-related sclerosing cholecystitis without IgG4-related sclerosing cholangitis, which was difficult to differentiate from gallbladder cancer preoperatively. Patient: A 56-year-old man with suspected IgG4-related disease or gallbladder cancer was admitted to our ward. The serum IgG4 level was elevated at 721 mg/dL. Computed tomography (CT) demonstrated focal wall thickening of the gallbladder fundus. Drip infusion cholecystocholangiography with CT revealed no dilation, stenosis, or border irregularity of the bile duct. Results: For diagnostic and treatment purposes, cholecystectomy with wedge resection of the gallbladder bed was performed. The pathological diagnosis was IgG4-related sclerosing cholecystitis. Conclusion: It is difficult to differentiate IgG4-related sclerosing cholecystitis from gallbladder cancer in cases involving localized thickening of the gallbladder wall. In similar cases, surgical resection with cancer in mind might be performed based on present clinical knowledge.

Immunoglobulin G4 (IgG4)-related sclerosing disease is a systemic inflammatory syndrome, and an understanding of its characteristics is currently evolving. IgG4-related cholecystitis is a manifestation of IgG4-related sclerosing disease in the gallbladder. This case report describes the clinical, radiographic, and histopathological findings in a young male patient who presented with a synchronous mass in the gallbladder. Serum levels of IgG4 and the IgG4/IgG ratio were normal, and there was no associated autoimmune pancreatitis. Therefore, establishing a preoperative diagnosis of IgG4-related cholecystitis was very difficult, and a differential diagnosis of gallbladder cancer infiltrating the liver was suggested. Postoperative histopathological examination established a diagnosis of IgG4-related cholecystitis definitively. A preoperative diagnosis of IgG4-related cholecystitis, although possible, would have been highly challenging in this case. It is difficult to establish whether surgical intervention is necessary in IgG4-related cholecystitis. Because malignant tumors are frequently suspected with this clinical presentation, surgical intervention should be undertaken only after due deliberation.