P1157 - A Rare Case of Isolated Immunoglobulin G4-related Cholecystitis Mimicking Gallbladder Cancer in an Asymptomatic Patient

Xixi Xu, MD, MS¹, Neal D. Dharmadhikari, MD², Osman Yilmaz, MD³, David P. Nunes, MD^1
1Boston Medical Center, Boston, MA; ²Boston Medical Center, Brookline, MA; ³Boston University School of Medicine, Boston, MA

Introduction: Immunoglobulin G4 related disease (IgG4-RD) is a newly recognized and uncommon fibroinflammatory condition that may involve multiple organs. The most well-recognized manifestation of IgG4-RD is autoimmune pancreatitis (AIP). This report describes a rare case of isolated IgG4-relate cholecystitis without IgG4-related sclerosing cholangitis (ISC) or AIP in an asymptomatic patient.

Case Description/Methods: A 67-year-old male without significant medical history was found incidentally to have significantly elevated alkaline phosphatase level (ALK) and gamma-glutamyl transferase (GGT) level without any symptoms. The patient also had an elevated serum IgG4 level. MRCP showed diffuse circumferential thickening and hyperenhancement of the gallbladder wall. There were prominent, thickened hyper-enhancing folds in the gallbladder neck and fundus. The findings raised the concern for chronic cholecystitis. However, a gallbladder neoplasm cannot be excluded. ERCP showed choledocholithiasis with no features of sclerosing cholangitis. For diagnostic and treatment purpose, cholecystectomy with resection of liver segments IV and V were performed. Histopathological examination revealed diffuse dense plasma cell-rich mononuclear inflammation with scattered eosinophils extending from the subepithelium into the underlying hepatic bed with associated dense fibrosis, lymphoid follicles, and obliterative phlebitis. No histological signs of malignancy were detected. Immunohistochemical staining for IgG4 showed > 40% IgG4/IgG plasma cell ratio. The histological findings were highly suggestive of IgG4-related cholecystitis.

Discussion: The IgG4-related disease is a systemic inflammatory syndrome characterized by extensive infiltration of IgG4-positive plasma cells and lymphocytes with fibrosis and obliterative phlebitis. IgG4-RD is male predominant, and patients are usually older than 50 years of age. IgG4-related cholecystitis generally accompanies ISC or AIP, and cases of isolated IgG4-related cholecystitis are very rare. Elevated serum IgG4 level is a non-specific test for IgG4-RD with the sensitivity and specificity of 50% and 75%, respectively. Although the radiological characteristic of IgG4-related cholecystitis usually shows marked circumferential thickening of the gallbladder wall, it is still challenging to differentiate IgG4-related cholecystitis from gallbladder carcinoma with only radiological findings and elevated serum IgG4 levels. Thus a histopathological diagnosis is necessary to confirm the diagnosis.


Figure: Pathological findings on Magnetic resonance cholangiopancreatography (MRCP). A. MRCP shows prominent thickened hyper-enhancing folds in the gallbladder neck and fundus with the normal pancreas (red arrow). B. diffuse circumferential thickening and hyperenhancement of the gallbladder wall, which measures up to 9 mm in thickness. Multiple gallstones are seen within the gallbladder (red arrow).

Test	Result	Reference
Bilirubin, Total	0.8 mg/dL	0.2-1.2 mg/dL
Bilirubin, Direct	0.3 mg/dL	< or = 0.2 mg/dL
ALK	490 U/L	40-115 U/L
ALT	52 U/L	9-46 U/L
AST	49 U/L	10-35 U/L
GGT	557 U/L	3-70 U/L
IgG	2,417 mg/dL	700-1,600 mg/dL
IgG 4 Subclass	642.0 mg/dL	4.0-86.0 mg/dL
AMA	Negative	Negative

Table: Laboratory test results on initial presentation
ALK: Alkaline phosphatase, ALT: Alanine transaminase, AST: Aspartate transaminase, GGT: Gamma-glutamyl transferase, IgG: Immunoglobulin, AMAs: Antimitochondral antibodies


Disclosures:
Xixi Xu indicated no relevant financial relationships.
Neal Dharmadhikari indicated no relevant financial relationships.
Osman Yilmaz indicated no relevant financial relationships.
David Nunes indicated no relevant financial relationships.


Xixi Xu, MD, MS¹, Neal D. Dharmadhikari, MD², Osman Yilmaz, MD³, David P. Nunes, MD¹. P1157 - A Rare Case of Isolated Immunoglobulin G4-related Cholecystitis Mimicking Gallbladder Cancer in an Asymptomatic Patient, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.