Difficulty Achieving a Preoperative Diagnosis of IgG4-Related Sclerosing Cholangitis

Area of Science:

• Gastroenterology and Hepatology
• Immunology
• Pathology

Background:

• Bile duct stenosis can present with varied etiologies, including malignancy and autoimmune conditions.
• Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is an increasingly recognized cause of biliary strictures.
• Accurate preoperative diagnosis is crucial for appropriate management of bile duct stenosis.

Observation:

• A 75-year-old male presented with perihilar and distal bile duct stenosis, initially suspected as adenocarcinoma based on imaging and cytology.
• Preoperative evaluation, including imaging and tumor markers, did not reveal elevated IgG4 levels or clear pancreatic involvement.
• Despite initial suspicion of malignancy, surgical specimens showed characteristic histopathological features of IgG4-SC.

Findings:

• Histopathological examination revealed lymphoplasmacytic infiltration, storiform fibrosis, and obliterative phlebitis in the bile ducts and pancreas.
• Immunohistochemistry confirmed diffuse infiltration of IgG4-positive plasma cells, leading to a final diagnosis of IgG4-SC with autoimmune pancreatitis.
• The case underscores the diagnostic difficulty of IgG4-SC when serum IgG4 levels are normal and pancreatic lesions are not apparent.

Implications:

• This case emphasizes the critical role of histopathological analysis in diagnosing IgG4-SC, particularly in atypical presentations.
• It highlights the potential for misdiagnosis of IgG4-SC as malignancy when relying solely on serological markers and initial imaging.
• Understanding these diagnostic challenges is vital for improving patient outcomes and guiding treatment strategies for IgG4-related diseases.