IgG4-related sclerosing cholangitis: not always an obvious entity

Area of Science:

• Hepatology
• Gastroenterology
• Immunology

Background:

• Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is a fibrotic inflammatory condition affecting the biliary system.
• It is increasingly recognized as a biliary manifestation of the multi-organ IgG4-related disease (IgG4-RD).
• Accurate diagnosis is crucial as IgG4-SC responds to steroid therapy, unlike malignant conditions.

Observation:

• A case of type 3 IgG4-SC is presented in a patient initially suspected of having cholangiocarcinoma.
• The patient exhibited normal serum levels of Immunoglobulin G4.
• Surgical intervention was performed under the pre-operative diagnosis of malignancy.

Findings:

• The case demonstrates that IgG4-SC can present atypically, mimicking biliary malignancy.
• Normal serum IgG4 levels do not exclude the diagnosis of IgG4-SC.
• Histopathological examination is essential for definitive diagnosis.

Implications:

• This case underscores the diagnostic challenges in distinguishing IgG4-SC from cholangiocarcinoma, particularly in cases with normal IgG4 serum levels.
• It highlights the importance of considering IgG4-SC in the differential diagnosis of biliary strictures, even without elevated IgG4.
• Accurate differentiation is critical for appropriate patient management and treatment selection, avoiding unnecessary aggressive therapies.