Classification and characteristics of IgG4-associated cholangitis
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Classification and characteristics of IgG4-associated cholangitis

Dr. med. Christian Dietrich / Philipp Herberg / Professor Dr. med. Ralf Jakobs

Medizinische Klinik C, Klinikum der Stadt Ludwigshafen

Classification and characteristics of IgG4-associated cholangitis and how to differentiate it from hepatobiliary malignancies — mimicry in hepatobiliary endoscopy

On the basis of a clinical case, typical endoscopic findings and diagnostic criteria for hepatobiliary IgG4 disease are described here, along with the classification of the condition. The guideline of the European specialist association (United European Gastroenterology, UEG) is also discussed.

A 73-year-old male patient with a suspected diagnosis of neoplasia in the pancreaticobiliary system was referred to us with jaundice, B symptoms, and upper abdominal symptoms, following magnetic resonance cholangiopancreatography (MRCP) at an outside center. The laboratory findings from his family physician showed raised liver values suggesting cholestasis (total bilirubin 11.8 mg/dL; ref. < 1.2 mg/dL) and a raised CA19-9 value (150 U/mL; ref. < 37 U/mL).

Fig 1 On radial endoscopic ultrasound the entire pancreas is hypoechoic with inhomogeneous swelling and a hard appearance on elastography blue honeycomb It should be noted that the pancreatic duct is not dilated
Fig 2 EUS radial duplex with an arrow marking the common hepatic duct CHD There is clear thickening of the walls up to 6 mm The bile ducts particularly the extrahepatic CHD show hypoechoic discontinuous and extensive thickening of the walls
Fig 3 Type 2B discontinuous strictures in the intrahepatic and extrahepatic bile ducts

The UEG European guideline [1] proposes a classification into four types, which was originally first presented by Nakazawa et al. [2]. Following extensive biopsy sampling from the biliary duct system, two endoprostheses were introduced here in suprahilar locations on the left and right.

Fig 4 Cholangiographic classification of IgG4 cholangitis based on Nakazawa et al 2 with the frequencies corresponding to the different types 1 Type 1 with distal stenosis of the CHD is the most frequent form In type 2 distal CHD stenosis occurs in combination with segmental type 2a or diffuse type 2b intrahepatic stenoses as in the present case In type 3 there is hilar and distal stenosis of the CHD Type 4 resembles Klatskin tumor

Although the Nakazawa classification is of central importance for the differential diagnosis as a purely morphological description, it is only one of many different factors in the treatment and course of the condition.

Bile duct configurationDifferential diagnosis
Type 1Distal CCC, carcinoma of the pancreatic head, chronic pancreatitis
Types 2a and 2bPrimary or secondary sclerosing cholangitis
Type 3Distal CCC, carcinoma of the pancreatic head with hilar metastases
Type 4Klatskin tumor
Table 1:  Differential diagnosis relative to Nakazawa types

A diagnosis of gastrointestinal manifestations of IgG4 disease is established in the same way as with the other forms of this systemic disease, based on the HISORt criteria [1]: histology, typical imaging findings, serology (which has a high diagnostic value if IgG4 > 4× upper limit of normal), manifestations in several organs, and the response to treatment with steroids.

In the present case, the IgG4 serum level was raised by more than tenfold, and treatment with prednisolone 40 mg was therefore initiated for IgG4 cholangitis in combination with autoimmune pancreatitis.

Fig 5 Cholangiogram after 4 weeks of prednisolone therapy during removal of the endoprostheses right showing complete remission in comparison with the initial findings left This is an important diagnostic criterion
Fig 6 On the EUS check up examination the extensive thickening of the wall has declined from 6 mm to 2 mm The surrounding pancreatic tissue is much less hypoechoic compare Fig 2 Due to the high recurrence rate long term maintenance therapy is usually necessary

References

1. Löhr JM, Beuers U, Vujasinovic M. et al.; UEG guideline working group. European Guideline on IgG4-related digestive disease – UEG and SGF evidence-based recommendations. United European Gastroenterol J. 2020 Jul;8(6):637-666. doi: 10.1177/2050640620934911. Epub 2020 Jun 18. PMID: 32552502; PMCID: PMC7437085.

2. Nakazawa T, Naitoh I, Hayashi K, Miyabe K, Simizu S, Joh T. Diagnosis of IgG4-related sclerosing cholangitis. World J Gastroenterol. 2013;19(43):7661-7670. doi:10.3748/wjg.v19.i43.7661

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