J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website https://www.jocmr.org

Review

Volume 13, Number 2, February 2021, pages 75-81

Isolated Type Immunoglobulin G4 Sclerosing Cholangitis: The Misdiagnosed Cholangiocarcinoma

Figure 1. The different types of IgG4-SC with the differential diagnosis. Arrows indicate sites of strictures/stenosis. IgG4-SC: immunoglobulin G4 scelrosing cholangitis.

**Table 1.** The HISTORt Criteria for the Diagnosis of IgG4-SC
Diagnostic criterion	Description
IgG4-SC: immunoglobulin G4 scelrosing cholangitis; HPF; high-power field; AIP: autoimmune pancreatitis.
Histology of bile duct	There is lymphoplasmacytic sclerosing cholangitis on resection specimens (lymphoplasmacytic infiltrate with > 10 IgG4-positive cells per HPF within and around bile ducts with associated obliterative phlebitis and storiform fibrosis). Bile duct biopsy specimens often do not provide sufficient tissue for a definitive diagnosis; however, presence of > 10 IgG4-positive cells per HPF (in the biopsy specimen) is suggestive of IgG4-SC.
Imaging of bile duct	There are one or more strictures involving intra-hepatic, proximal extra-hepatic, or intra-hepatic bile ducts. There are fleeting/migrating biliary strictures.
Serology	There is an increase in serum IgG4 level (normal: 8 - 140 mg/dL).
Other organ involvement	Pancreas: there are classic features of AIP on imaging or histology (diffusely enlarged pancreas with delayed enhancement and capsule-like rim). Suggestive imaging findings include focal pancreatic mass/enlargement without pancreatic duct dilation, multiple pancreatic masses, focal pancreatic duct stricture without upstream dilation and pancreatic atrophy. There is retroperitoneal fibrosis. Renal lesions: there are single or multiple parenchymal low-attenuation lesions (round, wedge shaped or diffuse patchy). There is salivary/lacrimal gland enlargement.
Response to steroid therapy	There is normalization of liver enzymes or resolution of stricture (although complete resolution of stricture may not be seen early in the course of treatment or in patients with predominantly fibrotic strictures).

Table 1. The HISTORt Criteria for the Diagnosis of IgG4-SC

Diagnostic criterion

Description

IgG4-SC: immunoglobulin G4 scelrosing cholangitis; HPF; high-power field; AIP: autoimmune pancreatitis.

Histology of bile duct

There is lymphoplasmacytic sclerosing cholangitis on resection specimens (lymphoplasmacytic infiltrate with > 10 IgG4-positive cells per HPF within and around bile ducts with associated obliterative phlebitis and storiform fibrosis). Bile duct biopsy specimens often do not provide sufficient tissue for a definitive diagnosis; however, presence of > 10 IgG4-positive cells per HPF (in the biopsy specimen) is suggestive of IgG4-SC.

Imaging of bile duct

There are one or more strictures involving intra-hepatic, proximal extra-hepatic, or intra-hepatic bile ducts. There are fleeting/migrating biliary strictures.

Serology

There is an increase in serum IgG4 level (normal: 8 - 140 mg/dL).

Other organ involvement

Pancreas: there are classic features of AIP on imaging or histology (diffusely enlarged pancreas with delayed enhancement and capsule-like rim).
Suggestive imaging findings include focal pancreatic mass/enlargement without pancreatic duct dilation, multiple pancreatic masses, focal pancreatic duct stricture without upstream dilation and pancreatic atrophy.
There is retroperitoneal fibrosis.
Renal lesions: there are single or multiple parenchymal low-attenuation lesions (round, wedge shaped or diffuse patchy).
There is salivary/lacrimal gland enlargement.

Response to steroid therapy

There is normalization of liver enzymes or resolution of stricture (although complete resolution of stricture may not be seen early in the course of treatment or in patients with predominantly fibrotic strictures).

**Table 2.** Clinical Differences Between IgG4-SC and Cholangiocarcinoma
	IgG4-SC	Cholangiocarcinoma
IgG4-SC: immunoglobulin G4 scelrosing cholangitis; M: male; F: female; IgG4: immunoglobulin G4.
Age	Middle age to elderly	Middle age to elderly
Sex	M > F	M > F
Clinical presentation	Jaundice and weight loss	Painless jaundice
Elevated IgG4 levels	70-90%	13.5-22%

Table 2. Clinical Differences Between IgG4-SC and Cholangiocarcinoma

IgG4-SC

Cholangiocarcinoma

IgG4-SC: immunoglobulin G4 scelrosing cholangitis; M: male; F: female; IgG4: immunoglobulin G4.

Age

Middle age to elderly

Sex

M > F

Clinical presentation

Jaundice and weight loss

Painless jaundice

Elevated IgG4 levels

70-90%

13.5-22%