**4.5 Histology**

Histology is a definitive diagnosis. Unfortunately, in the everyday clinical practice, the access to an adequately evaluable biopsy sample is not easy. Characteristic

#### **Figure 4.**

*(a) Nephritis in IgG4-related, type 1. AIP, concurrent with pancreatitis. Arrow: involved renal areas. (b) Primary sclerosing cholangitis like simultaneous extra- and intrahepatic biliary tract lesions. Arrows: bile duct strictures. Pointed arrow: pancreatic duct stricture.*

#### **Figure 5.**

*ERCP of a patient. (a) Long stricture of pancreatic duct in the head (arrow), with a moderate upstream dilatation in the body and tail. (b) Bile duct stricture in the same patient (arrow).*

**99**

*Autoimmune Pancreatitis: Clinical Presentation and Therapy*

histology is easily seen in a surgically resected pancreas [25]. However, this is too late for the patient, who could have been treated safely with steroids instead of a major surgery. Percutaneous pancreatic biopsy made by interventional radiologists has some risks and not a currently used method. Endosonography (EUS)-guided biopsy would be the recommended way to obtain pancreatic tissue. EUS image itself is even somewhat superior to MR and gives valuable information in the differential diagnosis. In addition, fine-needle aspiration by EUS is the safest way to obtain pancreatic cytology. However, cytology has a good performance in the diagnosis of pancreatic cancer but not in the diagnosis of AIP, this latter requiring a real tissue

*ERCP of another patient. (a) Multiple stenotic segments in the bile duct: a long stricture is observed in the distal half of choledochus (arrow) and a shorter stenosis in the hepatic hilum (pointed arrow). (b) Stent* 

*4.5.1 When to perform EUS and FNA? Value of cytology and biopsy in differential* 

Diagnosis of type 1 AIP can be made with high certainty in many patients: clinical symptoms, characteristic images supported by elevated serum IgG4 level, and other organ involvement can assure the diagnosis without pancreatic histology. However, in the absence of these latter conditions, establishing the definitive diagnosis of even type 1 AIP can be difficult. In type 2 AIP, IgG4 is practically never increased, and IBD is the only associated pathology, but only probable diagnosis can be done without histology. With the availability of new biopsy needles (shark, core biopsy), which permit to obtain a small tissue cylinder, diagnostic performance of pancreatic biopsy has dramatically increased, without major risk of complications: clinically significant hemorrhage and pancreatitis are rare, below 1%. Thus, biopsy should be considered in every patient with a suspicion of seronegative type 1 and in

type 2 AIP, preferably before initiating a relatively long steroid treatment.

The improvement in the pancreatic morphology in response to steroid treatment is very quick, easily detectable already after 2 weeks. This fact can be used even in the differential diagnosis: while AIP improves rapidly, pancreatic cancer evidently does not respond to steroids, and no change in the pancreatic morphology can be observed after 2 weeks. In addition, it was demonstrated by Moon et al. [29] that the "lost" 2 weeks did not change the resectability of the malignant lesion. This short treatment trial is only acceptable if a good biopsy is not available or the histologic finding is uncertain in a patient of high surgical risk. It means that steroid

**4.6 Response to glucocorticosteroid treatment**

treatment trial has to be restricted to the cases, when:

*DOI: http://dx.doi.org/10.5772/intechopen.83349*

sample biopsy [26–28].

*(arrow) placement in the bile duct.*

*diagnoses.*

**Figure 6.**

#### **Figure 6.**

*Chronic Autoimmune Epithelitis - Sjogren's Syndrome and Other Autoimmune Diseases...*

In fact, Chari's group published the same tendency from Mayo Clinic [24].

the diagnosis, but cannot be considered as a definitive proof.

**4.4 Other organ involvement**

**4.5 Histology**

**Figure 4.**

patients, later on only in some exceptional cases when even concomitant sclerosing cholangitis was not excluded, and it was impossible to avoid biliary stent placement.

A type 1 AIP is a systemic disease; we can see frequently signs of the disease in other organs. Fibroinflammatory tumor-like pathology of lacrimal and salivary glands is clearly visible, palpable, and easy to access for a biopsy. However, other manifestations, as frequent bilateral nephritis, can be asymptomatic but easily detectable on the MR image (**Figure 4a**), frequently synchronic with the pancreatic disease. Peritoneal fibrosis and aortitis can occur in different times, before or later, as compared to AIP. In our experience PSC like cholangitis and bilateral multifocal nephritis were the most frequent extrapancreatic manifestations, found in 8 and 11 of our 44 type 1 patients, respectively [18]. Any of these manifestations, in particular when their histology confirms IgG4-related disease, can be considered as a definitive proof for type 1 AIP. For type 2, the association of IBD makes probable

Histology is a definitive diagnosis. Unfortunately, in the everyday clinical practice, the access to an adequately evaluable biopsy sample is not easy. Characteristic

*(a) Nephritis in IgG4-related, type 1. AIP, concurrent with pancreatitis. Arrow: involved renal areas. (b) Primary sclerosing cholangitis like simultaneous extra- and intrahepatic biliary tract lesions. Arrows: bile* 

*ERCP of a patient. (a) Long stricture of pancreatic duct in the head (arrow), with a moderate upstream* 

*dilatation in the body and tail. (b) Bile duct stricture in the same patient (arrow).*

*duct strictures. Pointed arrow: pancreatic duct stricture.*

**98**

**Figure 5.**

*ERCP of another patient. (a) Multiple stenotic segments in the bile duct: a long stricture is observed in the distal half of choledochus (arrow) and a shorter stenosis in the hepatic hilum (pointed arrow). (b) Stent (arrow) placement in the bile duct.*

histology is easily seen in a surgically resected pancreas [25]. However, this is too late for the patient, who could have been treated safely with steroids instead of a major surgery. Percutaneous pancreatic biopsy made by interventional radiologists has some risks and not a currently used method. Endosonography (EUS)-guided biopsy would be the recommended way to obtain pancreatic tissue. EUS image itself is even somewhat superior to MR and gives valuable information in the differential diagnosis. In addition, fine-needle aspiration by EUS is the safest way to obtain pancreatic cytology. However, cytology has a good performance in the diagnosis of pancreatic cancer but not in the diagnosis of AIP, this latter requiring a real tissue sample biopsy [26–28].
