Hajime Anjiki

Differentiation of autoimmune pancreatitis from pancreatic cancer by diffusion-weighted MRI.

OBJECTIVES:We sought to clarify the clinical utility of diffusion-weighted magnetic resonance imaging (DWI) for differentiating autoimmune pancreatitis (AIP) from pancreatic cancer.METHODS:Thirteen AIP patients underwent DWI before therapy, and six of them underwent DWI after steroid therapy. The extent and shape of high-intensity areas were compared with those of 40 pancreatic cancer patients. Apparent diffusion coefficient (ADC) values were calculated in the AIP area before and after steroid therapy in pancreatic cancer patients and in a normal pancreatic body.RESULTS:On DWI, AIP and pancreatic cancer were detected as high-signal intensity areas. The high-intensity areas were diffuse (n=4), solitary (n=6), and multiple (n=3) in AIP patients, but all pancreatic cancer patients showed solitary areas (P<0.001). A nodular shape was significantly more frequent in pancreatic cancer, and a longitudinal shape was more frequently found in AIP (P=0.005). ADC values were significantly lower in AIP (1.012±0.112 × 10−3u2009mm2/s) than in pancreatic cancer (1.249±0.113 × 10−3u2009mm2/s) and normal pancreas (1.491±0.162 × 10−3u2009mm2/s) (P<0.001). Receiver operating characteristic analysis yielded an optimal ADC cutoff value of 1.075 × 10−3u2009mm2/s to distinguish AIP from pancreatic cancer. After steroid therapy, high-intensity areas on DWI disappeared or were markedly decreased, and the ADC values of the reduced pancreatic lesions increased almost to the values of normal pancreas.CONCLUSIONS:DWI is useful for detecting AIP and for evaluating the effect of steroid therapy. ADC values were significantly lower in AIP than in pancreatic cancer. An ADC cutoff value may be useful for distinguishing AIP from pancreatic cancer.

Serum IgG4 concentrations and IgG4-related sclerosing disease

BACKGROUNDnBased on histological and immunohistochemical examinations of various organs of patients with autoimmune pancreatitis (AIP), a new clinicopathological entity, IgG4-related systemic disease, was proposed. This study aimed to clarify clinical utility of serum IgG4 levels in differentiating AIP from other pancreatobiliary diseases, clinical utility of serum IgG4 levels in differentiating Mikuliczs disease from other salivary gland disorders, as well as in identifying other IgG4-related diseases.nnnMETHODSnSerum IgG4 levels were measured in 468 patients.nnnRESULTSnThe median serum IgG4 level was significantly greater in AIP (301.5mg/dl) than in other pancreatobiliary diseases (p<0.01). Using the cutoff value of 119 mg/dl that was determined on the basis of this studys ROC curve data, the sensitivity and specificity to distinguish AIP from pancreatic cancer were 82.1% and 94.8%, respectively. The median serum IgG4 level was significantly greater in Mikuliczs disease (357.0mg/dl) than in other salivary gland diseases (p<0.01). Of 75 patients with elevated serum IgG4 levels, 15 had diseases other than pancreatobiliary and salivary gland diseases.nnnCONCLUSIONSnSerum IgG4 levels were useful for diagnosing AIP and Mikuliczs disease. Some diseases with serum IgG4 level elevations may be lesions of IgG4-related systemic disease without manifestations of AIP and Mikuliczs disease.

Endoscopic approach for diagnosing autoimmune pancreatitis

It is of utmost importance to differentiate autoimmune pancreatitis (AIP) from pancreatic cancer (PC). Segmental AIP cases are sometimes difficult to differentiate from PC. On endoscopic retrograde cholangiopancreatography, long or skipped irregular narrowing of the main pancreatic duct (MPD), less upstream dilatation of the distal MPD, side branches derived from the narrowed portion of the MPD, absence of obstruction of the MPD, and stenosis of the intrahepatic bile duct suggest AIP rather than PC. Abundant infiltration of IgG4-positive plasma cells is frequently and rather specifically detected in the major duodenal papilla of AIP patients. IgG4-immunostaining of biopsy specimens obtained from the major duodenal papilla is useful for supporting a diagnosis of AIP with pancreatic head involvement. On endoscopic ultrasonography (EUS), hyperechoic spots in the hypoechoic mass and the duct-penetrating sign suggest AIP rather than PC. EUS and intraductal ultrasonography sometimes show wall thickening of the common bile duct even in the segment in which abnormalities are not clearly observed with cholangiography in AIP patients. EUS-guided fine needle aspiration, especially EUS-guided Tru-Cut biopsy, is useful to diagnose AIP, as well as to exclude PC.

Rapid disappearance of a pancreatic cyst after steroid therapy in a patient with autoimmune pancreatitis.

d t c t p s 66-year-old man was seen at another hospital because of asymptomatic liver dysfunction. He had no history of cute pancreatitis. Although his serum aspartate aminotranserase (114 IU/L; normal, 12–32 IU/L), alanine aminotransferse (238 IU/L; normal, 7– 43 IU/L), and alkaline phosphatase 2127 IU/L; normal, 115–359 IU/L) levels were increased, his erum amylase level (110 IU/L; normal, 39 –115 IU/L) and A19-9 level (10 U/mL; normal, 37 U/mL) were within noral limits. On ultrasound, a 4.5-cm–sized mass was seen in the ancreatic head, and there was a cyst in the pancreatic body. he patient was referred to our hospital for further examinaion. On computed tomography, pancreatic head swelling with elayed enhancement and a 5-cm–sized cyst in the pancreatic ail was found (Figure A). Magnetic resonance cholangiopanreatography showed stenosis of the main pancreatic duct of he head accompanied by mild upstream dilatation of the main ancreatic duct, the cystic lesion in the pancreatic tail, and tenosis of the lower bile duct (Figure B). On endoscopic ret-