Ultrasonographic investigation of cholangiocarcinoma in Lao PDR.

Opisthorchis viverrini is a group 1 carcinogen that causes cholangiocarcinoma (CCA). Although opisthorchiasis is known to be severely endemic to several areas along the Mekong River in Lao PDR, the CCA status of residents of this region is still under investigation. In this study, we analyzed the results of abdominal ultrasonography (US) performed on 6113 residents in 9 provinces (Vientiane Municipality, Savannakhet, Phongsaly, Khammouane, Saravane, Champasak, Vientiane, Xieng Khuouang, and Luang Prabang provinces) of Lao PDR from 2007 to 2011. Overall, 51 cases (0.83%) were detected with suspected CCA. The CCA rates in Vientiane Municipality and in Savannakhet and Khammouane provinces were 1.45%, 1.58%, and 1.09%, respectively. However, in the other 6 provinces, the rate of CCA averaged only 0.26%. In the 3 provinces with higher rates of CCA, bile duct dilatation (grade ≥ 2) was also significantly more prevalent (P < 0.0001). These results are concordant with previous reports showing a higher endemicity of opisthorchiasis in Vientiane Municipality and in Savannakhet and Khammouane provinces.

Inverted Meckel diverticulum as a lead point of small bowel intussusception: misinterpreting case as a lipoma.

Inverted Meckel diverticulum is an uncommon cause of intussusception in adults. It may be confused for an intraluminal lipoma. We present a case of small bowel intussusception due to inverted Meckel diverticulum with characteristic computed tomography finding potentially distinguishable from lipoma.

The differentiation of autoimmune pancreatitis and pancreatic cancer using imaging findings.

BACKGROUND/AIMS: Differentiation of autoimmune pancreatitis (AIP) and pancreatic cancer (PC) is important to avoid unnecessary surgery. The aim of this study was to compare various image findings and facilitate the differentiation of these two diseases. METHODOLOGY: The radiological features of 36 AIP patients and 36 patients with resected PC diagnosed at Samsung Medical Center from January 1991 to October 2010, were compared. RESULTS: Regarding CT/MRI findings, diffuse pancreas enlargement, capsule-like rim and delayed homogenous enhancement, were significantly more frequent in AIP. For cholangiopancreatography findings, main pancreatic duct (MPD) narrowing by ≥1/3 of the pancreatic length, skipped lesions of the MPD, the presence of side branches at the narrowed MPD portion, and smooth and straight intrapancreatic common bile duct stenosis were significantly more frequent in AIP. However, according to FDG-PET findings, SUVmax, uptake shape and pattern, and uptake by extrapancreatic lesions were not significantly different for AIP and PC. CONCLUSIONS: Diffuse pancreas enlargement, a capsule-like rim, delayed homogenous enhancement, MPD narrowing of ≥1/3 of the pancreatic length, skipped lesions and the presence of side branches at the narrow MPD portion were found to have high specificity for AIP. These findings have great power to differentiate AIP and PC.

Intraductal growing acinar cell carcinoma of the pancreas.

Acinar cell carcinoma (ACC) is a rare pancreatic exocrine neoplasm characterized by a huge, exophytic well-circumscribed hypovascular mass. There has been several reports describing intraductal and papillary variant of ACC and they showed different radiologic features from usual ACC. We present histologically confirmed cases of intraductal and papillary variant of ACC that had been found in two patients, who underwent CT and MRI. This report provides CT and MRI features of intraductal and papillary variant of ACC in pancreas with pathologic correlation after surgical excision.

Intraductal papillary neoplasm of the bile ducts: description of MRI and added value of diffusion-weighted MRI.

PURPOSE: To evaluate MRI features of intraductal papillary neoplasm of the bile duct (IPNB) and to determine added value of diffusion-weighted MRI (DWI). METHODS: Twenty-three patients with surgically confirmed invasive (n = 12) and non-invasive (n = 11) IPNB, who underwent preoperative liver MRI were included. Two observers performed consensus review of gadoxetic acid-enhanced MRI and combined gadoxetic acid-enhanced MRI including DWI separately, with regard to conspicuity of intraductal tumor using five point scales, extent of tumors, and the presence of invasiveness. RESULTS: On MRI, there was no significant difference in the conspicuity of intraductal tumors between gadoxetic acid MRI (mean, 4.35) and combined MRI (mean, 4.65) (P = 0.09). However, addition of DWI led seven cases revealed excellent conspicuity as compared with good or moderate conspicuity on gadoxetic acid MRI. With regard to invasiveness, 11 cases (48 %) and 17 (74 %) were correctly diagnosed with gadoxetic acid MRI and combined MRI, respectively (P = 0.06). In invasive tumors, both of the two image sets did not help assess accurate extent of the tumor. CONCLUSIONS: The addition of DWI to gadoxetic acid-enhanced MRI has a potency to improve conspicuity for intraductal tumors of IPNB and is helpful in determining tumor invasiveness, but not tumor extent.

Prediction of carcinoma after resection in subjects with ampullary adenomas on endoscopic biopsy.

BACKGROUND/GOALS: The endoscopic treatment of ampullary adenomas is established; however, the false-negative rate of endoscopic biopsy for carcinoma is 20% to 30%, and it remains uncertain whether identifiable features predict malignancy. Our aim in this study was to evaluate the predictable factors of malignancy in ampullary adenomas on endoscopic biopsy. STUDY: Ninety-one subjects diagnosed with ampullary adenoma on endoscopic biopsy were confirmed after endoscopic or surgical resection of ampullary lesions between 1995 and 2011 respectively. Clinical, laboratory, radiologic, and endoscopic findings were compared between patients with adenoma and carcinoma after resection. We examined the predictors of malignancy in ampullary adenoma on endoscopic biopsy. RESULTS: The malignancy rate in ampullary adenomas on endoscopic biopsy was 26.4%. Univariate analysis revealed that presence of symptoms, villous components, high-grade dysplasia (HGD), papilla enlargement on computed tomography, duct dilatation on radiologic imaging, bilirubin>2 mg/dL, aspartate aminotransferase>40 IU/L, alanine aminotransferase>40 IU/L, and alkaline phosphatase>90 U/L were associated with malignancy in patients over 65 years of age. HGD [odds ratio, 6.86 (95% confidence interval, 1.58-29.79)] and ductal dilatation [odds ratio, 11.12 (95% confidence interval, 2.27-54.37)] were independently associated with malignancy in multivariate analysis. The sensitivity and negative predictive value for ≥1 risk factors were 95.83% and 96.77%, respectively. The presence of 2 risk factors resulted in a high specificity (96%) and positive predictive value (84%) for malignancy. CONCLUSIONS: HGD and ductal dilatation are significant predictors of malignancy in ampullary adenomas. When these risk factors are present, precautions should be taken in the consideration of malignancy in patients with ampullary adenoma.

Peritoneal manifestations of fascioliasis on CT images: a new observation.

PURPOSE: To describe peritoneal manifestations of fascioliasis on CT. MATERIALS AND METHODS: We reviewed CT images in 31 patients with fascioliasis confirmed by enzyme-linked immunosorbent assay (ELISA) (n = 24) or surgery (n = 7). Image analyses were performed to identify hepatic, biliary, and peritoneal abnormalities. RESULTS: Hepatic abnormalities were seen in 28 (90.3 %) of the 31 patients. The most common finding was caves sign, which was present in 25 (80.1 %) patients. Three patients (9.7 %) presented with biliary abnormalities exhibiting dilatation and enhancing wall thickening of the bile duct, wall thickening of the gallbladder, and elongated structures in the bile duct or gallbladder. Peritoneal abnormalities were seen in 14 (45.2 %) of the 31 patients. The most common peritoneal abnormality was mesenteric or omental infiltration, which was seen in 9 (29.0 %) patients. Other peritoneal findings included lymph node enlargement (n = 7), ascites (n = 7), thickening of ligamentum teres (n = 2), and peritoneal mass (n = 2). CONCLUSION: Peritoneal manifestations of fascioliasis are relatively common, and CT findings include mesenteric or omental infiltration, lymph node enlargement, ascites, thickening of the ligamentum teres, and peritoneal masses.

Clinicoradiologic characteristics and outcomes of metastatic cancer to the pancreas and double primary pancreatic cancer.

OBJECTIVES: The goal of this study was to identify clinicoradiologic characteristics to distinguish metastatic cancer to the pancreas (MCP) from double primary pancreatic cancer (DPPC). METHODS: From 2000 to 2011, we retrospectively identified MCP and DPPC patients among patients with histories of other primary malignancies. RESULTS: A total of 94 patients with histories of other primary malignancies were histologically confirmed to have pancreatic cancer. Among them, 34 patients had MCP and 60 patients had DPPC, which were ductal adenocarcinomas. The kidney was the most common primary cancer site that metastasized to the pancreas (12, 35.3%). In the DPPC group, the stomach was the most common primary cancer site (11, 18.3%). There were 21 patients (61.8%) with metachronous pancreatic cancer in the MCP group and 29 (48.3%) in the DPPC group (P=0.210). Among the metachronous pancreatic cancer patients, the disease-free interval was 88.3 months in the MCP group, and 49.6 months in the DPPC group (P=0.062). The number of the patients who showed elevated CA 19-9 levels was higher in the DPPC group than in the MCP group (39 (65%) vs. 9 (26.5%); P=0.001). Total bilirubin (P=0.006) and fasting plasma glucose (P=0.050) were also higher in the DPPC group. The numbers of patients who showed pancreatic duct dilatation (P=0.002) and pancreatic atrophy (P=0.008) on radiographs were meaningfully higher in the DPPC group than in the MCP group. On the other hand, the numbers of patients who showed well demarcated tumor margin (P<0.000), tumor necrosis (P=0.002), enhancement (P=0.005) and distant metastasis (P=0.028) were significantly higher in the MCP group than in the DPPC group. We evaluated differences in survival between the two groups. The median survival time in the MCP group (55 months) was significantly longer than that in the DPPC group (20 months). CONCLUSIONS: Other than elevated levels of CA 19-9, total bilirubin and fasting glucose, radiologic findings were the most reliable factors for distinguishing the MCP from the DPPC.

Solid pseudopapillary tumor of the pancreas with hepatic metastasis: spontaneous regression over 10-year follow-up period.

A solid-pseudopapillary tumor (SPT) of the pancreas is known as a low grade malignant tumor with a good prognosis; therefore, surgical intervention is necessary. A 14-year-old boy presented with a large pancreatic SPT and three hepatic metastases. The patient and his family refused surgery. Two serial follow-up CT scans over a period of 13 years demonstrated almost complete disappearance of the pancreatic tumor and three hepatic metastases without relevant treatment. Although there have been a few reports of spontaneous healing of SPT, there has been no report regarding spontaneous disappearance of SPT and distant metastasis. Herein, we report on the spontaneous regression of a large SPT and the disappearance of three hepatic metastases.

Diagnostic accuracy and sensitivity of diffusion-weighted and of gadoxetic acid-enhanced 3-T MR imaging alone or in combination in the detection of small liver metastasis (≤ 1.5 cm in diameter).

PURPOSE: To compare the diagnostic accuracy and sensitivity of combined gadoxetic acid-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) with each imaging approach alone for detecting small hepatic metastases (≤ 1.5 cm). MATERIALS AND METHODS: Institutional review board approved this retrospective study and waived informed patient consent. Eighty-six patients with 179 liver metastases underwent liver MRI including unenhanced and gadoxetic acid-enhanced imaging and DWI at 3.0 T. Three image sets including unenhanced images-gadoxetic acid set (early dynamic and hepatocyte phase), DWI set, and the combined set-were analyzed independently and in consensus by 2 observers for detecting liver metastases using receiver operating characteristic analysis. RESULTS: There was a tendency toward an increased diagnostic accuracy for the combined set (mean, 0.965) compared with that for each image set alone (mean, 0.911 for gadoxetic acid set; 0.926 for DWI set). The combined set showed better sensitivity (mean, 97.47%/95.0%: values on per-lesion/per-patient basis) than each imaging set alone (mean, 90.7%/83.7% for gadoxetic acid set; 91.6%/83.0% for DWI set) (P < 0.05) on both per-lesion basis and per-patient basis. All image sets showed similar positive predictive values. CONCLUSIONS: The combination of gadoxetic acid-enhanced MRI and DWI yielded better diagnostic accuracy and sensitivity in the detection of small liver metastasis than each magnetic resonance scan sequence alone.

Clinicopathologic features of intraductal papillary neoplasm of the bile duct according to histologic subtype.

OBJECTIVES: Despite an increase in the reports of intraductal papillary neoplasm of the bile duct (IPN-B), the clinical characteristics and long-term prognosis of this disease are not well known compared with those of intraductal papillary mucinous neoplasms of the pancreas. The objective of our study was to compare the clinical features, radiologic findings, and clinical outcomes of IPN-B according to histologic subtype. METHODS: A retrospective analysis was performed on the medical records of 97 patients diagnosed with IPN-B by pathologic analysis of their surgical specimens between May 1995 and May 2010. We compared the clinical manifestations, radiological findings, pathologic grade, curative resection rate, recurrence, and overall survival according to four histologic subtypes: gastric (n=15), intestinal (n=46), pancreaticobiliary (n=33), and oncocytic (n=3), which were classified on the basis of hematoxylin and eosin staining and the immunohistochemical profile of mucin core proteins. RESULTS: Mucin hypersecretion was significantly more frequent in patients with gastric and intestinal types than it was in those with oncocytic and pancreaticobiliary types (P=0.014). There were no significant differences between groups regarding the presence of bile duct stones or tumor location. The frequency of invasive carcinoma in the pancreaticobiliary type was significantly higher than those in the gastric and intestinal types (72.7 vs. 26.7 and 32.6%, P<0.001 and P<0.001). When comparing the survival curves according to histologic subtype, patients with pancreaticobiliary type demonstrated significantly worse survival compared to those with gastric and intestinal types (P=0.035). CONCLUSIONS: Gastric and intestinal types of IPN-B have similar clinical characteristics compared with the pancreaticobiliary type, which has a worse prognosis.

Cyst-forming intraductal papillary neoplasm of the bile ducts: description of imaging and pathologic aspects.

OBJECTIVE: Intraductal papillary neoplasm (IPN) of the bile duct is a newly described pathologic entity characterized by the presence of intraluminal tumors, which sometimes produce a large amount of mucin and form a cystic tumor. Cystic IPN of the bile duct is different from biliary cystadenoma or cystadenocarcinoma in that the former produces intraductal microscopic and macroscopic papillary tumors without ovarian-like stroma, whereas the latter produce a mucin-containing septate cystic tumor without communication with bile duct and with ovarian-like stroma in the cyst wall. The purpose of this study was to evaluate the potential relationships between cyst-forming IPNs of the bile duct and peribiliary glands and also intraductal papillary mucinous neoplasms of the pancreas. MATERIALS AND METHODS: From a cohort of 87 patients with surgically resected and pathologically proved IPN of the bile duct, 12 patients with cystic IPN of the bile duct who underwent CT (n = 12), MRCP (n = 3), ultrasound (n = 3), and ERCP (n = 4) were included. Imaging findings were evaluated for the relationship of cystic tumors to the bile ducts; in particular, a diverticulum-like appearance was considered as suggestive of the peribiliary gland origin. Pathologic examination was conducted, and both gross and microscopic findings were recorded. RESULTS: Radiologic examination revealed aneurysm-like dilatation of the involved bile ducts in five patients and intrahepatic biliary cystic tumor in two patients. Interestingly, the remaining five patients had diverticulum-like cystic tumor with or without communication; one patient had a cystic tumor laterally attached to the extrahepatic bile duct. Histopathologically, cystic tumors are lined by atypical biliary epithelium showing intracystic papillary proliferation, with an appearance similar to that of pancreatic intraductal papillary mucinous neoplasm. CONCLUSION: This study suggests that cyst-forming IPN of the bile duct may be a biliary counterpart to pancreatic intraductal papillary mucinous neoplasm. In particular, at least some of the tumors seem to arise from peribiliary glands, and these cases might be a counterpart to branch-duct intraductal papillary mucinous neoplasm of the pancreas, given the histologic similarity between peribiliary glands and pancreatic branch ducts.

Preoperative evaluation of the longitudinal extent of borderline resectable hilar cholangiocarcinoma by intraductal ultrasonography.

BACKGROUND AND AIM: In patients with hilar cholangiocarcinoma (HC), longitudinal tumor extent is important for curative resection. The purpose of this study was to evaluate the longitudinal extents of HC using transpapillary intraductal ultrasonography (IDUS) for optimal surgical planning. METHODS: From July 2006 to April 2010, a total of 42 patients with borderline resectable HC were enrolled at Samsung Medical Center, a tertiary referral hospital in Seoul, Korea. All patients were evaluated using multi-detector computed tomography (MDCT), endoscopic retrograde cholangiopancreatography (ERCP) and IDUS. The new modified Bismuth Type (MBT) classification, in which the traditional Bismuth type IV stage is divided into stages IVa and IVb, was used to determine whether the tumor invaded the left lateral section. Among the subtypes of HC, the periductal infiltrative type (PDI) and intraductal papillary neoplasm of the bile duct (IPN-B) were compared. The accuracies of CT, ERCP, and IDUS were assessed through comparison with the postoperative histology findings. RESULTS: A total of 42 patients were prospectively enrolled, and the tumor extent could be assessed histologically in 30 patients. The accuracies of CT, ERCP, and IDUS were 66.6%, 60%, and 90%, respectively. The accuracy of IDUS was 85.7% in 21 patients with PDI and 100% in nine patients with IPN-B. CONCLUSIONS: Hilar cholangiocarcinoma staging based on IDUS findings was highly accurate. We therefore highly recommend using IDUS for optimal surgical planning in patients with borderline resectable HC.

Liver flukes: the malady neglected.

Liver fluke disease is a chronic parasitic inflammatory disease of the bile ducts. Infection occurs through ingestion of fluke-infested, fresh-water raw fish. The most well-known species that cause human infection are Clonorchis sinensis, Opisthorchis viverrini and Opisthorchis felineus. Adult flukes settle in the small intrahepatic bile ducts and then they live there for 20-30 years. The long-lived flukes cause long-lasting chronic inflammation of the bile ducts and this produces epithelial hyperplasia, periductal fibrosis and bile duct dilatation. The vast majority of patients are asymptomatic, but the patients with heavy infection suffer from lassitude and nonspecific abdominal complaints. The complications are stone formation, recurrent pyogenic cholangitis and cholangiocarcinoma. Approximately 35 million people are infected with liver flukes throughout the world and the exceptionally high incidence of cholangiocarcinoma in some endemic areas is closely related with a high prevalence of liver fluke infection. Considering the impact of this food-borne malady on public health and the severe possible clinical consequences, liver fluke infection should not be forgotten or neglected.

Morphology of intraductal papillary neoplasm of the bile ducts: radiologic-pathologic correlation.

PURPOSE: Intraductal papillary neoplasm of the bile duct (IPN-B) is known as a premalignant lesion of invasive cholangiocarcinoma. The purpose of this study was for radiologic-pathologic correlation of morphologic features of IPN-B and to correlate the subclassifications with biological behavior in regard to the bile duct wall invasion. MATERIALS AND METHODS: A pathologist classified gross morphology of 75 cases (44 men and 31 women, age range, 39-85) of histopathologically proven IPN-B into polypoid, cast-like, superficial-spreading, and cyst-forming type. Preoperative images were retrospectively reviewed by two observers independently and classified the gross appearance of intraductal tumors into the four types. RESULTS: The pathologist classified macroscopic appearances of 75 cases of IPN-B into polypoid type in 26, cast-like intraductal growth in 17, superficial-spreading growth in 21, and cyst-forming type in 11. Two observers classified image findings in accordance with pathologist's classification in 58 and 57 (77% and 76%) among the 75 cases of IPN-B, respectively; 18 and 19 of 26 cases of polypoid type, 14 and 14 of 17 cases of cast-like growth type, 16 and 19 of 21 cases of superficial-spreading type, 10 and 5 of 11 cases of cyst-forming type, respectively. Interobserver agreement for subclassification of tumor morphology was in the category of good agreement (k = 0.651). There was no correlation between morphological subclassification and tendency to invasive cholangiocarcinoma. CONCLUSION: IPN-Bs can be classified morphologically into polypoid, cast-like growth, superficial-spreading, and cystic type, but there is no correlation between the types and tendency to invasive cholangiocarcinoma.

The clinicopathological features of biliary intraductal papillary neoplasms according to the location of tumors.

BACKGROUND AND AIM: In this study, we analyzed the clinical and pathological features of biliary intraductal papillary neoplasms (IPN-B) according to the location of the tumors. METHODS: A total of 55 patients with IPN-B were analyzed. We divided them into three groups: common bile duct (CBD), hilar, and intrahepatic duct (IHD) groups. The clinical and laboratory findings, cell types, depth of invasion, malignancy, existence of stones, lymph node metastasis, recurrence, and survival rate were analyzed. RESULTS: There was no difference in the depth of invasion, lymph node metastasis, and coexistence of stones between the three groups. There were four different cell types; the intestinal cell type was the most common type in each group. The gastric cell type was prevalent in the IHD and hilar groups (58.3% and 33.3%, respectively). Invasive colloid carcinoma mainly showed the intestinal cell type, and tubular carcinoma showed the pancreaticobiliary cell type. There was a trend that malignancy was more prevalent in the CBD group (94.1%) than in the hilar group (64.3%) and IHD group (79.2%), but there was no statistically significant difference. There was no difference in the recurrence rate and the 3-year survival rate between the three groups. CONCLUSION: IPN-B showed no difference in the malignancy and survival rates according to the location of the tumors. Because IPN-B show good prognosis after surgery, aggressive surgical resection for the treatment of IPN-B is recommended.

Mucin-producing bile duct tumors: radiological-pathological correlation and diagnostic strategy.

Mucin-producing bile duct tumors are characterized by intraductal papillary tumors producing large amounts of mucin. The tumor comprises macroscopically prominent intraductal papillary neoplastic epithelia and produces a large amount of viscid mucin, resulting in dilatation of the bile ducts. The surface of the tumor is frond-like, velvety, or serrated. The tumor exhibits five intraductal growth patterns; polypoid intraductal growth, mucosal spreading growth, cast-like intraductal growth, cystic tumor, and intraductal floating tumors. Imaging features reflect the interplay between the morphology of the tumor, the amount of mucin production, and biliary dilatation. This review article describes the radiological manifestations of the tumor, based on pathological-radiological correlation and biological behavior.

Distinguishing xanthogranulomatous cholecystitis from the wall-thickening type of early-stage gallbladder cancer.

BACKGROUND/AIMS: Xanthogranulomatous cholecystitis (XGC) mimics early-stage gallbladder (GB) cancer with wall thickening on computed tomography (CT), both clinically and radiologically. Preoperative differentiation of XGC from early-stage GB cancer is important for selecting the most appropriate surgical management. Therefore, we evaluated the clinical features and multidetector CT (MDCT) findings of XGC to determine whether it can be distinguished from early-stage GB cancer. METHODS: We retrospectively evaluated 25 patients with XGC and 56 patients with the wall-thickening type of T1- and T2-stage GB cancer, where all of the diagnoses were pathologically confirmed by surgical treatment. All of the patients underwent preoperative MDCT. The clinical symptoms, laboratory findings, and CT findings were compared. RESULTS: Abdominal pain, fever, and jaundice were noted more frequently in the patients with XGC. Serum aspartate aminotransferase and alanine aminotransferase levels were more elevated in patients with XGC, whereas carbohydrate antigen (CA 19-9) was higher in the patients with GB cancer. When the T-category cancer staging of XGC and early-stage GB cancer were compared, diffuse GB wall thickening, intramural hypoattenuated nodule, gallstone, and pericholecystic infiltration were consistent significant findings associated with XGC, regardless of the cancer staging. CONCLUSIONS: MDCT findings such as diffuse GB wall thickening, intramural hypoattenuated nodule, gallstone, and pericholecystic infiltration together with the clinical symptoms, can provide clues for physicians to differentiate XGC from early-stage GB cancer with wall thickening on CT.

The clinical and radiological characteristics of focal mass-forming autoimmune pancreatitis: comparison with chronic pancreatitis and pancreatic cancer.

OBJECTIVES: We investigated the clinical and radiological features of focal mass-forming autoimmune pancreatitis (FMF AIP) to help physicians avoid performing unnecessary surgery because of an improper diagnosis. METHODS: We evaluated 23 patients with chronic inflammatory pancreatic masses and who underwent pancreatectomy for presumed pancreatic cancer from April 1995 to December 2005. These patients were distinguished into 8 FMF AIP patients and 15 ordinary chronic pancreatitis patients through a histological review, along with considering the immunoglobulin G4 staining. Twenty-six randomly selected pancreatic cancer patients were also evaluated as a control group. RESULTS: On the portal venous phase of computed tomography, 6 (85.7%) of 7 FMF AIP patients showed homogeneous enhancement, whereas only 3 chronic pancreatitis patients (25%) and none of the pancreatic cancer patients showed homogeneous enhancement (P < 0.001). None of the FMF AIP patients showed upstream main pancreatic duct dilatation greater than 5 mm or proximal pancreatic atrophy. CONCLUSIONS: For patients with a pancreatic mass, if their radiological images show homogeneous enhancement on the portal venous phase, the absence of significant upstream main pancreatic duct dilatation greater than 5 mm, and the absence of proximal pancreatic atrophy, then conducting further evaluations should be considered to avoid performing unnecessary surgery.