Endoluminal ultrasonography for pancreatic diseases.

Endoluminal ultrasonography was performed on 146 patients with pancreatobiliary diseases by using high-frequency, thin ultrasonic probes, and the usefulness of the new technique in diagnosis of pancreatic diseases was reported. The ultrasound probe could be inserted into the main pancreatic duct in 43 of 46 patients (93.5%), and images of the lesions could be obtained in 42 patients (91.3%). Endoluminal ultrasonography revealed a hypoechoic mass with clear margins and central echogenicity in patients with pancreatic carcinoma. Endoluminal ultrasonography showed normal pancreatic parenchyma as a fine reticular pattern and did not reveal the tumors surrounding the stenosis in patients with focal pancreatitis. Endoluminal ultrasonography in patients with intraductal papillary adenocarcinoma of the pancreas revealed cystic lesions with mural nodules more than 4 mm, mucus echoes, and solid tumors with mixed echo patterns. There were no severe complications, and acute pancreatitis occurred in none of 46 patients, but high-level serum amylase after examination occurred in 5 patients (10.9%). Endoluminal ultrasonography is useful for differential diagnosis in patients with small pancreatic tumors or cystic lesions, especially intraductal papillary tumors of the pancreas. Endoluminal ultrasonography is recommended as a precise examination for the diagnosis of cystic lesions of the pancreas or stenosis of the main pancreatic duct after ERCP and EUS.     

Preoperative evaluation of malignancy in intraductal papillary mucinous neoplasms of the pancreas, especially in relation to dysplastic epithelial changes

BACKGROUND/AIMS: Intraductal papillary mucinous neoplasms have a better prognosis than ductal adenocarcinomas of the pancreas. The aim of this study was to evaluate the malignant potential of IPMNs by their preoperative images. METHODOLOGY: Forty-three intraductal papillary mucinous neoplasms were divided into 3 duct ectatic types using preoperative images (the main duct type, the branch duct type, and the mixed type), and into 2 groups using resected specimens (the malignant group including severe dysplasia based on the WHO classification and the benign group). The diameters of the tumor, main pancreatic duct and mural nodule were measured on the images. RESULTS: Two thirds of main duct type cases were in the malignant group. For the branch duct and mixed types, the diameters of the tumor and detectable mural nodules were larger in the malignant group than in the benign group. A tumor diameter larger than 3.5cm and a mural nodule diameter larger than 6mm were risk factors for malignancy (p < 0.05). CONCLUSIONS: The main duct type, a tumor larger than 3.5cm of the branch duct or mixed type, and a mural nodule larger than 6mm were all indicators of malignancy risk.     

Intraductal papillary adenocarcinoma with mucin hypersecretion and coexistent invasive ductal carcinoma of the pancreas with apparent topographic separation

We report a 66-year-old man who had a cystic intraductal papillary adenocarcinoma containing a papillary adenoma, in the head of the pancreas and a coexistent invasive, well differentiated solid tubular adenocarcinoma in the tail of the pancreas. He was hospitalized with acute epigastralgia. Computed tomography demonstrated a multilocular cystic mass in the head of the pancreas and a solid tumor in the tail. Endoscopic retrograde pancreatography showed mucin secretion from an enlarged papilla of Vater, marked dilatation of the main pancreatic duct in the head and body, cystic dilatation of the uncinate branch, and irregular narrowing of the main pancreatic duct in the tail. Total pancreatectomy was performed. Between the cystic tumor and the solid tumor there was a distance of 4.8 cm of normal pancreatic parenchyma and duct, recognized both grossly and microscopically. The patient died 35 months after the operation. At autopsy, peritonitis carcinomatosa was found in the abdominal cavity. Microscopically, disseminated nodules were also well differentiated tubular adenocarcinoma. The apparent anatomic separation of these two tumors within the pancreas is extremely unusual.     

Intraductal papillary and mucinous tumor of the pancreas: a case report of successful surgical treatment with decompression

Intraductal papillary mucinous tumor of the pancreas is commonly regarded as histopathologically low-grade malignancy. As yet, no fixed strategy of treatment for the advanced aged patient with intraductal papillary mucinous tumor exists. An 80-year-old woman was admitted to our hospital in July 1996 because of back pain due to pancreatitis. Examinations showed a widely opened orifice of the ampulla of Vater, the mural nodule in the cystic lesion of the pancreas uncus, and a mucinous plug in the diffusely dilated main pancreatic duct, so the patient was diagnosed as having intraductal papillary mucinous tumor in the pancratic head. However, in view of the patient's advanced age and the fact that intraductal papillary mucinous tumor is commonly regarded as a slow growing and histopathologically low-grade malignancy, we refrained from radical operation and selected the best supportive care. Four years subsequent to this, her symptoms became uncontrollable and she returned to our hospital. In consideration of her age, side-to-side pancreaticojejunostomy as minimally invasive surgery was employed. The postoperative course was uneventful. The symptoms, biochemical profiles and images improved and she was discharged from the hospital 28 days after the operation. No event has been observed in the patient for one year after operation. Surgical decompression is considered to be effective minimally invasive surgery for intraductal papillary mucinous tumor.     

Intraductal oncocytic papillary neoplasm of the pancreas with strong accumulation on FDG-PET

This paper reports a case of resected intraductal oncocytic papillary neoplasm (IOPN) of the pancreas. A 69-year-old woman was admitted with right hypochondriac pain. Ultrasonography, contrast-enhanced computed tomography and magnetic resonance imaging showed a cystic lesion, 10cm in diameter, in the head of the pancreas. The lesion contained a number of mural nodules 1cm in diameter with thick walls, which demonstrated hypervascularity. The main pancreatic duct was slightly dilated, 7mm in diameter. 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) showed very strong uptake in the thick wall and mural nodules of the tumor. Substomach-preserving pancreatoduodenectomy (SSPPD) was performed. The patient is presently alive and well without any evidence of recurrent disease 18 months after the operation. IOPN has the potential to develop into invasive carcinoma, and therefore, should be completely resected whenever possible.     

Single-branch resection of the pancreas

The treatment of intraductal papillary mucinous tumors (IPMT) of the pancreas is still controversial. In this report we describe a single‐branch resection of the pancreas (SBRP), which is a new method for the removal of branch‐type IPMT of the head of the pancreas. A multilobular cystic lesion (50 × 40 mm) in the head of the pancreas was incidentally detected in an asymptomatic 40‐year‐old man who underwent a routine ultrasound examination. The tumor was carefully removed along the border of the cyst and the normal parenchyma, with complete preservation of the main pancreatic duct and the common bile duct. A pancreatic fistula developed during the postoperative period, but was well‐controlled by endoscopic naso‐pancreatic drainage. SBRP is a technically feasible procedure and this operation represents a minimally invasive alternative to any other segmental resection of the pancreas.     

Intraductal papillary-mucinous adenoma developed in the ventral pancreas in a patient with pancreas divisum

A 34-year-old man was admitted to our hospital with the chief complaints of back pain and epigastralgia. The physical examinations on admission disclosed no abdominal tumor. The serum concentration of total bilirubin was 1.4?mg/dl. The serum elastase-1 level was elevated to 526?ng/dl. Computed tomography showed a cystic lesion, 1?cm in diameter, in the head of the pancreas, without dilatation of the main pancreatic duct. Endoscopic retrograde cholangiopancreatography via the papilla of Vater and the accessory papilla revealed an enlarged ventral pancreatic duct and pancreas divisum. The preoperative diagnosis was mucin-producing pancreatic tumor in the ventral pancreas of a patient with pancreas divisum. A pylorus-preserving pancreatoduodenectomy was performed. The gross findings of the cut surface of the resected specimen disclosed mural nodules in the dilated duct of the ventral pancreas. A histological examination of the mural nodules in the ventral pancreas revealed mucin and intraductal papillary adenoma. Benign tumors associated with pancreas divisum are rare; to the best of our knowledge, only three cases have been reported. Although in these three patients the tumor developed in the dorsal pancreas, the tumor developed in the ventral pancreas in our patient.     

EUS in the evaluation of pancreatic cystic lesions

BACKGROUND: The differential diagnosis in pancreatic cystic lesions is often difficult despite the availability of various modern imaging modalities. This study assessed the role of EUS in the following: (1) discrimination of pseudocysts from pancreatic cystic tumors, (2) differential diagnosis between serous cystadenoma and mucinous cystic tumor, and (3) prediction of accompanying malignancy in intraductal papillary mucinous tumor. METHODS: EUS findings in 75 patients with pancreatic cystic lesions (58 cystic tumors, 17 pseudocysts) were evaluated. In the comparison of pseudocysts and cystic tumors, the latter included intraductal papillary mucinous tumor, mucinous cystic tumors, and serous cystadenomas, but not solid-pseudopapillary tumors. RESULTS: In univariate analysis, pseudocysts exhibited echogenic debris and parenchymal changes more often than cystic tumors did (respectively, 29% vs. 6%, p < 0.05; and 65% vs. 4%, p < 0.001). In contrast, septa and mural nodules were found more frequently in cystic tumors than pseudocysts (respectively, 69% vs. 12%, p < 0.001; 56% vs. 12%, p < 0.01). Multivariate analysis revealed that parenchymal changes (odds ratio [OR] = 83.59; p < 0.01); septa (OR = 30.75; p < 0.05); and mural nodules (OR = 21.38; p < 0.05) were independent predictors of differentiation between pseudocysts and cystic tumors. Serous cystadenoma exhibited diverse EUS features, as well as a honeycomb appearance. Mural nodules were found more often in mucinous cystic tumors than in serous cystadenomas (p < 0.05). There were no factors that predicted malignancy in intraductal papillary mucinous tumor. CONCLUSIONS: EUS is a useful complementary imaging method for differentiation of pancreatic cystic lesions.     

Inferior head resection of the pancreas for noninvasive intraductal papillary mucinous adenocarcinoma

We report inferior head resection of the pancreas for noninvasive intraductal papillary mucinous cancer. A 77-year-old man was admitted to our hospital complaining of epigastric pain. Contrast-enhanced computed tomographic scan and magnetic resonance imaging showed a multilocular cystic tumor 3.5 cm in diameter in the head of the pancreas. We performed inferior head resection of the pancreas with partial resection of the duct of Santorini. The duodenum, the common bile duct, and most of the duct of Santorini were preserved. He is presently alive and well without any evidence of recurrent disease 49 months after the operation. Partial pancreatic resection has the advantage of preserving pancreatic parenchyma. Inferior head resection of the pancreas would play an important role in surgical management of low-grade malignant neoplasm.     

Intraductal papillary adenoma: Usefulness of magnetic resonance cholangiopancreatography in the diagnosis of cystic branch-duct dilatation of the pancreas

A 70-year-old woman with gastric cancer was referred to our hospital for further evaluation of a cystic mass in the head of the pancreas. Endoscopic ultrasonography (EUS) showed a mural nodule in the cystic mass. Endoscopic retrograde cholangio pancreatography (ERCP) revealed a cystic lesion with a filling defect caused by obstruction with mucus. Magnetic resonance cholangiopancreatography (MRCP) allowed visualization of the entire configuration of the cystic lesion despite the presence of mucus. Pancreatic juice was positive for K-ras point mutation. Pancreatoduodenectomy was performed, with a diagnosis of intraductal papillary adenoma or adenocarcinoma with gastric cancer. Pancreatography of the resected specimen showed a cystic lesion in the uncinate process, consistent with the MRCP findings. Histological examination revealed an intraductal papillary adenoma. MRCP is very useful for demonstrating the total configuration of cystic lesions and is not impeded by impacted mucin. Nevertheless, because of its lower spatial resolution, this noninvasive modality is of limited value in detecting mural nodules. At present, therefore, surgical indications for cystic lesion of the pancreas should be determined by comprehensively analyzing: size and sequential changes in size of the cyst; presence of mural nodules, cytologic examination for presence of malignant cells, and/or K-ras point mutation in pure pancreatic juice.     

A pancreatobiliary-type carcinoma in situ at the periphery of a mural nodule developed from a gastric adenoma in an intraductal papillary mucinous neoplasm

We report a rare case of an intraductal papillary mucinous neoplasm (IPMN) with a pancreatobiliary-type carcinoma in situ (CIS) that originated around a mural nodule formed in a gastric-type adenoma. A 64-year-old man was admitted to our hospital in December 2001 for dilation of the main pancreatic duct, detected on abdominal ultrasonography. Branch-duct-type IPMN (diameter 25 mm) was diagnosed, and because mural nodules were absent, the patient was annually followed up for 5 years. In 2006, computed tomography scans revealed thickening of the tumor wall and the development of a mural nodule (diameter approximately 6 mm); pancreatoduodenectomy with regional lymph-node dissection was performed. Histopathologic examination showed an intraductal papillary mucinous carcinoma arising from an adenoma. Hematoxylin and eosin (H&E) staining revealed that most of the tumor components, including the mural nodule, had adenomatous changes, indicating the tumor to be of the gastric type; however, immunohistochemistry showed positive MUC2 expression. Histologically, the tissues around the nodule, including those showing a cribriform pattern, were diagnosed as CIS. These tissues were classified as the pancreatobiliary-type on the basis of the results of both H&E staining and immunohistochemistry. The patient remained disease-free for 3 years after surgery.     

European experts consensus statement on cystic tumours of the pancreas

Cystic lesions of the pancreas are increasingly recognized. While some lesions show benign behaviour (serous cystic neoplasm), others have an unequivocal malignant potential (mucinous cystic neoplasm, branch- and main duct intraductal papillary mucinous neoplasm and solid pseudo-papillary neoplasm). European expert pancreatologists provide updated recommendations: diagnostic computerized tomography and/or magnetic resonance imaging are indicated in all patients with cystic lesion of the pancreas. Endoscopic ultrasound with cyst fluid analysis may be used but there is no evidence to suggest this as a routine diagnostic method. The role of pancreatoscopy remains to be established. Resection should be considered in all symptomatic lesions, in mucinous cystic neoplasm, main duct intraductal papillary mucinous neoplasm and solid pseudo-papillary neoplasm as well as in branch duct intraductal papillary mucinous neoplasm with mural nodules, dilated main pancreatic duct >6 mm and possibly if rapidly increasing in size. An oncological partial resection should be performed in main duct intraductal papillary mucinous neoplasm and in lesions with a suspicion of malignancy, otherwise organ preserving procedures may be considered. Frozen section of the transection margin in intraductal papillary mucinous neoplasm is suggested. Follow up after resection is recommended for intraductal papillary mucinous neoplasm, solid pseudo-papillary neoplasm and invasive cancer.     

Operative indications for cystic lesions of the pancreas with malignant potential--our experience

BACKGROUND/AIMS: There are still many important but unclear points regarding the differential diagnosis and operative indications of cystic lesions of the pancreas with malignant potential. Studies of the clinicopathological and molecular biological characteristics of such diseases are necessary. In this paper, we discuss operative indications for this condition based on a review of the literature and our own experience. METHODOLOGY: Seven cases of serous cystadenoma and 9 cases of mucinous cystadenoma or cystadenocarcinoma of the pancreas that were operated on or autopsied in our department from 1980 to 1996 were analyzed clinicopathologically. Small cystic lesions incidentally found in 300 autopsied cases were also studied. Finally, mucin-producing tumors described in several reports were reviewed, and the branch type of this tumor was especially investigated. RESULTS: A marked disappearance of pancreatic acini in the upstream pancreas was found when serous cystadenoma became large. Papillary projection was histologically found in all of the cases. Tumorous invasion to the interstitium was suspected in tumors more than 5 cm in diameter, and malignancy was reported when tumors were larger than 6 cm. As for mucinous cystadenocarcinoma, the patients had a poor prognosis. In 2 of 42 cases with a pseudocyst, small duct cell carcinoma was incidentally found adjacent to the pseudocyst on the duodenal side. With regard to branch-type intraductal papillary neoplasm, 80% of the tumors larger than 4 cm were malignant. Most of the small cystic lesions found in elderly autopsy cases were accompanied by hyperplastic epithelia without evidence of malignancy. CONCLUSIONS: Based on our experience, an operation should be considered and resection is recommended under the following circumstances: 1) cystic lesions in the body and tail of the pancreas in middle-aged women; 2) typical serous cystadenoma larger than 4 cm; 3) mucinous cystadenoma of any size; 4) branch-type intraductal papillary neoplasm larger than about 3 cm; and, 5) pseudocysts of unknown cause. Small cystic lesions in elderly patients should not necessarily be operated on, but should be followed-up carefully.     

p53 protein expression in intraductal papillary mucinous tumors (IPMT) of the pancreas as an indicator of tumor malignancy

BACKGROUND/AIMS: Intraductal papillary mucinous tumors, as a cystic disease in the pancreas, clinically has a more indolent and favorable course than invasive ductal pancreas carcinoma. However, some cases of intraductal papillary mucinous tumors show invasive and rapid progression like ductal pancreas carcinoma and the prognosis of such patients is sometimes poor. In the current study, we carried out immunohistochemical staining of intraductal papillary mucinous tumor tissues for p53 and investigated whether positive staining indicates tumor malignancies and has a prognostic value for intraductal papillary mucinous tumors. METHODOLOGY: Nineteen (19) patients who underwent pancreatic resection under the diagnosis of intraductal papillary mucinous tumors at the Chiba University Hospital between April 1992 and December 1996 were studied. We performed immunohistochemical staining of p53 as well as of PCNA, Ki-67 and Bcl-2 using their respective antibodies. Pathological findings revealed that 9 cases were intraductal papillary adenoma, 9 were intraductal papillary adenocarcinoma, and one was invasive ductal papillary adenocarcinoma. RESULTS: p53 expression could only be detected in the 1 case with invasive ductal papillary adenocarcinoma. Significant association could not be found between histological features and immunohistochemical staining of PCNA, Ki-67 and Bcl-2. CONCLUSIONS: p53 protein expression could be detected after progression to invasive type of intraductal papillary mucinous tumors. The present results demonstrate that p53 expression might be an indicator of invasive progression in intraductal papillary mucinous tumors, and might represent a surgical indicator of intraductal papillary mucinous tumors.     

A case of an epithelial cyst arising in the intrapancreatic accessory spleen]

A 59-year old woman was admitted to our hospital for further examination of a cystic lesion detected in the tail of the pancreas. Imaging studies showed a 35-mm-diameter cystic lesion with septa and mural nodule at the same site. The mural nodule of the cyst was thick and was enhanced. Partial resection of the tail pancreas was performed with a preoperative diagnosis of pancreatic cystic tumor. The resected specimen showed mulitlobular cyst. Histologically, the internal surface of the cyst was covered with stratified squamous cells and the mural nodule of the cyst was spleen tissue. The final diagnosis was an epithelial cyst derived from an accessory spleen in the pancreas.     

A case of focal autoimmune pancreatitis (AIP) mimicking an intraductal papillary mucinous neoplasm (IPMN)

The present case involved a 76-year-old man with a cystic mass in the head of his pancreas. The cystic lesion, which measured 17.7 × 9.8 mm, was first detected by ultrasonography (US) at the age of 72 years. Follow-up endoscopic ultrasonography (EUS) performed at 4 years after the lesion had first been detected revealed a mural nodule measuring 14.0 × 8.4 mm in the cyst. Endoscopic retrograde pancreatography (ERP) imaging revealed that the main pancreatic duct was in communication with the cyst and that there was no irregular narrowing of the main pancreatic duct. On the basis of these results, the patient was diagnosed with an intraductal papillary mucinous neoplasm (IPMN), and stomach-preserving pancreaticoduodenectomy was performed. A histopathological examination revealed that the interior of the cystic part of the lesion was lined by a pancreatic ductal epithelium. A pathological examination of the nodular lesion detected storiform fibrosis, severe lymphoplasmacytic infiltration, and hyperplasia in the pancreatic duct epithelium together with a small amount of mucus. On immunohistological staining, the infiltrating lymphoplasmacytes were found to be positive for IgG4. Accordingly, the patient was diagnosed with focal autoimmune pancreatitis (AIP). In conclusion, we reported a case of focal AIP mimicking IPMN. This case showed neither enlargement of the pancreas nor irregular narrowing of the main pancreatic duct.     

Endoscopic ultrasonographic findings predict the risk of carcinoma in branch duct intraductal papillary mucinous neoplasms of the pancreas

BackgroundThe preoperative diagnosis of branch duct intraductal papillary mucinous neoplasm (IPMN) of the pancreas can be very difficult, since low-risk and high-risk lesions can be difficult to differentiate even after cytological analysis. The purpose of this study was to evaluate the preoperative diagnostic value of endoscopic ultrasonography (EUS) in differentiating low-risk and high-risk IPMNs.MethodsWe retrospectively identified 36 patients who underwent preoperative EUS for branch duct IPMNs. The pathological diagnosis after surgical resection was low-grade dysplasia (n = 26), moderate dysplasia (n = 1), high-grade dysplasia or carcinoma in situ (n = 5), and invasive carcinoma (n = 4). We divided the patients into two groups: low risk (low-grade dysplasia or moderate dysplasia) and high risk (high-grade dysplasia or carcinoma). We focused on the diameter of the cystic dilated branch duct, the main pancreatic duct, and the mural nodule as measured using the EUS findings.ResultsThe cystic dilated branch duct diameter (31.5 mm vs. 41.9 mm, P = 0.0225) was significantly correlated with low-risk and high-risk IPMNs, but the main pancreatic duct diameter (5.37 mm vs. 5.44 mm, P = 0.9418) was not significantly correlated with the low-risk and high-risk IPMNs. The mural nodule diameter of the papillary protrusions (4.3 mm vs. 16.4 mm, P < 0.0001) and the width diameter of the mural nodule (5.7 mm vs. 23.2 mm, P < 0.0001) were significantly correlated with low-risk and high-risk IPMNs.ConclusionsThe mural nodule of papillary protrusions diameter and width diameter observed using EUS was a reliable preoperative diagnostic finding capable of distinguishing low-risk and high-risk IPMNs.     

Immunohistochemical analysis of molecular biological factors in intraductal papillary-mucinous tumors and mucinous cystic tumors of the pancreas

BACKGROUND: To investigate the malignancy and differentiation of intraductal papillary-mucinous tumors (IPMTs) and mucinous cystic tumors (MCTs) of the pancreas, clinicopathologic characteristics and immunohistochemical features were analyzed. METHODS: The clinicopathologic characteristics and immunohistochemical features of 24 patients with IPMT and 8 with MCT who underwent pancreatic resections at our hospital were examined. Immunohistochemical features analyzed included expression of p53 protein, proliferating cell nuclear antigen, integrins, interleukin-1 receptor type I, and hormone-associated receptors, and the factors correlated with malignancy were identified by multiple logistic regression. RESULTS: Among the IPMTs, there were 16 intraductal papillary adenomas, 5 intraductal papillary adenocarcinomas, and 3 moderate dysplasias. Among the MCTs, there were 6 mucinous cyst adenomas and 2 mucinous cyst adenocarcinomas. Multivariate analysis revealed that of the clinicopathologic characteristics, only the presence of mural nodules (odds ratio (OR) 7.12, P = 0.044) was independently correlated with the malignancy of IPMTs, and that of the immunohistochemical features, only alpha integrin subunit expression was independently correlated with malignancy of pancreatic mucinous tumors (OR 15.6, P = 0.036), especially IPMTs (OR 35.7, P = 0.012). CONCLUSION: These results indicate that alpha-containing integrin expression can be a significant marker of malignancy in pancreatic mucinous tumors.     

Size of mural nodule as an indicator of surgery for branch duct intraductal papillary mucinous neoplasm of the pancreas during follow-up

Background

A mural nodule is a strong predictive factor for malignancy in branch duct intraductal papillary mucinous neoplasm (IPMN) of the pancreas, but the nodule size has hardly been considered. The aim of this study was to investigate whether a mural nodule of 10?mm was appropriate as an indicator of surgery for IPMN during follow-up.

Methods

The follow-up outcomes of 100 patients who had branch duct IPMN without mural nodules or who had branch duct IPMN with mural nodules of less than 9?mm in a tertiary care setting were investigated retrospectively. The patients underwent abdominal ultrasound (US) every 3?months and additional imaging examinations or cytologic examination of pancreatic juice when necessary. Surgery was recommended to them when a mural nodule developed or when a nodule enlarged and reached 10?mm.

Results

During an average follow-up period of 97?months, branch duct IPMNs developed mural nodules that reached 10?mm in 5 patients (0.62% per year). In one patient the IPMN was revealed to be non-invasive carcinoma by resection, 1 IPMN was shown to be malignant by further follow-up, and 3 were not resected because of refusal or the patient??s age. In 7 patients, mural nodules stayed within 9?mm. The remaining 88 patients lacked mural nodules in their branch duct IPMNs throughout the follow-up. The occurrence of invasive carcinoma around the IPMN was not indicated by imaging examinations in any patient. Univariate analysis showed that the size of the cyst at baseline significantly predicted the development of a mural nodule that reached 10?mm during follow-up (P?=?0.05).

Conclusions

A mural nodule of 10?mm is appropriate as an indicator of surgery in the follow-up of branch duct IPMN.     

Pancreatic tumor associated with pancreas divisum

BACKGROUND: Although there has been considerable controversy regarding pancreas divisum and pancreatitis, little discussion of this has taken place. The purpose of the present paper was to investigate the relationship between these two conditions. METHODS: A retrospective investigation was undertaken of pancreatic tumors associated with pancreas divisum, in 650 cases of pancreatic carcinoma, 80 cases of intraductal papillary mucinous tumor of the pancreas and 32 cases of pancreas divisum. RESULTS: Of these 32 cases, four (12.5%) were associated with pancreatic tumor: pancreatic carcinoma (n = 3) and intraductal papillary mucinous tumor (n = 1). All tumors developed from the dorsal pancreas of pancreas divisum. Periductal and interlobular fibrosis detected in the non-carcinomatous pancreas of the margin of distal pancreatectomy implied that chronic dorsal pancreatitis associated with pancreas divisum preceded carcinoma. CONCLUSIONS: Pancreatic tumors were detected in 12.5% of cases of pancreas divisum. In pancreas divisum, longstanding pancreatic duct obstruction caused by relative stenosis of the minor duodenal papilla might be a factor promoting oncogenesis.