Intraductal papillary neoplasm of the pancreas

Intraductal Papillary Mucinous Neoplasms of the Pancreas: Current Understanding and Future Directions for Stratification of Malignancy Risk

The incidence of intraductal papillary mucinous neoplasms (IPMNs) has been increasing over the past decade, mainly owing to increased awareness and the increased use of cross-sectional imaging. The Sendai and Fukuoka consensus guidelines provide us with clinical management guidelines and algorithms; however, the clinical management of IPMNs continues to be challenging. Our incomplete understanding of the natural history of the disease, and the events and pathways that permit progression to adenocarcinoma, result in difficulties predicting which tumors are high risk and will progress to invasive disease. In this review, we summarize the current management guidelines and describe ongoing efforts to more clearly stratify IPMNs by risk of malignancy and identify IPMNs with malignant potential or ongoing malignant transformation.

Thirty years of experience with intraductal papillary mucinous neoplasm of the pancreas: from discovery to international consensus

BACKGROUND

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is characterized by intraductal papillary proliferation of mucin-producing epithelial cells that exhibit various degrees of dysplasia. IPMN is classified as the main duct type (MD-IPMN) and the branch duct type (BD-IPMN) according to the location of involvement, and into four histological subtypes (gastric, intestinal, pancreatobiliary, and oncocytic) according to the histomorphological and immunohistochemical characteristics. Mucin core protein expression correlates with the biological behavior and prognosis of the tumor. DNA analysis has shown that IPMN is associated with a number of gene mutations, but the roles of many of these mutations require further investigation. Most patients with MD-IPMN undergo tumor resection. Patients with BD-IPMN who do not undergo resection may develop malignant change, and concomitant separate pancreatic cancer occurs in 2-10% of patients with IPMN. Patients with a strong family history may develop multiple BD-IPMNs as well as concomitant pancreatic cancer. Malignant changes are relatively easy to detect, especially by endoscopic ultrasonography (EUS), but the optimal surveillance protocol is currently unclear.

KEY MESSAGES

The 2012 guidelines for the management of IPMN recommend that patients with 'high-risk stigmata' (obstructive jaundice, enhanced solid component, and main pancreatic duct size ≥10 mm) should undergo resection. Patients with 'worrisome features' (cyst size ≥3 cm, thickened enhanced cyst walls, non-enhanced mural nodules, main pancreatic duct size 5-9 mm, abrupt change in main pancreatic duct caliber with distal pancreatic atrophy, lymphadenopathy, and clinical acute pancreatitis) should be evaluated by EUS. EUS is a more sensitive test than computed tomography or magnetic resonance imaging for the early detection of malignancy.

CONCLUSIONS

Most patients with MD-IPMN should undergo tumor resection. Patients with BD-IPMN who do not undergo resection should undergo careful surveillance including EUS for the early detection of malignant change and separate pancreatic cancer.

Repeating regional acute pancreatitis in the head of the pancreas caused by intraductal papillary mucinous neoplasms in the tail: report of a case

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is a distinct entity characterized by papillary proliferations of mucin-producing epithelial cells with excessive mucin production and cystic dilatation of the pancreatic ducts. The clinical presentation often involves recurrent episodes of pancreatitis associated with the temporal obstruction of the main pancreatic duct caused by the hypersecretion of mucin. We herein describe a case in which the patient repeatedly experienced the occurrence of idiopathic acute pancreatitis in the head of the pancreas over a 9-year period, and who was ultimately was cured by distal pancreatectomy for IPMNs in the pancreatic tail. This case illustrates the potential pitfalls in the diagnosis of IPMNs owing to a discrepancy between the site of pancreatitis and that of the IPMN. The possible mechanisms linking acute pancreatitis with the formation of IPMNs are also reviewed.

Nonprevention of post-endoscopic retrograde cholangiopancreatographic pancreatitis by pancreatic stent after aspiration of pure pancreatic juice in patients with intraductal papillary mucinous neoplasms of the pancreas

OBJECTIVES

The objective of this study was to evaluate the efficacy of a pancreatic stent regarding the prevention of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis after aspiration of pure pancreatic juice in patients with intraductal papillary mucinous neoplasms.

METHODS

A retrospective study was made to assess the outcome in 121 consecutive patients with intraductal papillary mucinous neoplasms who underwent endoscopic aspiration of pure pancreatic juice for cytologic examination between July 2001 and October 2007. From July 2001 to March 2004, 58 patients did not undergo pancreatic stent insertion (the no-stent [nS] group). The remaining 63 patients did undergo stent insertion (stent [S] group).

RESULTS

The overall incidences of post-ERCP pancreatitis was 11 (9.1%). The incidences of post-ERCP pancreatitis in the S and nS groups were 8 (12.7%) and 3 (5.2%; P = 0.21), respectively. In the male patients and the patients with a smaller diameter of the main pancreatic ducts, post-ERCP pancreatitis was seen more frequently in those in the S group (13% and 21%, respectively) than in those in the nS group (0% and 0%, respectively; P = 0.04, 0.03).

CONCLUSIONS

The pancreatic stent did not seem to decrease the incidence of post-ERCP pancreatitis in patients with intraductal papillary mucinous neoplasms. Furthermore, the pancreatic stent seems to be potentially detrimental in male patients and in patients with small-diameter main pancreatic ducts.

[Precursors of Pancreatic cancer: Intraepithelial Neoplasia (PanIN) and Intraductal Papillary Mucinous Neoplasms (IPMN)]

Pancreatic Intraepithelial Neoplasia (PanIN1-3) and Intraductal Papillary Mucinous Neoplasms (IPMN) putative precursors of and associated to pancreatic cancer represent a distinct, however pathologically heterogenous entity. Recently a new classification and nomenclature was established. We review the clinicopathologic and cytogenetic characteristics of PanIN and IPMN highlighting the nonaggressive biological behavior of intraepithelial and intraductal neoplasms which, in part explain their favorable prognosis.

Pancreatobiliary fistula associated with an intraductal papillary-mucinous pancreatic neoplasm manifesting as obstructive jaundice: report of a case

We report a pancreatobiliary fistula caused by an intraductal papillary-mucinous pancreatic neoplasm (IPMN), manifesting as obstructive jaundice. Computed tomography showed dilatation of the bile duct and main pancreatic duct, with multiple cystic masses in the head of the pancreas. Endoscopic retrograde pancreatocholangiography showed a patulous papilla with mucin secretion. Contrast enhancement outlined amorphous material obstructing the lower part of the common hepatic duct. Pancreatogram and magnetic resonance cholangiopancreatography showed diffuse dilatation of the main pancreatic duct and side branches without communication with the adjacent organs or duct. We performed pancreaticoduodenectomy for IPMN of the pancreatic head and a tumor-like lesion in the lower common bile duct (CBD). Macroscopically, impacted thick mucus protruded into the CBD from the pancreas via a pancreatobiliary fistula. Histologic examination revealed a pancreatobiliary fistula caused by intraductal papillary-mucinous carcinoma of the pancreas with mucin hypersecretion, an adenoma without interstitial infiltration, and isolated implantation of an IPMN in the bile duct mucosa around the fistula.

Precursor lesions of pancreatic cancer: molecular pathology and clinical implications

BACKGROUND

Pancreatic cancer is a lethal disease, with near uniform 5-year mortality rates. The key to improving survival of pancreatic cancer rests upon early detection of this neoplasm at a resectable, and hence potentially curable, stage.

METHODS

We review the current state of the literature vis-à-vis the three common precursor lesions of pancreatic adenocarcinoma: pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and mucinous cystic neoplasm. We also discuss two clinical scenarios of emerging importance, namely asymptomatic pancreatic cysts ('pancreatic incidentalomas') and the significance of precursor lesions in familial pancreatic cancer kindreds.

RESULTS

Pancreatic intraepithelial neoplasias are the microscopic precursor lesions of pancreatic adenocarcinomas, while intraductal papillary mucinous neoplasms and mucinous cystic neoplasms are macroscopic, cystic precursor lesions. All three noninvasive entities demonstrate a multistep morphologic and genetic progression that culminates in frank invasive adenocarcinoma. Despite these commonalities, each precursor lesion harbors a unique repertoire of clinicopathologic and genetic characteristics that has an impact on natural history and prognosis of these lesions. Due to improvements in radiological techniques, asymptomatic pancreatic cysts are being increasingly discovered in the general population; intraductal papillary mucinous neoplasms and mucinous cystic neoplasms are the most common underlying histology in resected incidentalomas of the pancreas. Pancreatic asymptomatic cysts present an enormous challenge in terms of accurate diagnosis and management stratification. Incorporating molecular signatures of cystic precursor lesions into the diagnostic algorithm will likely become a standard of care for asymptomatic pancreatic cysts. High-risk individuals from familial pancreatic cancer kindreds are another group of individuals where knowledge of precursor lesions has had a therapeutic impact; sensitive imaging technologies have enabled the identification and subsequent resection of pancreatic cancer precursors in these high-risk individuals, preventing the progression to invasive cancer.

CONCLUSIONS

Precursor lesions of pancreatic adenocarcinomas represent a unique opportunity for diagnosis and intervention for a malignancy with near uniform lethality. Further studies on these precursors will enable the development of rational early detection and therapeutic strategies in order to ameliorate pancreatic cancer survival.

Solid and papillary epithelial neoplasm of the pancreas

Solid and papillary epithelial (SPEN) is an uncommon pancreatic tumor often seen in young females. Although most of these neoplasms have a benign course, SPEN do have malignant potential. Treatment is surgical which is usually feasible either via enucleation or more radical procedures. Below we discuss diagnosis, treatment, and prognosis in detail.

Histopathological study of intraductal papillary mucinous tumor of the pancreas: special reference to the roles of Survivin and p53 in tumorigenesis of IPMT

AIM

In this study, we investigated the tissue expression of Survivin, p53, and Bcl-2 in intraductal papillary-mucinous tumor (IPMT) of the pancreas to identify their roles in tumorigenesis of IPMT, and examined their correlations with tumor cell apoptosis and proliferation in IPMT. The diagnostic values of the expression of Survivin, p53, and Bcl-2 and the apoptotic index (AI) and Ki-67 labeling index (Ki-67 LI) in IPMT were also examined.

METHODS

Twenty-two lesions from 17 patients with IPMT, including 12 benign (IPMT Adenoma) and 10 malignant (IPMT Carcinoma In Situ [CIS] (n = 4) and Invasive IPMT (n = 6) lesions, were immunostained for Survivin, p53, Bcl-2 and Ki-67. The apoptotic cells were detected by the Apop Tag(R) In Situ Oligo Ligation (ISOL) method.

RESULTS

The immunoreactivities for Survivin and p53 significantly increased in the transition from IPMT Adenoma to IPMT CIS (p < 0.05 for both). This transition was associated with a significant decrease in tumor cell apoptosis ( p < 0.001). The expression of Survivin was significantly associated with AI in IPMT ( p < 0.01), but not with Ki-67 LI. The expressions of Survivin and p53, and AI and Ki-67 LI were also significantly different between benign IPMT and malignant IPMT. Bcl-2 was not expressed in IPMT.

CONCLUSION

These results suggest that Survivin and p53 may play important roles in the transition from IPMT Adenoma to IPMT CIS. This transition is accompanied by a significant decrease in tumor cell apoptosis. Survivin is significantly associated with the change in AI in IPMT. The immunohistochemical detection of Survivin and p53 as well as the determination of the AI and Ki-67 LI have useful roles in the diagnosis of IPMT.

Intraductal papillary-mucinous neoplasms of the pancreas: an analysis of in situ and invasive carcinomas in 28 patients

BACKGROUND

Intraductal papillary-mucinous neoplasms (IPMNs) of the pancreas are intraductal tumors with variable amounts of papilla formation, mucin production, and cytoarchitectural atypia. Associated invasive carcinomas, reported to occur in up to 30% of patients, often are mucinous and clinically indolent.

METHODS

The clinical and pathologic features of 28 IPMNs resected at Memorial Sloan-Kettering Cancer Center between 1983 and 1997 were reviewed.

RESULTS

There were 16 females and 12 males with a mean age of 68 years (range, 44-79 years) and a mean tumor size of 4.5 cm (range, 1.5-11.0 cm). The head of the gland was the predominant tumor site (89%). Abdominal pain, weight loss, and acholic stool were the most common symptoms at presentation. According to histology, two types of papillae were identified: intestinal (22 patients) and pancreatobiliary (6 patients). In the intraductal component, cytologic atypia was minimal (i.e., intraductal papillary-mucinous [IPM] adenoma) in 2 patients and moderate (IPM borderline tumor) in 5 patients, and severe atypia (IPM carcinoma in situ) was seen at least focally in 21 patients. In addition, invasive carcinoma was identified in 15 patients (53%), 4 of whom had only microscopic foci. Invasive carcinoma was of the mucinous type (colloid) in six patients and of the tubular type (conventional ductal adenocarcinoma) in nine patients. At a median follow-up of 35 months, four patients died of disease; two of these patients had only borderline atypia with no identified in situ or invasive carcinoma in the sections submitted. Eighteen patients had no evidence of disease, 1 patient was alive with recurrent disease, and 5 patients died of other causes. The actuarial 5-year disease free survival rate was 78%. Of the 14 patients with invasive carcinoma, 5 of 6 patients with colloid type tumors were free of tumor at a mean of 55 months. Of the patients with tubular type invasive carcinoma, two patients died of their disease (at 4 years and 7 years), three patients died of other causes, and four patients were alive (three were free of disease, and one experienced disease recurrence) at an average follow-up of 7.5 years.

CONCLUSIONS

Two distinct patterns of intraductal papillae are seen in patients with IPMNs: intestinal and pancreatobiliary. Both in situ and invasive carcinoma may be encountered more commonly than previously recognized. Tubular type invasive carcinomas occur as well as mucinous type (colloid) carcinomas. Although the neoplasms are less aggressive as a group than conventional pancreatic ductal adenocarcinoma, patients with IPMNs may pursue a deadly course, even in the absence of identifiable invasive carcinoma. Conversely, patients with tubular type invasive carcinoma arising in the background of IPMN may follow a more favorable course than patients with conventional ductal adenocarcinoma without IPMN, emphasizing the importance of recognizing the IPMN component in patients with pancreatic adenocarcinoma.

Almost all infiltrating colloid carcinomas of the pancreas and periampullary region arise from in situ papillary neoplasms: a study of 39 cases

Colloid carcinomas of organs such as the breast, colon, and prostate have been well characterized. However, up until now there have been only a few studies of colloid carcinomas of the pancreas and periampullary region, and the number of colloid carcinomas in these studies has been limited. A search of our files revealed 39 resections for pancreatic and periampullary carcinomas with colloid differentiation. All neoplasms were extensively sampled. "Carcinomas with colloid differentiation" were defined as tumors associated with abundant extracellular mucin containing free-floating mucinous epithelial cells. Cases with >50% colloid differentiation were classified as "colloid carcinomas," whereas those with less were termed "carcinomas with focal colloid features." Cases with no colloid differentiation at all were designated "carcinomas without colloid differentiation." Of the 39 carcinomas, 31 were colloid carcinomas, and eight were carcinomas with focal colloid features. Twenty-seven were centered in the pancreas, seven were in the duodenum, and five were in the ampulla of Vater. Remarkably, 38 of the 39 carcinomas (97%) arose in association with an intraductal papillary mucinous neoplasm or a tubular/tubulovillous adenoma. Of the patients with colloid carcinomas, the 2-and 5-year actuarial survival rates were 69% and 29%, respectively. There was no significant difference in survival rates between patients with colloid carcinomas and patients with adenocarcinomas without colloid differentiation, whether or not the latter arose in association with intraductal papillary mucinous neoplasms or tubular/tubulovillous adenomas. In a multivariate model colloid differentiation was not an independent predictor of patient survival, while other factors such as tumor location, perineural invasion, vascular invasion, and margin status after resection independently influenced patient survival. Most colloid carcinomas of the pancreas and periampullary region arise in association with a well-defined in situ papillary neoplasm. The diagnosis of a pancreatic or periampullary colloid carcinoma should encourage the pathologist to search for an associated low-grade in situ component. In addition, colloid carcinomas of the pancreas and periampullary region do not necessarily have a better prognosis than carcinomas without colloid differentiation. Instead, other factors such as tumor location, perineural invasion, vascular invasion, and margin status after resection are far more important.

Surveillance of pre-malignant disease of the pancreatico-biliary system

Technical advancements in ultrasonography, contrast-enhanced computed tomography and magnetic resonance imaging, as well as the wider availability of these ultramodern imaging techniques, have resulted in the early detection and a better classification of various asymptomatic and symptomatic pancreatico-biliary lesions. Pre-malignant biliary and pancreatic lesions are rare disorders, and no clear data are available to define their malignant potential. Because of the lack of controlled epidemiological data, the time span for malignant transformation and its frequency cannot be defined in the majority of these lesions. Adenomyomatosis of the gallbladder and gallbladder polyps larger than 10 mm should be treated by cholecystectomy even in asymptomatic patients because of an increased risk of malignant transformation. Chronic cholangitis, primary sclerosing cholangitis and choledochal cysts are also pre-malignant conditions. The timing of surgery, once it is advised for a pre-malignant condition that is still benign, should, however, be individualized to the particular patient situation. In patients with chronic pancreatitis, surgery may be indicated for disease-related complications. In as much as chronic pancreatitis predisposes to a higher risk of pancreatic cancer, any suspicion of malignancy should warrant a surgical exploration. Intraductal papillary tumours and mucin-producing pancreatic tumours are other pre-malignant pancreatic lesions whose malignant potential cannot be precisely determined pre-operatively. They should be resected in situations where there is a high degree of suspicion even without a clear objective diagnosis. In conclusion, pre-malignant hepato-biliary and pancreatic lesions of uncertain pathology should undergo early resection in view of treatment limitations and the dismal prognosis of established cancers. While hepato-biliary and pancreatic surgery is nowadays performed in specialized centres, with a low post-operative morbidity and mortality, it is equally important to understand that observation alone with regular computed tomography or magnetic resonance imaging control can no longer be recommended in the management of these lesions.

Preoperative diagnosis of intraductal papillary-mucinous tumors of the pancreas with attention to telomerase activity

BACKGROUND

It has been reported that, in patients with intraductal papillary-mucinous tumor (IPMT) of the pancreas, it is difficult to distinguish adenoma from carcinoma preoperatively. Recently, it has also been reported that telomerase activity was detected in many patients with carcinoma. In this report, the authors used the method of telomerase repeat amplification protocol (TRAP) assay on pancreatic juice retrieved by endoscopic retrograde pancreatic juice aspiration (ERP aspiration).

METHODS

Pancreatic juice was collected from 28 patients (13 with intraductal carcinoma and 15 with adenoma) using ERP aspiration at either Hiroshima University Hospital or its affiliated hospitals. Two samples of pancreatic juice were collected from each patient. Each sample was examined by cytology for Papanicolaou staining and TRAP assay.

RESULTS

Four of 13 IPMT patients (31%) with intraductal carcinoma were diagnosed accurately by cytology. Seven of nine patients who were classified with benign tumors by cytologic assessment had tumors that expressed telomerase activity. Overall, 11 of 13 IPMT patients (85%) with intraductal carcinoma were diagnosed correctly by cytology associated with telomerase activity. All of the IPMT patients with adenoma were classified with benign tumors by cytologic assessment, and telomerase activity was not expressed.

CONCLUSIONS

In this study, the authors found that telomerase activity was expressed with a comparatively high probability in intraductal carcinoma. These results suggest that telomerase activity in pancreatic juices may be used as an adjunct to cytologic diagnosis and may aid further in distinguishing between benign IPMT and malignant IPMT of the pancreas preoperatively.

A pancreatic intraductal papillary mucinous tumor causing recurrent acute pancreatitis at the onset of menstrual periods

The unusual case of a young woman with pancreatitis recurring at onset of her menstrual periods is reported. The patient was diagnosed with pancreatic intraductal papillary mucinous tumor (IPMT). The temporal relation of clinical exacerbation of pancreatitis to the menstrual cycle is suggestive of a hormonal-mediated mechanism. The hypothesis of a possible role of progesterone receptors was dismissed with verification of the absence of progesterone and estrogen receptors in the neoplastic tissue. The possible role of activin A or inhibin A in our patient's clinical picture is theorized.

Intraductal mucin-producing tumor of the pancreas: diagnosis by MR cholangiopancreatography

PURPOSE

Our goal was to evaluate the usefulness of MR cholangiopancreatography (MRCP) for intraductal mucin-producing tumor of the pancreas (MPT).

METHOD

Eleven patients with intraductal MPTs (six main duct type; five branch duct type) underwent MRCP. The findings of MRCP were compared with those of endoscopic retrograde cholangiopancreatography (ERCP).

RESULTS

In all of the cases, MRCP could disclose all dilated pancreatic ducts and cysts, some of which were not demonstrated by ERCP. MRCP did not show a signal void of mucin in any of the cases. In the two cases of the main duct type, ERCP showed filling defects of excrescent nodules, which were not seen by MRCP. In the two cases of the main duct type, nodules were seen more clearly by ERCP than by MRCP.

CONCLUSION

MRCP and ERCP are complementary imaging modalities for intraductal MPT.

Detection of K-ras gene mutations at codon 12 in the pancreatic juice of patients with intraductal papillary mucinous tumors of the pancreas

BACKGROUND

The authors previously found specific mutations of the K-ras gene at codon 12 in the pancreatic juice of 67% of patients (6 of 9) with pancreatic ductal carcinoma, and the detection of these mutations was useful for diagnosis. This study was performed to detect and evaluate K-ras mutations in pancreatic juice from patients with intraductal papillary mucinous tumor of the pancreas, which is considered a low grade malignancy. The results were interpreted from the viewpoint of clinical significance.

METHODS

K-ras mutations were examined using seminested polymerase chain reaction analysis combined with restriction enzyme digestion, followed by nonradioisotopic single strand DNA conformation polymorphism.

RESULTS

Twelve of thirteen cases (92%) of intraductal papillary mucinous tumor of the pancreas, confirmed histologically (9 adenomas and 4 carcinomas), and 26 of 43 cases (60%) of ductal carcinoma showed specific K-ras gene mutations in the pancreatic juice. Furthermore, 4 of 22 patients (18%) with chronic pancreatitis, followed for more than 1 year without a sign of pancreatic tumor, showed K-ras mutations. In contrast, no mutations of the K-ras gene were detected in the pancreatic juice from 28 normal controls.

CONCLUSIONS

K-ras mutations were found in the pancreatic juice of all but one patient with intraductal papillary mucinous tumor of the pancreas, but they were not useful for distinguishing carcinoma from adenoma. The authors concluded that K-ras mutations are not a specific marker for pancreatic neoplasms because similar mutations were detected in the pancreatic juice from patients with chronic pancreatitis. At the present time, the detection of K-ras mutations in pancreatic juice should be used clinically as an adjunct diagnostic modality for pancreatic diseases.

Detection of K-ras gene mutations at codon 12 in the pancreatic juice of patients with intraductal papillary mucinous tumors of the pancreas

BACKGROUND

The authors previously found specific mutations of the K-ras gene at codon 12 in the pancreatic juice of 67% of patients (6 of 9) with pancreatic ductal carcinoma, and the detection of these mutations was useful for diagnosis. This study was performed to detect and evaluate K-ras mutations in pancreatic juice from patients with intraductal papillary mucinous tumor of the pancreas, which is considered a low grade malignancy. The results were interpreted from the viewpoint of clinical significance.

METHODS

K-ras mutations were examined using seminested polymerase chain reaction analysis combined with restriction enzyme digestion, followed by nonradioisotopic single strand DNA conformation polymorphism.

RESULTS

Twelve of thirteen cases (92%) of intraductal papillary mucinous tumor of the pancreas, confirmed histologically (9 adenomas and 4 carcinomas), and 26 of 43 cases (60%) of ductal carcinoma showed specific K-ras gene mutations in the pancreatic juice. Furthermore, 4 of 22 patients (18%) with chronic pancreatitis, followed for more than 1 year without a sign of pancreatic tumor, showed K-ras mutations. In contrast, no mutations of the K-ras gene were detected in the pancreatic juice from 28 normal controls.

CONCLUSIONS

K-ras mutations were found in the pancreatic juice of all but one patient with intraductal papillary mucinous tumor of the pancreas, but they were not useful for distinguishing carcinoma from adenoma. The authors concluded that K-ras mutations are not a specific marker for pancreatic neoplasms because similar mutations were detected in the pancreatic juice from patients with chronic pancreatitis. At the present time, the detection of K-ras mutations in pancreatic juice should be used clinically as an adjunct diagnostic modality for pancreatic diseases.

Expression of oncogene products, anti-oncogene products and oncofetal antigens in intraductal papillary-mucinous neoplasm of the pancreas

A few previous studies have demonstrated the expression or mutations of oncogenes and anti-oncogenes as well as that of oncofetal antigens in intraductal papillary-mucinous neoplasm of the pancreas. In this study, we have investigated the immunohistochemical expression of oncogene (ras and c-erbB-2) and anti-oncogene (p53 and retinoblastoma [Rb]) products and oncofetal antigens (CEA, CA19-9 and DUPAN-2) in nine such tumours of the pancreas. In normal pancreas (5 cases), the Rb gene product and CA19-9 were expressed in all cases, while ras and c-erbB-2 gene products, p53 protein, CEA and DUPAN-2 were not expressed. In intraductal papillary-mucinous tumours (n = 9), ras, c-erbB-2, p53 and Rb gene products were present in 4/9 (44%), 7/9 (78%), 0.9 (0%) and 6/9 (67%) cases, respectively. CEA, CA19-9 and DUPAN-2 were expressed in 8/9 (89%), 9/9 (100%) and 2/9 (22%) cases respectively. In invasive ductal adenocarcinoma of the pancrease (7 cases), ras, c-erbB-2, p53 and Rb gene products were expressed in 3/7 (43%), 6/7 (86%), 2/7 (29%) and 3/& (43%) cases respectively. CEA, CA19-9 and DUPAN-2 were expressed in 7/7 (100%), 7/7 (100%) and 6/7 (86%) cases, respectively. The extent and intensity of the expression of these antigens was greater in invasive ductal adenocarcinomas. These data suggest that activation of ras and c-erbB-2 oncogenes and inactivation of Rb anti-oncogene may contribute to the development and progression of intraductal papillary-mucinous tumours of the pancreas and that there is neo-expression of CEA and DUPAN-2 during the development and progression of these tumours.

Intraductal oncocytic papillary neoplasms of the pancreas

We describe the clinical and pathologic features of 11 intraductal oncocytic papillary neoplasms of the pancreas, a hitherto unrecognized tumor. The patients were six men and five women, and most of the tumors were in the head (head: body/tail = 8:3). The mean patient age was 62 (range, 39-78), and the average tumor size was 6 cm. Grossly the tumors exhibited mucin-filled cysts containing nodular papillary projections. Dilated ducts communicating with the main tumor were sometimes noted. Microscopically the cystic structures appeared to represent dilated ducts containing intraductal tumor. The tumors were characterized by variably complex, arborizing papillary structures. The papillae had thin, delicate fibrovascular cores with focal myxoid changes and were lined by stratified oncocytic cells. Goblet cells and intra-epithelial mucin-containing lumina were present, the latter resulting in a characteristic cribriform pattern. The exuberance of the epithelial proliferation varied from case to case and between different regions within individual tumors; solid sheets of cells were often identified. Although the degree of cytologic atypia was not generally severe, the complexity of the architecture justified a designation of intraductal oncocytic papillary carcinoma in 10 of the 11 cases. In nine cases the tumor was entirely intraductal; one case exhibited focal microinvasion and another showed widespread invasive carcinoma, the invasive elements appearing cytologically similar to the intraductal papillary components. The oncocytic cells stained positively with phosphotungstic acid hematoxylin and Novelli stains. Immunohistochemically, all cases stained positively for B72.3, and five cases showed focal, weak luminal membrane staining for carcinoembryonic antigen. Ultrastructurally many of the cells were packed with mitochondria, and mucin was also identified. Seven patients were alive and free of tumor from 1 month to 3 years (average, 1 year) after resection. Two patients died postoperatively. The remaining two patients died with no evidence of disease at 2.5 and 5 years, the latter following a recurrence at 2.5 years. We conclude that intraductal oncocytic papillary neoplasm is a distinctive pancreatic tumor that is usually intraductal but may develop invasive carcinoma and should be treated with complete resection.

Mucin-producing neoplasms of the pancreas. Intraductal papillary and mucinous cystic neoplasms

OBJECTIVE

The authors compared the clinicopathologic features of the intraductal papillary and mucinous cystic neoplasms of the pancreas and clarified the similarities as well as the differences between these two tumors. In addition, they reviewed 104 cases of the intraductal papillary neoplasm in the English literature to provide a global view of the condition.

SUMMARY BACKGROUND DATA

Controversy about the term and clinicopathologic entity still exist regarding intraductal papillary neoplasm of the pancreas. Currently, with only a few cases of this rare tumor in each report, there continues to be inadequate knowledge available regarding the tumor and methods by which to distinguish it from the mucinous cystic neoplasm.

METHODS

Multiple demographic and clinicopathologic parameters were compared between intraductal papillary and mucinous cystic neoplasms identified from 1985 to 1994 in the Medical Center, Veterans General Hospital--Taipei.

RESULTS

There were four intraductal papillary adenocarcinomas and 10 mucinous cystic neoplasms (8 cystadenocarcinoma and 2 cystadenoma). The sex, age, size, tumor location, and pathologic findings were quite different between these two groups. Clinical presentation of intraductal papillary adenocarcinomas were similar to those of periampullary tumors. The most common presentations of mucinous cystic neoplasm were epigastric pain and abdominal mass. All four intraductal papillary adenocarcinoma showed mucin secretion from a patulous orifice of the ampulla of Vater and filling defects in the dilated main pancreatic duct by endoscopic retrograde cholangiopancreatography (ERCP). Accurate preoperative diagnosis was not easy regarding either group. Serum carbohydrate antigen 19-9 (CA 19-9) was more useful for diagnosis in both groups.

CONCLUSIONS

The intraductal papillary neoplasm is a unique clinical entity but not a variant of mucinous cystic neoplasm in terms of sex, age, size, tumor location, or pathologic picture. The pathognomonic findings of ERCP should lead to diagnosis. Very aggressive surgical procedures should be attempted for these two mucin-producing neoplasms with low-grade malignancy.

Intraductal papillary-mucinous tumours represent a distinct group of pancreatic neoplasms: an investigation of tumour cell differentiation and K-ras, p53 and c-erbB-2 abnormalities in 26 patients

Intraductal papillary growth of mucin producing hypersecreting, columnar cells characterizes a group of rare pancreatic exocrine neoplasms which we propose to call intraductal papillary-mucinous tumors (IPMT). We analysed the histopathology of 26 IPMT in relation to gastro-enteropancreatic marker expression, genetic changes and biology. Four IPMT showing only mild dysplasia were considered to be adenomas. Nine tumours displayed moderate dysplasia and were regarded as borderline. Severe dysplasia-carcinoma in situ changes were found in 13 IPMT which were therefore classified as intraductal carcinomas. Six of these carcinomas were frankly invasive and two of these had lymph node metastases. The invasive component resembled mucinous non-cystic carcinoma in all but one tumour which showed a ductal invasion pattern. Immunohistochemically, an intestinal marker type was found in most carcinomas, while gastric type differentiation prevailed among adenomas or borderline tumours. K-ras mutations (seven at codon 12 and one at codon 13) were found in 31% of IPMT (2 adenomas, 1 borderline, 5 carcinomas). Nuclear p53 overexpression was detected in 31% of IPMT (6 carcinomas and 2 borderline IPMT) and correlated with p53 mutations (one at exon 8 and the other at exon 5) in two carcinomas. p53 abnormalities were unrelated to K-ras mutation. c-erbB-2 overexpression was observed in 65% of IPMT, with various grades of dysplasia. Twenty-two of 24 patients are alive and well after a mean post-operative follow-up of 41 months. Only two patients, both with invasive cancer at the time of surgery, died of tumour disease. It is concluded that pancreatic IPMT encompass neoplasms which, in general, have a favorable prognosis, but are heterogeneous in regard to grade of dysplasia and marker expression. Adenoma, borderline tumour, intraductal carcinoma and invasive carcinoma can be differentiated. p53 changes but not K-ras mutation or c-erbB-2 overexpression are related to the grade of malignancy. Most IPMT differ in histological structure, marker expression and behaviour from ductal adenocarcinoma.