Intraductal papillary mucinous neoplasm: a clinicopathologic review

Acute Pancreatitis Secondary to Newly Diagnosed Intraductal Papillary Mucinous Neoplasm

Acute pancreatitis (AP) is a common gastrointestinal cause of hospital admissions and is prevalent in the United States. AP etiologies include alcohol use, cholelithiasis, hypertriglyceridemia, hypercalcemia, autoimmune phenomena, medications, or idiopathic. Rarely, intraductal papillary mucinous neoplasms can cause AP, as we present in this case report.

Trefoil factor 1 inhibits epithelial-mesenchymal transition of pancreatic intraepithelial neoplasm

The tumor-suppressive role of trefoil factor family (TFF) members in gastric carcinogenesis has been suggested, but their significance and mechanisms in other digestive diseases remain elusive. To clarify the role of TFF1 in pancreatic carcinogenesis, we performed IHC on human samples, transfected siRNA against TFF1 into pancreatic cancer cell lines, and employed mouse models in which PanIN development and loss of TFF1 occur simultaneously. In human samples, the expression of TFF1 was specifically observed in pancreatic intraepithelial neoplasm (PanIN), but was frequently lost in the invasive component of pancreatic ductal adenocarcinoma (PDAC). When the expression of TFF1 was suppressed in vitro, pancreatic cancer cell lines showed enhanced invasive ability and features of epithelial-mesenchymal transition (EMT), including upregulated Snail expression. TFF1 expression was also observed in PanIN lesions of Pdx-1 Cre; LSL-KRASG12D (KC) mice, a model of pancreatic cancer, and loss of TFF1 in these mice resulted in the expansion of PanIN lesions, an EMT phenotype in PanIN cells, and an accumulation of cancer-associated fibroblasts (CAFs), eventually resulting in the development of invasive adenocarcinoma. This study indicates that the acquisition of TFF1 expression is an early event in pancreatic carcinogenesis and that TFF1 might act as a tumor suppressor to prevent EMT and the invasive transformation of PanIN.

Diagnostic performance and imaging features for predicting the malignant potential of intraductal papillary mucinous neoplasm of the pancreas: a comparison of EUS, contrast-enhanced CT and MRI

PURPOSE

To compare diagnostic performance for prediction of malignant potential in IPMNs between EUS, contrast-enhanced CT and MRI.

MATERIALS AND METHODS

76 patients with IPMN (benign = 37, malignant = 39) underwent EUS, contrast-enhanced CT, and MRI. EUS was analyzed based on formal reports and contrast-enhanced CT and MRI were retrospectively analyzed by two radiologists according to the consensus guidelines 2012. Diagnostic performance and imaging features of malignant IPMNs were analyzed using ROC analysis and multivariate analyses.

RESULTS

Diagnostic performance of contrast-enhanced CT (AUC = 0.792 in R1, 0.830 in R2), MRI (AUC = 0.742 in R1, 0.776 in R2), and EUS (AUC = 0.733) for predicting malignant IPMNs were comparable without significant difference (p > 0.05). In multivariable analysis, enhancing solid component in contrast-enhanced CT and MRI and mural nodule in EUS (OR 1.8 in CT, 1.36 in MRI, 1.47 in EUS), MPD diameter ≥ 10 mm (OR 1.3 in CT, 1.4 in MRI, 1.66 in EUS), MPD diameter of 5-9 mm (OR 1.23 in CT, 1.31 in MRI), and thickened septa or wall (OR 1.3 in CT and MRI) were significant variables (p < 0.05). Interobserver agreement of thickened cyst septa or wall (k = 0.579-0.617) and abrupt caliber change of MPD (k = 0.689-0.788) was lower than other variables (k > 0.80).

CONCLUSION

Diagnostic performance of contrast-enhanced CT, MRI, and EUS for predicting malignant IPMNs was comparable with each modalities without significant difference.

Evaluating IPMN and pancreatic carcinoma utilizing quantitative histopathology

Intraductal papillary mucinous neoplasms (IPMN) are pancreatic lesions with uncertain biologic behavior. This study sought objective, accurate prediction tools, through the use of quantitative histopathological signatures of nuclear images, for classifying lesions as chronic pancreatitis (CP), IPMN, or pancreatic carcinoma (PC). Forty-four pancreatic resection patients were retrospectively identified for this study (12 CP; 16 IPMN; 16 PC). Regularized multinomial regression quantitatively classified each specimen as CP, IPMN, or PC in an automated, blinded fashion. Classification certainty was determined by subtracting the smallest classification probability from the largest probability (of the three groups). The certainty function varied from 1.0 (perfectly classified) to 0.0 (random). From each lesion, 180 ± 22 nuclei were imaged. Overall classification accuracy was 89.6% with six unique nuclear features. No CP cases were misclassified, 1/16 IPMN cases were misclassified, and 4/16 PC cases were misclassified. Certainty function was 0.75 ± 0.16 for correctly classified lesions and 0.47 ± 0.10 for incorrectly classified lesions (P = 0.0005). Uncertainty was identified in four of the five misclassified lesions. Quantitative histopathology provides a robust, novel method to distinguish among CP, IPMN, and PC with a quantitative measure of uncertainty. This may be useful when there is uncertainty in diagnosis.

Intraductal papillary mucinous neoplasms of the pancreas: evaluation of malignant potential and surgical resectability by using MR imaging with MR cholangiography

PURPOSE

To evaluate the diagnostic performance of magnetic resonance (MR) imaging with MR cholangiopancreatography (MRCP) in determining the malignant potential and surgical resectability of pancreas intraductal papillary mucinous neoplasms (IPMNs).

MATERIALS AND METHODS

Institutional review board approval was obtained, and the requirement for informed consent was waived. Ninety-eight patients with pathologically proved pancreas IPMNs who underwent MR imaging with MRCP comprised the study population. MR images were analyzed for findings suggestive of high-risk stigmata or worrisome features, as proposed by the international consensus guidelines 2012. Interobserver agreement between two experienced observers (observers 1 and 2) and one inexperienced observer (observer 3) was assessed. Diagnostic performance of MR imaging in the evaluation of the malignant potential and surgical resectability of IPMNs was analyzed in these three observers by using receiver operating curve analysis.

RESULTS

MR imaging with MRCP showed sensitivity of 83% (35/42), 79% (33/42), and 90% (38/42); specificity of 80% (41/51), 51% (26/51), and 24% (12/51); and accuracy of 82% (76/93), 63% (59/93), and 54% (50/93) for observers 1, 2, and 3, respectively, in the evaluation of the malignant potential of pancreas IPMNs when at least one worrisome feature was present. Interobserver agreement in the detection of intramural nodules (κ = 0.349-0.574), enhanced solid components (κ = 0.318-0.574), and measurement of main pancreatic duct diameter (intraclass correlation coefficient = 0.9477) was fair to high. The respective sensitivity, specificity, and accuracy in determination of surgical resectability were 95% (81/85), 99% (84/85), and 88% (75/85); 69% (9/13), 69% (9/13), and 54% (7/13); and 92% (90/98), 95% (93/98), and 84% (82/98) for observers 1, 2, and 3.

CONCLUSION

MR imaging with MRCP is a useful modality in the evaluation of the malignant potential and resectability of IPMNs, with high sensitivity and moderate specificity in the experienced radiologists but relatively low specificity in the inexperienced radiology trainee.

Autoimmune pancreatitis type-1 associated with intraduct papillary mucinous neoplasm: report of two cases

Chronic pancreatitis lesions usually embrace both intraduct papillary mucinous neoplasm (IPMN) and pancreatic ductal adenocarcinoma (PDAC). Patients at genetically-determined high risk of PDAC often harbor IPMN and/or chronic pancreatitis, suggesting IPMN, chronic pancreatitis and PDAC may share pathogenetic mechanisms. Chronic autoimmune pancreatitis (AIP) may also herald PDAC. Concurrent IPMN and AIP have been reported in few patients. Here we describe two patients with IPMN who developed type-1 AIP fulfilling the Honolulu and Boston diagnostic criteria. AIP diffusively affected the whole pancreas, as well as peripancreatic lymph nodes and the gallbladder. Previous pancreatic resection of focal IPMN did not show features of AIP. One of the patients carried a CFTR class-I mutation. Of notice, serum IgG4 levels gradually decreased to normal values after IPMN excision. Common risk factors to IPMN and AIP may facilitate its coincidental generation.

Visualization of the leakage of pancreatic juice using a chymotrypsin-activated fluorescent probe

BACKGROUND

Pancreatic fistula (PF) remains the most serious complication after digestive surgery. It is difficult to prevent because of the inability to visualize the leakage of pancreatic juice during surgery or to evaluate the protease activity of leaked fluid, which is responsible for PF formation.

METHODS

The fluorescence intensities of a chymotrypsin probe (glutaryl-phenylalanine [corrected] hydroxymethyl rhodamine green with added trypsin) in pancreatic juice and in intestinal or abdominal fluids drained after pancreatic resection were evaluated. The chymotrypsin probe was sprayed on to filter papers that had been placed on the resected pancreatic stump in patients undergoing pancreaticoduodenectomy or central pancreatectomy. The ability of this technique to visualize the leakage of pancreatic juice and predict postoperative PF formation was assessed.

RESULTS

The fluorescence intensity of the chymotrypsin probe in 76 fluid samples correlated positively with amylase levels (r(s) = 0.678, P < 0.001). The fluorescence patterns of the pancreatic stump were classified grossly into the three types: duct (fluorescence signal visualized only on the stump of the main pancreatic duct, 16 patients), diffuse (ductal stump and surrounding pancreatic parenchyma, 7) and negative (no fluorescence signal, 7). Symptomatic PFs developed in 13 of 23 patients with duct- or diffuse-type fluorescence, but in none of the seven patients with negative-type fluorescence (P = 0.008).

CONCLUSION

The chymotrypsin probe enabled determination of the protease activity in drained pancreatic fluid samples and allowed real-time visualization of pancreatic juice leakage during surgery.

Clinicopathological subclassification of biliary cystic tumors: Report of 4 cases with a review of the literature

Biliary cystic tumors are rare hepatic neoplasms, and knowledge regarding the origin and pathology of these tumors remains vague. They should be analyzed in more detail. In our institution, 4 biliary cystic tumor surgeries were performed between December 1999 and March 2010. Pathological evaluation of resected specimens was performed to evaluate the characteristics of the intracystic epithelium and to determine the presence or absence of interstitial infiltrate, ovarian mesenchymal stroma (OMS), luminal communication between the cystic tumor and the bile duct, and mucin (MUC) protein expression. We evaluated the following 4 cases: case 1, a 21-year-old woman with a biliary cystadenoma who underwent extended right hepatectomy; case 2, a 39-year-old woman with a biliary cystadenoma who underwent left hepatectomy; case 3, an 80-year-old man with a biliary cystadenoma who underwent left hepatectomy; and case 4, a 61-year-old man with a biliary cystadenocarcinoma revealing papillary proliferation of atypical epithelium and interstitial infiltrates who underwent left hepatectomy. Case 3 had papillary proliferation of the intracystic atypical epithelium but showed interstitial infiltrates. Luminal communication with the bile duct, centrally or peripherally, was found in all 4 cases. Only case 2 showed OMS. Immunohistochemical staining revealed the following findings: cases 1 and 2, MUC1-/MUC2-; case 3, MUC1+/MUC2-; and case 4, MUC1+/MUC2+. It is important to gather information on more cases of biliary cystic tumors because atypical cases were observed, where both OMS and luminal communication with the bile duct were present or absent.

Added value of diffusion-weighted imaging to MR cholangiopancreatography with unenhanced mr imaging for predicting malignancy or invasiveness of intraductal papillary mucinous neoplasm of the pancreas

PURPOSE

To investigate the added value of diffusion-weighted imaging (DWI) to magnetic resonance cholangiopancreatography (MRCP) with unenhanced MR imaging for predicting the malignancy or invasiveness of intraductal papillary mucinous neoplasms (IPMNs).

MATERIALS AND METHODS

Following Institutional Review Board (IRB) approval, this retrospective study included 52 patients with surgically resected IPMNs and who underwent MRCP, unenhanced MRI, and DWI. Three blinded radiologists evaluated the two image sets, ie, MRCP with unenhanced MR images vs. the combined set with MRCP, unenhanced MR images, and DWI, and scored their confidence for malignancy or for invasiveness of IPMNs. The mean apparent diffusion coefficient (ADC) values of benign IPMNs and of intraductal mucinous carcinomas (IPMCs) were compared. The diagnostic accuracy was calculated using receiver operating characteristic (ROC) curve analysis.

RESULTS

The mean ADC of malignant IPMNs (2.05 ± 0.66 × 10(-3) mm(2) /sec) was significantly lower than that of benign IPMNs (2.95 ± 0.32 × 10(-3) mm(2) /sec, P < 0.0001). Invasive IPMCs (1.51 ± 0.32 × 10(-3) mm(2) /sec) showed significantly lower ADC than that of noninvasive IPMCs (2.67 ± 0.23 × 10(-3) mm(2) /sec, P = 0.0003). The area of diffusion restriction was more frequently seen in malignant IPMNs than in benign IPMNs (P < 0.00001). The addition of DWI to MRCP with unenhanced MRI did not show a significant improvement for predicting malignant IPMN (P> 0.05), but resulted in a tendency to improve the diagnostic accuracy for the prediction of invasive IPMN in two observers (P = 0.072, P = 0.085).

CONCLUSION

The addition of DWI to MRCP with unenhanced MRI may improve the diagnosis of malignant IPMN and further increase the prediction of invasive IPMC.

The incidental cystic pancreas mass: a practical approach

Technical advances in cross-sectional imaging have led to the discovery of incidental cystic pancreatic lesions in the oncology and non-oncology population that in the past remained undetected. These lesions have created a diagnostic and management dilemma for both clinicians and radiologists: should these lesions be ignored, watched, aspirated, or removed? In this review, recommendations concerning the assessment of the more common pancreatic cystic incidental lesions are presented.

Intraductal papillary mucinous neoplasms: does a family history of pancreatic cancer matter?

BACKGROUND/OBJECTIVES

The purpose of this study is to compare surgically resected intraductal papillary mucinous neoplasms (IPMNs) in patients with and without a family history of pancreatic cancer to gain insight into differences that may suggest the need for differential management.

METHODS

A retrospective review of patients who underwent resection of an IPMN at the Massachusetts General Hospital (1990-2011) was conducted. Three hundred and twenty-four patients of whom 45 (13.9%) had a family history of pancreatic cancer were identified. Patients with (PFH) and without (NFH) a family history of pancreatic cancer were compared.

RESULTS

There were no differences in demographic characteristics between groups. Extra-pancreatic malignancies diagnosed prior to the IPMN were more common in those with a PFH (35.6% vs 20.1%, p = 0.03). There were no differences in IPMN characteristics between groups including no difference in the presence of invasive disease (p = 0.55). Concurrent pancreatic ductal adenocarcinomas were more common in those with a PFH (11.1% vs 2.9%, p = 0.02). The survival in the PFH group was marginally lower than the NFH group, a difference found to be attributable to the higher prevalence of extra-pancreatic malignancies.

CONCLUSION

Characteristics of surgically resected IPMNs are not different between patients with and without a family history of pancreatic cancer. Most importantly, the incidence of invasive disease is not different, suggesting that these lesions may not be more aggressive when they occur in the presence of a family history of pancreatic cancer.

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.

Development of pancreatic ductal adenocarcinoma associated with intraductal papillary mucinous neoplasia

We retrospectively investigated the incidence of pancreatic ductal adenocarcinoma among patients with intraductal papillary mucinous neoplasms of the pancreas. Based on imaging in 195 such patients, we chose surgery as initial treatment for 54, and periodic evaluation over 6 to 192 months (mean, 52) for 141. In 6 of the 141 patients observed for intraductal papillary mucinous neoplasm (4.2%), pancreatic ductal adenocarcinoma developed. Further, careful monitoring for cancer occurrence in the remnant pancreas proved essential in the surgical resection group; 2 of 26 patients (7.7%) subsequently developed pancreatic ductal adenocarcinoma in the remnant pancreas, at 41 months and 137 months after surgery. Serial observation of patients with intraductal papillary mucinous neoplasms by contrast-enhanced computed tomography or magnetic resonance cholangiopancreatography therefore is critical, whether or not surgical treatment initially was performed.

Frequency of subtypes of biliary intraductal papillary mucinous neoplasm and their MUC1, MUC2, and DPC4 expression patterns differ from pancreatic intraductal papillary mucinous neoplasm

BACKGROUND

Biliary intraductal papillary mucinous neoplasm (B-IPMN) has been proposed as a unique clinicopathologic disease with distinct histopathologic features, although wide acceptance remains controversial. A recent consensus conference classified pancreatic IPMN (P-IPMN) into 4 subtypes (ie, gastric, intestinal, pancreatobiliary, oncocytic) based on morphologic appearance and mucin (MUC) staining properties. The aim of this study was to determine whether B-IPMN has similar histopathologic and immunologic subtypes to P-IPMN.

STUDY DESIGN

Specific immunostaining for MUC1, MUC2, and deleted for pancreas cancer, locus 4 were performed on specimens from 19 patients with a histopathologic diagnosis of B-IPMN. Immunostaining patterns of B-IPMN were correlated with histopathology.

RESULTS

Based on histopathology, the following subtypes of B-IPMN were identified: pancreatobiliary n = 9 (47%), intestinal n = 8 (42%), oncocytic n = 2 (11%), and gastric n = 0 (0%). Pancreatobiliary and oncocytic subtypes of B-IPMN were positive for MUC1 and negative for MUC2, and intestinal subtypes were positive for MUC2 and negative for MUC1. Thirteen of the 19 B-IPMN were associated with invasive carcinoma; loss of deleted for pancreas cancer, locus 4 was found in 6 of 13 invasive components and in 3 of 19 noninvasive components of B-IPMN. Five-year survival for patients with resected B-IPMN and invasive carcinoma was 38%, which is similar to that for resected P-IPMN with invasive carcinoma.

CONCLUSIONS

Histopathologic subtypes and type-specific MUC expression patterns of B-IPMN resemble those of P-IPMN. MUC1 expression and/or absence of MUC2 expression, which correlate with aggressive features of P-IPMN, were found in B-IPMN and correlate with invasive B-IPMN. Loss of deleted for pancreas cancer, locus 4 parallels the findings observed in P-IPMN. These findings provide additional support that B-IPMN is a unique entity with similarities to main duct P-IPMN.

Progress in research of intraductal papillary mucinous neoplasms

Intraductal papillary mucinous neoplasms (IPMNs) represent a spectrum of neoplasms arising from the main pancreatic duct or branch ducts and producing mucin and can be regarded as a type of precancerous lesions. Thanks to improvements in endoscopy and imaging techniques, IPMNs are being diagnosed with increasing frequency. However, there are currently no highly sensitive and specific preoperative criteria available to distinguish benign IPMNs from malignant ones. What's more, the necessity for EUS and ERCP in the diagnosis of IPMNs is still under debate. Here, we review recent advances in research of IPMNs and summarize potential differences between benign and malignant IPMNs.

The use of protein-based biomarkers for the diagnosis of cystic tumors of the pancreas

Proteomics is a powerful method used to identify, characterize, and quantify proteins within biologic samples. Pancreatic cystic neoplasms are a common clinical entity and represent a diagnostic and management challenge due to difficulties in accurately diagnosing cystic lesions with malignant potential and assessing the risk of malignant degeneration. Currently, cytology and other biomarkers in cyst fluid have had limited success in accurately distinguishing both the type of cystic neoplasm and the presence of malignancy. Emerging data suggests that the use of protein-based biomarkers may have greater utility in helping clinicians correctly diagnose the type of cyst and to identify which cystic neoplasms are malignant. Several candidate proteins have been identified within pancreatic cystic neoplasms as potential biomarkers. Future studies will be needed to validate these findings and move these biomarkers into the clinical setting.