Intraductal papillary-mucinous tumor of the pancreas: a historical review of the nomenclature and recent controversy

Intraductal papillary mucinous neoplasm of the pancreas presenting as a giant abdominal mass: A case report

Introduction

Intraductal papillary mucinous neoplasms (IPMNs) constitute a group of rare conditions with a potential for malignant degeneration. The appearance of symptoms should suggest degeneration. This case demonstrates an unusual case of a patient presenting an intestinal type IPMN that was revealed by a large abdominal mass.

Case report

47-year-old woman with a history of hydatid cyst of the liver. The patient was admitted to our hospital for management of large abdominal mass measuring 185 × 128*190 mm. Intra-operative findings showed a voluminous tumor, of approximately 20 cm in all its dimensions, with double solido-cystic component at the expense of the neck and the body of the pancreas. The patient underwent splenopancreatectomy. The histopathological examination confirmed the presence of intestinal type of IPMN of pancreas.

Discussion

Acute pancreatitis is revealed in the majority of cases of IPMNs, related to duct obstruction by secreting mucus plug. IPMNs are rarely the cause of a large abdominal mass. They are cystic lesions of slow evolution, macroscopically visible and rarely macrocystic, unlike serous cystadenoma. The tumor size is a powerful indicator of the malignancy of IPMNs. The current definitive and ideal treatment for main duct and mixed type IMPNs is a surgical resection.

Conclusion

IPMNs are a cystic lesion, rarely revealed by a large mass.

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IPMNs are rarely the cause of a large abdominal mass.

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The tumor size is a powerful indicator of the malignancy of IPMNs.

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The current definitive and ideal treatment for main duct and mixed type IMPNs is surgical resection.

Formation of Pancreatoduodenal Fistula in Intraductal Papillary Mucinous Neoplasm of the Pancreas Decreased the Frequency of Recurrent Pancreatitis

Intraductal papillary mucinous neoplasms (IPMN) of the pancreas are characterized by proliferation of mucin-secreting cells in the main pancreatic duct (PD) or its branches. The secreted thick mucin usually leads to PD obstruction and dilation. A common complication of IPMN is recurrent acute pancreatitis secondary to poor pancreatic fluid drainage, and rarely, pancreatobiliary and pancreatointestinal fistulae. We describe a unique case of IPMN in a 57-year-old male who was referred to our institution for evaluation of recurrent acute pancreatitis. After extensive evaluation, he was diagnosed with main duct IPMN. Intraductal PD biopsy revealed intestinal type IPMN with intermediate grade dysplasia. Patient was managed clinically by large caliber (10 French) PD stenting which eliminated his recurrent acute pancreatitis. The patient was initially referred for pancreatic resection; however, surgery was aborted and evaluated to be high risk with high morbidity secondary to the extensive adhesions between the pancreas and surrounding structures. Patient remained clinically stable for a few years except for an episode of acute pancreatitis that happened after a trial of stent removal. Subsequently, the patient did well after the PD stent was replaced. Recently, repeat abdominal imaging revealed a large pancreatoduodenal fistula which was confirmed on repeat endoscopic retrograde cholangiopancreatography. We were able to perform pancreatoscopy by advancing a regular upper scope through the fistula and into the PD. Interestingly, the fistula relieved the symptoms of obstruction and subsequently decreased the frequency of recurrent pancreatitis episodes with no further episodes at 6 months follow-up. This case highlights the importance of providing adequate PD drainage to reduce the frequency of recurrent acute pancreatitis in the setting of main duct IPMN, especially if the patient is not a surgical candidate. Also, physicians need to monitor for complications such as fistula formation between the pancreas and surrounding structures in the setting of chronic inflammation due to recurrent episodes of pancreatitis. Early identification of a fistula is important for surgical planning. Furthermore, since recent studies suggested a higher incidence of additional primary malignancies in patients with IPMN of the pancreas compared to the general population, patients may be considered for screening for other primary malignancies.

Gene expression changes associated with the progression of intraductal papillary mucinous neoplasms

OBJECTIVES

The diagnosis of high-grade intraductal papillary mucinous neoplasm (IPMN) is difficult to distinguish from low-grade IPMN. The aim of this study was to identify potential markers for the discrimination of high-grade and invasive (HgInv) IPMN from low- and moderate-grade dysplasia IPMN.

METHODS

Laser capture microdissection was used to isolate distinct foci of low-grade, moderate-grade, high-grade, and invasive IPMN from paraffin-embedded archival tissue from 14 patients who underwent resection for IPMN. Most samples included multiple grades in the same specimen. Affymetrix Human Exon microarrays were used to compare low- and moderate-grade dysplasia IPMN with HgInv IPMN.

RESULTS

Sixty-two genes were identified as showing significant changes in expression (P ≤ 0.05 and a 2-fold cutoff), including up-regulation of 41 in HgInv IPMN. Changes in gene expression are associated with biological processes related to malignant behavior including cell motion, cell proliferation, response to hypoxia, and epithelial-to-mesenchymal transition. In addition, altered signaling in several transforming growth factor β-related pathways was exhibited in the progression of IPMN to malignancy.

CONCLUSIONS

This study identifies a set of genes associated with the progression of IPMN to malignancy. These genes are potential markers that could be used to identify IPMN requiring surgical resection.

Pancreatic Cystic Tumors of Mucinous Type

This article presents the clinicopathologic characteristics and differential features of pancreatic mucinous tumors. These tumors, which correspond to the most frequent cystic neoplasms, are encountered with increasing frequency. They comprise the mucinous cystic neoplasms and the intraductal papillary mucinous neoplasms. These tumors are known to progress from dysplasia to invasive carcinoma. Thus, it appears important to distinguish them from other cystic neoplasms and non-neoplastic cysts.

Cystic lesions and intraductal neoplasms of the pancreas

Pancreatic cystic lesions are being detected more frequently given increased use of cross-sectional imaging modalities. The most common cysts encountered are mucinous cysts, which have malignant potential. As many of these lesions are incidental findings, it is important to further evaluate them with endoscopic ultrasound-guided fine needle aspiration for diagnostic purposes and risk stratification. These cysts either require surgical resection or surveillance given the malignant risk. Mucinous cystic neoplasms should be resected. Intraductal papillary mucinous neoplasia (IPMN) has consensus-guideline indications for resection. These include main duct diameter > or = 10 mm, a branch duct size > or = 3 cm, presence of a mural nodule, or cytology suspicious for malignancy. Additionally, all symptomatic cysts, regardless of etiology, should undergo resection. Branch duct IPMN is less aggressive that the main duct variety, and may be conservatively followed. However, the development of an established indication for resection should prompt surgery. Despite generalized guidelines, decisions regarding management of pancreatic cysts should be individualized, accounting for the malignant risk of the lesion and the surgical risk of the patient.

Current management of cystic neoplasms of the pancreas

Over the last decade there has been a dramatic increase in the number of patients identified with pancreatic cysts. This increase has been largely attributed to advances in imaging. The majority of these cysts represent benign neoplasms; however, a significant fraction of these are pre-malignant or malignant. Because the majority of these neoplasms are benign, many reports have advocated a selective approach to surgical resection. Here we review the literature that has contributed to the development of our approach to the management of these cystic neoplasms. We provide an overview of the key features in diagnosis and in predicting malignancy. Particular attention is given to the natural history and management of intraductal papillary mucinous neoplasms (IPMN).

Prevalence of extrapancreatic cancers in patients with histologically proven intraductal papillary mucinous neoplasms of the pancreas: a case-control study

BACKGROUND

Some studies have suggested that intraductal papillary mucinous neoplasms (IPMN) of the pancreas could be associated with extrapancreatic cancers (EPC)--especially from gastric and colorectal origin. The aim of this case-control study was to examine the association of EPC in patients with histologically proven IPMN.

PATIENTS

A case-control study comparing 178 patients with resected IPMN (hyperplasia/low-grade dysplasia.

METHODS

N = 91, high-grade dysplasia/invasive cancer N = 87) with 356 age- and gender-matched controls. EPC were searched for in patients with IPMN and controls, as well as familial histories of cancer and alcohol and tobacco intake. The prevalence and odds ratio were calculated.

RESULTS

No difference was observed between alcohol and tobacco intake in IPMN patients and controls. EPC was found in 30 of 178 (16.8%) patients with IPMN (70% of which preceding IPMN) and in 30 of 356 (8.4%) controls (P = 0.003). The most frequent cancers in patients with IPMN and controls were: breast (30% in each group), prostate (10% and 13%, respectively, not significant [NS]), and colon/rectum (10 and 6%, respectively, NS). No correlation was found between the occurrence of EPC and the grade of IPMN.

CONCLUSIONS

The prevalence of EPC in patients with IPMN is higher as compared with controls. The type and age at onset of EPC do not differ from the general population. Most of the EPCs precede the diagnosis of IPMN. A systematic screening of EPC should be performed only after the age of 50 yr or in case of a familial history of cancer, as yet recommended.

Differentiation of intraductal papillary mucinous neoplasms from other pancreatic cystic masses: comparison of multirow-detector CT and MR imaging using ROC analysis

PURPOSE

To compare the diagnostic performance of multirow-detector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the differentiation of intraductal papillary mucinous neoplasms (IPMNs) from other pancreatic cystic masses.

MATERIALS AND METHODS

A total of 53 patients with pathologically proven pancreatic cystic lesions who had undergone MDCT and MRI were included in this study. Two radiologists analyzed the morphologic features of the lesions and graded the lesion conspicuity on each examination. The readers assigned their confidence level regarding the differentiation of IPMN from other lesions and predicting ductal communication of the lesion. The radiologists' diagnostic confidence was compared using receiver operating characteristic (ROC) analysis.

RESULTS

The Az values for each observer for predicting ductal communication of the lesion and differentiating IPMN from other lesions were as follows: For MRI they were respectively 0.949 and 0.995 for reader 1, and 0.916 and 0.932 for reader 2. For MDCT they were respectively 0.790 and 0.875 for reader 1, and 0.774 and 0.850 for reader 2. In addition, for differentiating IPMNs from other lesions, MRI was significantly more accurate than MDCT (P < 0.05) for one observer, but for the other observer there was no significant difference between the two examinations (P = 0.059). For predicting ductal communication of the cystic lesions for both observers, MRI was significantly more accurate than MDCT (P < 0.05). The weighted kappa values indicate good agreement (kappa = 0.61) between observers for MDCT, and excellent agreement (kappa = 0.82) for MRI.

CONCLUSION

Pancreatic MRI shows better diagnostic performance than MDCT for differentiating IPMNs from other cystic lesions of the pancreas.

Endoscopic ultrasound-guided fine-needle aspiration cytology diagnosis of intraductal papillary mucinous neoplasm of the pancreas is highly predictive of pancreatic neoplasia

Intraductal papillary mucinous neoplasms (IPMN) have been considered difficult to diagnose by fine-needle aspiration (FNA) cytology. We identified 57 cases diagnosed as IPMN or consistent with IPMN by endoscopic ultrasound (EUS)-guided FNA over a 9-yr period. Histologic follow-up was available for 20 patients (35%). Pancreatic neoplasia was demonstrated in 18 of these cases (90%). The histologic diagnoses were IPMN (16 cases), pancreatic intraductal neoplasia (grade 1b, 1 case), invasive mucin-producing adenocarcinoma (1 case), and chronic pancreatitis with a pseudocyst (2 cases). Sixty-two cases of IPMN without coexisting adenocarcinoma were diagnosed by histology during this time period. Of these, 35 (56%) had a preceding EUS-guided FNA. The diagnosis made by EUS-guided FNA in these 35 cases was negative or nondiagnostic (6 cases), benign cyst (1 case), chronic pancreatitis (2 cases), atypical ductal cells (2 cases), adenocarcinoma or suspicious for adenocarcinoma (3 cases), consistent with mucinous cystic neoplasm (4 cases), and IPMN or consistent with IPMN (16 cases). An EUS FNA diagnosis of probable or definite neoplasia was, therefore, made in 71% of cases of histologically proven IPMN.

Intraductal papillary mucinous neoplasms of the pancreas: A surgical perspective

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas represent a relatively "new", but increasingly recognized entity. The emergence of this entity is due primarily to the widespread use of modern imaging methods, but also to a heightened awareness of physicians regarding this cystic neoplasm of the pancreas. No signs or symptoms are pathognomonic of IPMNs, but frequently, patients have a pancreatitis-like abdominal pain. Fully one-third of patients with IPMN are asymptomatic at the time of diagnosis. Cross-sectional imaging (ultrasonography, computed tomography, magnetic resonance cholangiopancreatography), endoscopic retrograde cholangiopancreatography, and endoscopic ultrasonography are the diagnostic and staging methods of choice in the evaluation of patients with IPMNs. IPMNs show a wide spectrum of histologic changes, ranging from adenoma to invasive neoplasm, even within the same neoplasm, suggesting a "field defect" predisposing major segments or even the entire ductal epithelium to the development of IPMN. Fine-needle aspiration/cytology and/or analysis of the cystic fluid may be useful diagnostic tools; however, these examinations are associated with high false-negative rates. Complete surgical resection is the therapeutic method of choice. The extent and type of pancreatectomy remain somewhat controversial but should be based on morphologic changes of the pancreas. Even the role of adjuvant therapy remains unclear; however, being "duct-derived" neoplasms of potential malignant character, some form of adjuvant chemo- or ratio-therapy seems indicated in the presence of invasive disease, despite a "curative" resection. In the absence of invasive disease, prognosis after R0 resection is highly favorable with recurrences of 5-10%. However, invasive IPMNs behave quite similar to ductal adenocarcinoma of the pancreas when analyzed stage-by-stage, with a slightly better prognosis; however, even after an R0 resection, recurrence is common.

Aspect radiologique des tumeurs intracanalaires pancréatiques mucineuses et papillaires

IPMTP is a pancreatic duct disease that can better be diagnosed due to advances in imaging techniques. This probably explains the recent increased frequency of this disease. Enlargement of the main pancreatic duct and/or branch ducts is a typical feature. CT and MRI with MRCP are useful for diagnosis. Features of malignant degeneration are better known. Preoperative staging is performed at CT. Differential diagnosis includes main pancreatic duct dilatation and pancreatic cysts. Recent papers indicate that isolated side branch IPMTP is less frequently malignant. Surgery is indicated in the presence of acute pancreatitis or suspicion of malignant degeneration. Imaging is useful for the follow up of patients with isolated side branch IPMTP. In this paper, the diagnostic, staging and malignant features of IPMTP will be reviewed.

Intraductal tubular neoplasms of the pancreas: histogenesis and differentiation

OBJECTIVES

Intraductal neoplasms of the pancreas are generally referred to as intraductal papillary mucin-producing neoplasms (IPMNs), according to the WHO classification system. Herein, we report that morphologic and immunohistochemical features of intraductal tubular carcinoma (ITC) are quite different from those of intraductal papillary mucinous carcinoma (IPMC).

METHODS

We analyzed histogenesis and differentiation of ITC by light microscopy and immunohistochemistry.

RESULTS

Histologically, ITC was characterized as an intraductal nodular appearances with a monotonous tubular growth pattern without papillary projection. ITC showed de novo-like appearance without sequential progression usually observed in IPMC, suggesting that ITC is a homogeneous neoplasm. Cuboidal tumor cells in ITC resembled normal pancreatic duct epithelia, and the characteristic growth pattern of ITC replaced that of normal pancreatic duct epithelium. Immunohistochemically, ITC cells were positive for MUC-1 on the apical side of the cell membrane. In contrast to ITC cells, IPMC cells were negative for MUC-1, and ductal adenocarcinoma cells were strongly positive for MUC-1, as was the stroma around the cancer. The immunohistochemical staining pattern of DUPAN-2 resembled that of MUC-1. Interestingly, localization of MUC-1 and DUPAN-2 staining in ITC cells was similar to that in normal pancreatic ductules. ITC cells were negative for MUC-2 and MUC-5AC. In contrast, most IPMC cells were positive for MUC-2 and MUC-5AC.

CONCLUSION

Based on our histologic and immunohistochemical findings, the intraductal pancreatic neoplasm (IPN) can be classified into 2 groups: IPN with gastrointestinal differentiation and IPN with pancreatic duct differentiation. Our present data indicated that ITC cells may arise directly from duct epithelia without progression and possessed pancreatic duct differentiation. On the basis of our data, we suggest that classification of pancreatic neoplasms in the WHO and The Armed Forces Institute of Pathology (AFIP) systems should be reconsidered.

Histologic and immunohistochemical comparison of intraductal tubular carcinoma, intraductal papillary-mucinous carcinoma, and ductal adenocarcinoma of the pancreas

OBJECTIVE

To analyze the differences between intraductal tubular carcinoma (ITC) and intraductal papillary-mucinous carcinoma (IPMC), we performed light microscopic and immunohistochemical analysis of 4 cases of ITC, 6 cases of IPMC, and 9 cases of ductal adenocarcinoma of the pancreas.

METHODS AND RESULTS

Light microscopic examination showed no hyperplasia or adenoma around the carcinoma in ITC, and immunohistochemical analysis showed that the apical side of the cell membrane was positive for MUC-1 in almost all ITC cells. In contrast to ITC cells, all IPMC cells were negative for MUC-1 and ductal adenocarcinoma cells were strongly positive for MUC-1 in the cytoplasm and cell membrane. Immunohistochemical staining patterns of DUPAN-2 in ITC resembled those of MUC-1 in these cancers. ITC and IPMC cells were negative for carcinoembryonic antigen, but ductal adenocarcinoma cells were positive. There were no apparent differences in proliferative activity between ITC and IPMC, but ductal adenocarcinoma showed significantly greater activity than either ITC or IPMC.

CONCLUSION

The PCNA-L.I of IPMC and ITC was lower and the cell atypia of them was more mild compared with those of ductal carcinoma, indicating that IPMC possess low-grade malignant potentials. However, we observed differences of growth patterns and mucous secretion between ITC and IPMC of the pancreas.

Evaluation and management of cystic pancreatic tumors: emphasis on the role of EUS FNA

Cystic lesions of the pancreas are increasingly recognized and usually represent pseudocysts or cystic pancreatic tumors (CPTs), but also include congenital cysts, acquired cysts, extrapancreatic cysts, or cystic degeneration of solid tumors. It is important to distinguish CPT lesions given their varied prognosis and therapy. Mucinous varieties of CPTs (mucinous cystic neoplasms and intraductal papillary mucinous tumors) are premalignant or malignant, and surgical resection is generally recommended in good operative candidates. In contrast, nonmucinous CPTs include serous cystadenomas with a very low malignant potential, or pseudocysts, which are always benign. As a result, nonmucinous CPTs are generally resected only when inducing symptoms or complications. Review of the clinical, imaging, laboratory, and pathology information may clarify the specific tumor type. The relatively limited accuracy of any one modality requires that we consider the combined results when making management decisions.

Main-duct intraductal papillary mucinous neoplasms of the pancreas: clinical predictors of malignancy and long-term survival following resection

OBJECTIVE

To describe clinical characteristics and outcomes of a large cohort of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas affecting the main pancreatic duct.

SUMMARY BACKGROUND DATA

IPMNs are being diagnosed with increasing frequency. Preoperative determination of malignancy remains problematic, and reported results of long-term survival following resection are conflicting.

METHODS

The combined databases from the Massachusetts General Hospital and the Pancreatic Unit of the University of Verona were analyzed. To avoid confusing overlap with mucinous cystic neoplasms, only patients with tumors of the main pancreatic duct (with or without side branch involvement) were included. A total of 140 tumors consecutively resected between 1990 and 2002 were classified as either benign (adenoma and borderline tumors) or malignant (carcinoma in situ or invasive cancer) to compare their characteristics and survival.

RESULTS

Men and women were equally affected (mean age 65 years). Seven patients (12%) had adenomas, 40 (28%) borderline tumors, 25 (18%) carcinoma in situ, and 58 (42%) invasive carcinoma. The median age of patients with benign IPMN was 6.4 years younger than those with malignant tumors (P = 0.04). The principal symptoms were abdominal pain (65%), weight loss (44%), acute pancreatitis (23%), jaundice (17%), and onset or worsening of diabetes (12%); 27% of patients were asymptomatic. Jaundice and diabetes were significantly associated with malignant tumors. Five- and 10-year cancer-specific survival for patients with noninvasive tumors was 100%, and comparable survival of the 58 patients with invasive carcinoma was 60% and 50%.

CONCLUSIONS

Cancer is found in 60% of patients with main-duct IPMNs. Patients with malignant tumors are 6 years older than their benign counterparts and have a higher likelihood of presenting with jaundice or new onset diabetes. No patients with benign tumors or carcinoma in situ died of their disease following resection, and those with invasive cancer had a markedly better survival (60% at 5 years) than pancreatic ductal adenocarcinoma. These findings support both the concept of progression of benign IPMNs to invasive cancer and an aggressive policy of resection at diagnosis.

Idiopathic acute pancreatitis

After routine investigations, including a thorough history, routine laboratory study, and noninvasive imaging with transcutaneous ultrasonogram, 10% to 25% of cases of acute pancreatitis have no readily identifiable cause and are termed idiopathic. But modern medicine has made notable advances in uncovering various causes of acute pancreatitis, and several new diagnostic tools that allow clinicians to less invasively approach the patient without sacrificing the diagnostic yield have been introduced. By being knowledgeable of these new changes and by their proper use in a proper circumstances, clinicians will be able to find the cause more accurately and earlier. This better management will not only improve the well-being of the patients but also reduce the number of "true" idiopathic acute pancreatitis to a minimum.

Intraductal papillary mucinous neoplasm: did it exist prior to 1980?

INTRODUCTION

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas was first reported in 1982. It is not clear whether the appearance of this neoplasm is a new epidemic or an old disease previously overlooked.

AIM

To determine whether IPMN existed as a separate entity before 1982.

METHODOLOGY

We reviewed our pathology reports from all cases of pancreatic cancer diagnosed between 1960 and 1980. Pathologic specimens with descriptors--"mucinous," "cystic," or "papillary"--underwent histologic reexamination. Medical records for patients given a new diagnosis of IPMN from this pathologic review were assessed.

RESULTS

Eighty-four of more than 4,000 pathology reports reviewed contained a key word triggering histologic review. IPMN was identified in 21 patients. Patients had a mean age of 63 years (range, 44-77 years) with symptoms present for a mean of 76 months (median, 15 months; range, 1-516 months). Reported symptoms were abdominal pain in 17, jaundice in 13, weight loss in 12, and pancreatic insufficiency in 7 patients. On pathologic review, the in situ component was graded as adenoma in 4, borderline in 4, and carcinoma in 13. Parenchymal invasion was present in 11/21 (52%). Excluding four postoperative mortalities, mean time to death was 58 months (median, 15 months; range, 2-264 months). Seven patients died of IPMN, 4 of other causes without evidence of recurrence, and 6 of unknown causes.

CONCLUSIONS

IPMN existed in its current known form prior to 1982. Our study cannot determine whether the prevalence or incidence has changed since that time.