Synchronous pancreatic solid pseudopapillary neoplasm and intraductal papillary mucinous neoplasm

Solid pseudopapillary neoplasm (SPN) is a rare and low-grade malignant pancreatic neoplasm composed of poorly cohesive monomorphic neoplastic cells forming solid and pseudopapillary structures with frequent hemorrhagic-cystic degeneration. Intraductal papillary mucinous neoplasm (IPMN) is a pancreatic exocrine tumor composed of intraductal papillary growth of mucin containing neoplastic cells in the main pancreatic duct or its major branches. In the case presented here, a 53-year-old, Japanese man was found to have multiple cystic lesions and dilatation of the main pancreatic duct in the neck of the pancreas. Histological examination revealed a main-duct and branch-duct type IPMN, of the gastric-type, involving the neck of the pancreas, associated with a 0.5 cm SPN in the caudal side of the IPMN. We diagnosed this case as synchronous SPN and IPMN. As far as we know, only one other case of synchronous SPN and IPMN has been reported. Both the present case and the previously reported case showed abnormal nuclear expression of β-catenin in SPN, whereas IPMN showed no abnormal nuclear expression. These results suggest that β-catenin abnormality is not a common pathogenetic factor of synchronous SPN and IPMN.     

Helicobacter pylori is undetectable in intraductal papillary mucinous neoplasm

BackgroundAbout half of the world population is infected with Helicobacter pylori (H. pylori), a bacterium associated with gastric cancer and considered to be a risk factor for pancreatic ductal adenocarcinoma. Whether the bacterium is associated with intraductal papillary mucinous neoplasm, believed to be a precursor of pancreatic ductal adenocarcinoma, is unknown. The aim of this study was to investigate the presence of H. pylori DNA in tissue sections of intraductal papillary mucinous neoplasm.MethodsThe presence of H. pylori DNA was tested in a retrospective controlled study of formalin-fixed, paraffin-embedded pancreatic tissues from 24 patients who underwent surgery for intraductal papillary mucinous neoplasm. Histologically normal tissues surrounding neoplasms were used as control. H. pylori DNA was evaluated after deparaffinization, DNA extraction, and purification, and results were evaluated statistically.ResultsSamples were collected from 13 males and 11 females with mean age 59 years (range 44–77), and consisted of 19 cases of main-duct and three cases of branched-duct intraductal papillary mucinous neoplasm. Two patients were diagnosed with pancreatic cancer and main-duct intraductal papillary mucinous neoplasm. H. pylori DNA was not detected either in intraductal papillary mucinous neoplasm tissue, or in surrounding normal tissue.ConclusionsAlthough H. pylori has been implicated in pancreatic ductal adenocarcinoma, it may not play a key role in the development of intraductal papillary mucinous neoplasm.     

Molecular mechanism of intraductal papillary mucinous neoplasm and intraductal papillary mucinous neoplasm‐derived pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal human malignancies. Dissecting the mechanisms underlying PDA development is important for developing early detection methods and effective prevention and therapies for the disease. PDA is considered to arise from distinct precursor lesions, including pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasia (IPMN). However, little is known about molecular mechanisms of development of IPMN and IPMN‐derived PDA. We have recently reported that loss of Brg1, a core subunit of SWI/SNF chromatin remodeling complexes, cooperates with oncogenic Kras to form cystic neoplastic lesions that resemble human IPMN and progress to PDA. Brg1 null IPMN‐PDA is less lethal compared to PanIN‐derived PDA (PanIN‐PDA) driven by mutant Kras and hemizygous p53 deletion, mirroring prognostic trends in PDA patients. Brg1 null IPMN‐PDA possesses a distinct molecular signature that supports less malignant potential compared to PanIN‐PDA. Furthermore, Brg1 deletion inhibits Kras‐dependent PanIN development from adult acinar cells, but promotes Kras‐driven preneoplastic transformation in adult duct cells. Therefore, Brg1 is a determinant of context‐dependent Kras‐driven pancreatic tumorigenesis and chromatin remodeling may underlie the development of distinct PDA subsets. Understanding molecular mechanism of IPMN and IPMN‐derived PDA could provide critical clues for novel diagnostic and therapeutic strategies of the disease.     

Management of intraductal papillary mucinous neoplasm of the pancreas

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is a distinct entity characterized by papillary proliferations of mucin-producing epithelial cells with excessive mucus production and cystic dilatation of the pancreatic ducts. IPMNs have malignant potential and exhibit a broad histologic spectrum, ranging from adenoma to invasive carcinoma. IPMNs are classified into main duct and branch duct types, based on the site of tumor involvement. IPMN patients have a favorable prognosis if appropriately treated. The postoperative 5-year survival rate is nearly 100% for benign tumors and noninvasive carcinoma, and approximately 60% for invasive carcinoma. A main duct type IPMN should be resected. Surgical treatment is indicated for a branch duct IPMN with suspected malignancy (tumor diameter ≥ 30 mm, mural nodules, dilated main pancreatic duct, or positive cytology) or positive symptoms. Malignant IPMNs necessitate lymph node dissection (D1). IPMNs are associated with a high incidence of extrapancreatic malignancies and pancreatic ductal carcinoma.     

Clinical aspects of intraductal papillary mucinous neoplasm of the pancreas

Intraductal papillary mucinous neoplasm (IPMN) is a spectrum of neoplasia in the pancreatic duct epithelium characterized by cystic dilation of the main and/or branch pancreatic duct. According to the site of involvement IPMNs are classified into three categories, i.e., main duct type, branch duct type, and combined type. Most branch duct IPMNs are benign, whereas the other two types are often malignant. A large size of branch duct IPMN and marked dilation of the main pancreatic duct indicate the presence of adenoma at least. The additional existence of large mural nodules increases the possibility of malignancy in all types. Of recent interest is the relatively high prevalence of synchronous and/or metachronous malignancy in various organs, including the pancreas. The prognosis is favorable after complete resection of benign and noninvasive malignant IPMNs. Malignant IPMNs acquiring aggressiveness after parenchymal invasion necessitate adequate lymph node dissection. On the other hand, asymptomatic branch duct IPMNs without mural nodules can be observed without resection for a considerably long time. This review addresses available data, current understanding, controversy, and future directions.     

Pancreatic intraductal papillary mucinous neoplasm in a patient with Lynch syndrome

Intraductal papillary mucinous neoplasm (IPMN) is a mucin-producing epithelial neoplasm that carries a risk of progression to invasive pancreatic ductal adenocarcinoma. Lynch syndrome is an autosomal dominant condition caused by germline mutations in mismatch repair genes such as MSH2 that lead to microsatellite instability and increased risk of tumor formation. Although families with Lynch syndrome have an increased risk of pancreatic cancer, a clear connection between Lynch syndrome and IPMN has not been drawn. We present a report of a 58 year-old Caucasian woman with multiple cancers and a germline mutation of MSH2 consistent with Lynch syndrome. A screening abdominal computed tomography scan revealed a dilated main pancreatic duct and cystic ductular structure in the uncinate process that were consistent with IPMN of the main pancreatic duct on excision. Immunohistochemistry and polymerase chain reaction of the patient’s pancreas specimen did not reveal microsatellite instability or mismatch repair gene loss of expression or function. Our findings may be explained by the fact that loss of mismatch repair function and microsatellite instability is a late event in neoplastic transformation. Given the relative rarity of main duct IPMN, its appearance in the setting of somatic MSH2 mutation suggests that IPMN may fit into the constellation of Lynch syndrome related malignancies.     

Malignancies associated with intraductal papillary mucinous neoplasm of the pancreas

AIM: As intraductal papillary mucinous neoplasm (IPMN) has a favorable prognosis, associated malignancies have potential significance in these patients. We examined the incidence and characteristics of pre-existing, coexisting and subsequent malignancies in patients with IPMN. METHODS: Seventy-nine cases of IPMN were diagnosed by detection of mucous in the pancreatic duct during endoscopic retrograde pancreatography. Histological diagnosis was confirmed in 30 cases (adenoma (n=19) and adenocarcinoma (n =11). Other primary malignancies associated with IPMN, occurring in the prediagnostic or postdiagnostic period, were investigated. Postdiagnostic follow-up period was 3.3±0.5 years (range, 0.2-20 years). RESULTS: Other 40 malignancies occurred in 28 patients (35%). They were found before(n=15), at (n=19) and after (n=6) the diagnosis of IPMT. Major associated malignancies were gastric cancer (n=12), colonic cancer (n=7), esophageal cancer (n=4), pulmonary cancer (n=4), and independent pancreatic cancer (n=3). Pancreatic cancer was synchronous with IPMN in two patients and metachronous in one (3 years after diagnosis of IPMN). Thirty-one lesions were treated surgically or endoscopically. Fourteen patients died of associated cancers. Development of other malignancies was related to age (71.9±8.2 vs66.8±9.3, P<0.05), but not to gender or site of the tumor. CONCLUSION: IPMN is associated with a high incidence of other malignancies, particularly gastric and colonic cancers. Common genetic mechanisms between IPMN and other associated malignancies might be present. Clinicians should pay attention to the possibility of associated malignancies in preoperative screening and follow-up of patients with IPMN.     

Multifocal intraductal papillary mucinous neoplasm of the pancreas-A case report

Cystic neoplasms of the pancreas are relatively rare, comprising 10 percent of pancreatic cysts and only 1 percent of pancreatic cancers. Cystic neoplasms include mucinous cystic neoplasms, serous cystadenomas, papillary cystic tumors, cystic islet cell tumors and intraductal papillary mucinous neoplasms of the pancreas （IPMNs）. IPMN was first described in 1982. It has been most commonly described in 60 to 70 years old males, and represents a relatively ＂new＂ but increasingly recognized disease. The improvement and widespread use of modern imaging equipments and heightened awareness of physicians contribute to the increasing incidence of IPMN. The majority of IPMNs are located in the pancreatic head （75%） while the rest involves the body/tail regions. Multifocal IPMNs have been hypothesized, but the true presence of multifocality is unknown. Here we present a 72-year- old male diagnosed with IPMN （carcinoma in situ） in the pancreatic head and a branch duct type IPMN （duct atypia） in the pancreatic body and tail. The patient underwent a Whipple intervention and a distal pancreatectomy. A three-year disease-free survival has been observed so far.     

Surgical decompression in the patients of pancreatic intraductal papillary mucinous neoplasm

Intraductal papillary mucinous neoplasm (IPMN) is characterized by cystic dilatation of the main and/or branch pancreatic duct by intraductal growth of mucin-producing columnar epithelia. The malignancy is determined by the degree of epithelial dysplasia. Because most IPMNs are slow growing and the prognosis may be favorable even when the IPMN is malignant, aggressive surgical treatment is suggested after considering operative and postoperative risks. Palliative surgery should be considered in some circumstances, such as other synchronous malignancy or systemic comorbidity. Here, we report two patients with IPMN treated successfully by surgical decompression of pancreatic duct.     

Laparoscopic single-branch resection of the pancreas for intraductal papillary mucinous neoplasm

Although laparoscopic pancreatic resections have become more common, laparoscopic minimally invasive and function-preserving pancreatic resections have not been widely accepted. Branch-type intraductal papillary mucinous neoplasm (IPMN) has a low-grade malignant potential and shows a favorable prognosis. In branch-type IPMN, minimal resection techniques with preservation of the pancreatic functional reserve have advantages over the more conventional pancreaticoduodenectomy. We describe herein laparoscopic single-branch resection of the pancreas for branchtype IPMN. This surgical procedure is a novel and an ideal minimally invasive method for the resection of branch-type IPMN. In addition, our endoscopic nasopancreatic drainage (ENPD) tube-guided technique is useful for precise resection of the tumor and for the prevention of pancreatic fistula.     

Concomitant pancreatic adenocarcinoma in a patient with branch-duct intraductal papillary mucinous neoplasm

Branch duct intraductal papillary mucinous neoplasms (BD-IPMN) are pre-malignant pancreatic cystic lesions which carry a small risk of malignant transformation within the cyst. Guidelines exist with respect to surveillance of the cysts using computed tomography, magnetic resonance imaging, and/or endoscopic ultrasound (EUS). There are reports that patients with IPMNs are at increased risk of developing pancreatic adenocarcinoma, which arises in an area separate to the IPMNs. We present two cases of pancreatic adenocarcinoma arising within the parenchyma, distinct from the IPMN-associated cyst, identified with EUS. This case report highlights that patients with BD-IPMN are at increased risk for pancreatic adenocarcinoma separate from the cyst and also the importance for endosonographers to carefully survey the rest of the pancreatic parenchyma separate from the cyst in order to identify small pancreatic adenocarcinomas.