Intraductal growth of a nonfunctioning endocrine tumor of the pancreas

Rare Solid Pancreatic Lesions on Cross-Sectional Imaging

Several solid lesions can be found within the pancreas mainly arising from the exocrine and endocrine pancreatic tissue. Among all pancreatic malignancies, the most common subtype is pancreatic ductal adenocarcinoma (PDAC), to a point that pancreatic cancer and PDAC are used interchangeably. But, in addition to PDAC, and to the other most common and well-known solid lesions, either related to benign conditions, such as pancreatitis, or not so benign, such as pancreatic neuroendocrine neoplasms (pNENs), there are solid pancreatic lesions considered rare due to their low incidence. These lesions may originate from a cell line with a differentiation other than exocrine/endocrine, such as from the nerve sheath as for pancreatic schwannoma or from mesenchymal cells as for solitary fibrous tumour. These rare solid pancreatic lesions may show a behaviour that ranges in a benign to highly aggressive malignant spectrum. This review includes cases of an intrapancreatic accessory spleen, pancreatic tuberculosis, solid serous cystadenoma, solid pseudopapillary tumour, pancreatic schwannoma, purely intraductal neuroendocrine tumour, pancreatic fibrous solitary tumour, acinar cell carcinoma, undifferentiated carcinoma with osteoclastic-like giant cells, adenosquamous carcinoma, colloid carcinoma of the pancreas, primary leiomyosarcoma of the pancreas, primary and secondary pancreatic lymphoma and metastases within the pancreas. Therefore, it is important to determine the correct diagnosis to ensure optimal patient management. Because of their rarity, their existence is less well known and, when depicted, in most cases incidentally, the correct diagnosis remains challenging. However, there are some typical imaging features present on cross-sectional imaging modalities that, taken into account with the clinical and biological context, contribute substantially to achieve the correct diagnosis.

Indications to total pancreatectomy for positive neck margin after partial pancreatectomy: a review of a slippery ground

The extension of a partial pancreatectomy up to total pancreatectomy because of positive neck margin examined at intraoperative frozen section (IFS) analysis is an accepted procedure in modern pancreatic surgery with good accuracy. The goal of this practice is to improve the rate of radical (R0) resection in malignant tumors, mainly pancreatic ductal adenocarcinoma (PDAC), and to completely resect pre-invasive neoplasms such as intraductal papillary mucinous neoplasms (IPMNs). In the setting of IPMNs there is a consensus for pancreatic re-resection when high-grade dysplasia and invasive cancer are present at the neck margin. The presence of denudation is another indication for further resection in IPMNs. The role of IFS analysis in the management of pancreatic cancer is more debated. The presence of a positive intraoperative transection margin can be considered the surrogate of a biologically aggressive disease associated with a poorer prognosis. There are conflicting data regarding possible advantages of pancreatic re-resection up to total pancreatectomy, and the lack of randomized trials comparing different strategies does not offer a definitive answer. The goal of this review is to provide an up-to-date overview of the role IFS analysis of pancreatic margin and of pancreatic re-resection up to total pancreatectomy considering different pancreatic tumors.

Pancreatic Neuroendocrine Neoplasm Invading the Entire Main Pancreatic Duct Diagnosed by a Preoperative Endoscopic Biopsy

A 78-year-old man was referred to our hospital for a detailed examination of a pancreatic tumor that filled the main pancreatic duct (MPD). The histological diagnosis of the endoscopic biopsy specimen was neuroendocrine tumor (NET) G3. The patient subsequently underwent total pancreatectomy. The histological diagnosis of the surgical specimen was also NET G3. This is the first report of a NET that occupied the MPD and was diagnosed by a preoperative endoscopic biopsy through the papilla of Vater. This case is a good example of a histopathological diagnostic method for pancreatic tumors invading the entire MPD.

Intraductal Tubulopapillary Neoplasm of the Pancreas: A Clinicopathologic and Immunohistochemical Analysis of 33 Cases

Intraductal tubulopapillary neoplasm (ITPN) is a relatively recently described member of the pancreatic intraductal neoplasm family. Thus, the literature on its histologic and immunohistochemical features, clinical behavior, and its similarities and differences from other pancreatic neoplasms is limited. Thirty-three cases of ITPN, the largest series to date, were identified. Immunohistochemical labeling for cytokeratins, glycoproteins, pancreatic enzymes, markers for intestinal and neuroendocrine differentiation, and antibodies associated with genetic alterations previously described in pancreatic neoplasms was performed. Clinicopathologic features and survival was assessed. Seventeen patients were female and 14 were male. Mean age was 55 years (range, 25 to 79 y). Median overall tumor size was 4.5 cm (range, 0.5 to 15 cm). Forty-five percent of the tumors occurred in the head, 32% in the body/tail, and 23% showed diffuse involvement. Microscopically, the tumors were characterized by intraductal nodules composed of tightly packed small tubular glands lined by cuboidal cells lacking apparent mucin. Although it was often challenging to determine its extent, invasion was present in 71%. Almost all tumors labeled for CAM5.2, CK7, and CK19; most expressed CA19.9, MUC1, and MUC6. CDX2, MUC2, trypsin, chymotrypsin, chromogranin, and synaptophysin were not expressed. SMAD4 expression was retained in 100%; p16 expression and p53 overexpression was seen in 33% and 27%, respectively. Follow-up information was available for 22 patients (median follow-up, 45 mo; range, 11 to 173 mo). Two patients with invasive carcinoma died of disease at 23 and 41 months, respectively. One patient died of unrelated causes at 49 months. Twelve patients were alive with disease. Seven patients were alive with no evidence of disease. The overall 1-, 3-, and 5-year survival rates were 100% in patients without an invasive component and 100%, 91%, and 71%, respectively, in patients with an invasive component (P=0.7). ITPN is a distinct clinicopathologic entity in the pancreas. Despite the difficulties of determining the extent of invasive carcinoma in many cases, the overall outcome seems to be relatively favorable and substantially better than that of conventional pancreatic ductal adenocarcinoma, even when only the cases with invasive carcinoma are considered.

A mixed adenoneuroendocrine carcinoma of the pancreas: a case report

A tumor consisting of an adenocarcinoma component and a neuroendocrine carcinoma component, with each component accounting for at least 30% of the tumor, is defined as a mixed adenoneuroendocrine carcinoma (MANEC). We report a case of MANEC of the pancreas. A 63-year-old man presented with hyperglycemia and was referred to our hospital for further examination. Abdominal contrast-enhanced computed tomography (CT) revealed a mass of 2 cm in size in the pancreas head with portal vein narrowing. Fluorin-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) CT revealed increased accumulation in the mass of the pancreas head. Endoscopic retrograde cholangiopancreatography (ERCP) showed severe narrowing of the main pancreatic duct. Cytological analysis by endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) suggested a neuroendocrine tumor. Under the diagnosis of neuroendocrine tumor, pancreaticoduodenectomy with portal vein resection and regional lymph node dissection was performed with curative intent. Histological examination revealed that the tumor consisted of two cell populations. One was well- to moderately differentiated tubular adenocarcinoma. This cell component accounted for 45% of the whole tumor. The second component was non-adenocarcinoma cells arranged in a nest, and the cells had round nuclei, abundant cytoplasm, and coarse chromatin. The Ki67 labeling index was 40%. Immunohistochemically, the adenocarcinoma cells were positive for CEA but negative for chromogranin A (CgA) and synaptophysin (Syn), while the non-adenocarcinoma cells were positive for the expression of CgA and Syn but negative for CEA. Based on the findings, a diagnosis of MANEC of the pancreas was made. Postoperatively, lymph node metastasis and peritoneal dissemination developed rapidly and he died the 6 months after the operation. Due to the small number of reported cases of MANEC of the pancreas, its clinical behavior remains unclear and a standardized management protocol has not been established. Further investigation of more cases of this rare entity is necessary.

Pancreatic nonfunctioning neuroendocrine tumor with the main pancreatic duct obstruction presenting as excessive hyperglycemia: a case report and review of the literature

We present the case of a 65-year-old man with a pancreatic nonfunctioning neuroendocrine tumor causing main pancreatic duct obstruction that presented as excessive hyperglycemia. We considered the tumor elicited worsening of diabetes in this case, and we performed review of the relevant literature.

Curative resection of a huge malignant pancreatic endocrine tumor by pancreatoduodenectomy with portal and superior mesenteric vein resection and reconstruction using the right ovarian vein: report of a case

Nonfunctioning pancreatic endocrine tumors (PETs) are rare and generally asymptomatic. A 68-year-old woman who had refused treatment for a pancreatic mass, revealed by ultrasonography to be 55 mm in diameter, was referred to us again 29 months later with jaundice. Investigations showed an 82-mm tumor in the head of pancreas, exposed from the papilla of Vater to the duodenal lumen. After biliary decompression and drainage, we performed pancreatoduodenectomy with resection of the portal vein and superior mesenteric vein, followed by reconstruction using a cylindrically customized autologous graft harvested from the right ovarian vein. The tumor was resected curatively. Microscopically, it consisted of trabecular and ribbon-like arrangement of neoplastic cells. Immunohistochemical staining was positive for chromogranin A and synaptophysin and negative for insulin, gastrin, glucagons, somatostatin, and pancreatic peptide. Although metastasis was detected in a lymph node along the superior mesenteric vein with perineural invasion, the portal and superior mesenteric veins had not been invaded. The diagnosis was well-differentiated nonfunctioning PET. The patient had an uneventful postoperative course, and there has been no evidence of recurrence in 12 months.

Nonfunctioning pancreatic endocrine tumor with extension into the main pancreatic duct: report of a case

Pancreatic endocrine tumors (PETs) rarely involve the main pancreatic duct. We report a case of malignant nonfunctioning pancreatic endocrine tumor (NFPET) with prevalent intraductal growth. A 47-year-old woman was referred to us after ultrasonography at a routine health check showed diffuse swelling of the pancreas. Preoperative imaging showed a solid mass in the tail of the pancreas and a bulging intraductal mass in the main pancreatic duct. We performed total pancreatectomy because the tumor occupied almost the entire lumen of the main pancreatic duct. Histological examination confirmed well-differentiated endocrine carcinoma. We review reported cases of the intraductal growth of NFPETs and discuss the pathogenesis of these unusual tumors.

Primary neuroendocrine tumors of the main pancreatic duct: a rare entity

Very few cases of primary neuroendocrine tumors of the main pancreatic duct have been reported. This paucity has hampered an accurate description of the distinctive clinical and pathological features of these tumors and the correct evaluation of the diagnostic and therapeutic problems which they may raise. We report here five additional cases in order to underline the clinical, histological, and immunohistochemical features of this tumor entity. There were three male and two female, aged 43-72 years; in all patients, but one, who presented with epigastric pain, the diagnosis was made after the incidental discovery of a dilatation of the main pancreatic duct. The preoperative diagnosis was ductal adenocarcinoma in one case, IPMN in one case and neoplastic stenosis of unknown etiology in four cases. Surgical resection was performed in all cases. The diagnosis of neuroendocrine tumor was made at histological examination. All lesions were small, ranging from 5 to 15 mm. They had a predominantly intramural growth. The growth pattern was nodular in three cases, circumferential in two; there was no intra-luminal component. All cases were well-differentiated neuroendocrine neoplasms of low histological grade (G1); four cases expressed serotonin. One case was associated with regional lymph node metastases. All cases were cured by surgery alone; no recurrence was observed at the end of the follow-up period. In conclusion, despite their rarity, primary neuroendocrine tumors of the main pancreatic duct deserve recognition and must be considered in the etiological diagnosis of ductal stenosis.

Endocrine neoplasms of the pancreas: pathologic and genetic features

CONTEXT

Pancreatic endocrine neoplasms (PENs) are diagnostically challenging tumors whose natural history is largely unknown. Histopathology allows the distinction of 2 categories: poorly differentiated high-grade carcinomas and well-differentiated neoplasms. The latter include more than 90% of PENs whose clinical behavior varies from indolent to malignant and cannot be predicted by their morphology.

OBJECTIVES

To review the literature and report on additional primary material about the clinicopathologic features, classification, staging, grading, and genetic features of PENs.

DATA SOURCES

Literature review of relevant articles indexed in PubMed (US National Library of Medicine) and primary material from the authors' institution.

CONCLUSIONS

The diagnosis of PEN is generally easy, but unusual features may induce misdiagnosis. Immunohistochemistry solves the issue, provided that the possibility of a PEN has been considered. Morphology allows the distinction of poorly differentiated aggressive carcinomas from well-differentiated neoplasms. The World Health Organization classification criteria allow for the discernment of the latter into neoplasms and carcinomas with either benign or uncertain behavior. The recently proposed staging and grading systems hold great promise for permitting a stratification of carcinomas into clinically significant risk categories. To date, inactivation of the MEN1 gene remains the only ascertained genetic event involved in PEN genesis. It is inactivated in roughly one-third of PENs. The degree of genomic instability correlates with the aggressiveness of the neoplasm. Gene silencing by promoter methylation has been advocated, but a formal demonstration of the involvement of specific genes is still lacking. Expression profiling studies are furnishing valuable lists of mRNAs and noncoding RNAs that may advance further the research to discover novel markers and/or therapeutic targets.

Intraductal pancreatic neuroendocrine tumor

Intraductal lesions of the pancreas are usually due to intraductal papillary mucinous neoplasms and the less common intraductal tubular adenoma. Cases of acinar cell carcinoma within intraductal location have also been encountered recently. Pancreatic neuroendocrine tumors are rarely encountered within the main pancreatic duct. A 74-year-old male presented with non-specific abdominal symptoms and was found to have an obstructive lesion in the main pancreatic duct with associated chronic pancreatitis. A distal pancreatectomy was performed which revealed a solid and cystic tumor measuring 6 x 3 x 2 cm situated wholly within the main pancreatic duct. It formed an obstructing intraluminal polypoid lesion that resulted in surrounding chronic pancreatitis. Microscopic evaluation of the mass showed it to be a well-differentiated pancreatic neuroendocrine tumor with entrapped, non-malignant tubules. Intraductal pancreatic neuroendocrine tumors may occur in two settings. Firstly, and more commonly, there is a parenchymal-based tumor that then encroaches on and pushes into the main pancreatic duct. The less common scenario is of a primary intraductal location without a pancreatic parenchymal lesion. While an intraductal location of a pancreatic neuroendocrine tumor is rare, it should be borne in mind when confronted by an intraductal lesion in the pancreas.

Nonfunctioning Pancreatic Endocrine Neoplasm Presenting as Asymptomatic, Isolated Pancreatic Duct Stricture: A Case Report and Review of the Literature

Morphologic irregularities of the pancreatic duct are often noted on abdominal imaging studies obtained for unrelated symptoms or conditions. We report the case of a patient who was found to have an incidental, isolated pancreatic duct dilatation on multiple imaging studies and who was found to have a nonfunctioning pancreatic endocrine neoplasm at resection. His prognosis is excellent based on the histology of the lesion and a curative resection. This case highlights the importance of fully investigating incidental pancreatic duct abnormalities regardless of the setting in which they are found.

A malignant nonfunctioning pancreatic endocrine tumor with a unique pattern of intraductal growth

The intraductal growth of nonfunctioning pancreatic endocrine tumors (NFPTs) is considered to be rare, and in our survey of the English-language literature, we found only three cases to have been described previously. We herein report the case of a 36-year-old man with a malignant NFPT that uniquely grew within the lumen of the main pancreatic duct (MPD) and completely obstructed the MPD, as shown by endoscopic retrograde pancreatography (ERP). Endoscopic ultrasonography clearly detected the tumor with intraductal growth. In addition, positron emission tomography (PET), using 18F-fluorodeoxyglucose (FDG) and computed tomography (CT) with the same scanner (FDG-PET/CT) showed enhanced uptake of FDG in the tumor. A pylorus-preserving pancreaticoduodenectomy and regional lymphadenectomy were performed under the preoperative diagnosis of an NFPT. Microscopically, positive immunoreactions for synaptophisin and vasoactive intestinal peptide indicated neuroendocrine differentiation of the tumor, while in addition, metastasis to a lymph node along the common hepatic artery was also observed. The patient has survived for 6 months after the surgery without any evidence of recurrence or metastasis. Both ERP and FDG-PET/CT were thus found to be useful for predicting the malignant potential of an NFPT in the preoperative diagnosis.

[Pancreatic intraductal tubular carcinoma: a sub-group of intraductal papillary-mucinous tumors or a distinct entity? A case report and review of the literature]

We report the case of a 67-year-old man presenting with an isolated 3 cm mass of the pancreatic tail revealed by weight loss. Distal pancreatectomy and splenectomy were performed. Microscopically, the tumor filled the main pancreatic duct, extending into the smaller ducts and was associated with a minor adenocarcinomatous invasive component. The intraductal tumor showed a cribriform pattern, atypical cells without mucus and a MUC1+, MUC2-, MUC5AC- phenotype, all characteristics of intraductal tubular carcinoma, a new entity described by Japanese authors. The differential diagnosis and its relationship with intraductal papillary-mucinous tumors are discussed.

Pancreatic endocrine tumors with intraductal growth into the main pancreatic duct and tumor thrombus within the portal vein: a case report and review of the literature

Pancreatic endocrine tumors are rare tumors classified into "functioning" and "nonfunctioning" tumors. A 68-year-old man was admitted to our hospital with the chief compliant of abdominal pain. Various imaging studies demonstrated a mass in the head of the pancreas with intraductal growth into the main pancreatic duct and an intraportal mass. The patient underwent a curative surgical operation. Histopathological examination revealed that it was nonfunctioning endocrine carcinoma of the pancreas. This is the first reported case of a pancreatic endocrine tumor with intraductal growth into the main pancreatic duct and tumor thrombus within the portal vein.

An unusual case of undifferentiated carcinoma in situ with osteoclast-like giant cells of the pancreas

OBJECTIVES

We report an unusual case of undifferentiated carcinoma in situ with osteoclast-like giant cells (UC with OGCs) in a 68-year-old Japanese woman.

METHODS

Preoperative examinations revealed an unidentifiable mass lesion within the main pancreatic duct (MPD) in the pancreatic head, accompanied by a dilated MPD distal to the mass lesion, which was suspected to be an intraductal papillary-mucinous neoplasm of the main-duct type with acute pancreatitis because of an increased serum amylase level. A pancreaticoduodenectomy was performed.

RESULTS

A pencil-like tumor occupied the lumen of the MPD of the pancreatic head without a visible pancreatic parenchymal mass. The intraductal tumor included a sheet of spindle cells intermingled with scattered OGCs and pleomorphic giant cells. A poorly developed glandular pattern was occasionally observed at the tumor periphery. These findings were consistent with conventional UC with OGCs. However, extraductal invasion was not found in an extensive histopathologic examination, although focal intraductal spreading into the epithelium of the first branch of the MPD was observed.

CONCLUSIONS

Undifferentiated carcinoma with OGCs usually exhibits an invasive tumor at diagnosis and is associated with a poor outcome, but the patient is alive without recurrence 22 months after surgery. To our knowledge, this is the first reported case of UC in situ without evident extraductal invasion in English literature.

Pancreatic acinar cell carcinoma extending into the common bile and main pancreatic ducts

Acinar cell carcinoma (ACC) of the pancreas is relatively rare, accounting for only approximately 1% of all exocrine pancreatic tumors. A 69-year-old man was found to have a mass lesion measuring approximately 4 cm in diameter in the pancreatic head on ultrasound, abdominal dynamic CT, and percutaneous transhepatic cholangiography. Magnetic resonance cholangiopancreatography showed defect of the lower common bile duct (CBD) due to obstruction by the tumor cast. Histopathologically, the pancreatic head tumor invaded the main pancreatic duct (MPD) and CBD with extension into the CBD in a form of tumor cast. The tumor cells consisted of a solid proliferation with abundant eosinophilic cytoplasm and round nuclei in an acinar and trabecular fashion. A 55-year-old man with upper abdominal pain and nausea, had a cystic lesion approximately 3 cm in size in the pancreatic tail on CT. Histopathologically, the tumor was encapsulated by fibrous capsule and had extensive central necrosis with solid areas in the tumor periphery, and invaded with extension into the MPD in a form of tumor cast. The tumor cells resembled acinar cells in solid growths. Two resected cases of ACC with unusual tumor extension into the CBD and the MPD, respectively, are reported.