Malignant islet cell tumor projecting into the main pancreatic duct

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.

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.

Incidental Neuroendocrine Tumor Discovered After Total Pancreatectomy Intended for Islet Autotransplantation: Important Considerations for Surgical Decision-Making

Total pancreatectomy (TP) is a treatment option for patients experiencing chronic pancreatitis (CP) refractory to medical management. Patients who are candidates for TP benefit from islet autotransplantation (IAT), which preserves available β-cell mass and thereby reduces the risk of brittle diabetes. Malignancy is an absolute contraindication for IAT to prevent the transplantation of occult malignant cells. We present the case of a patient with CP who was approved to undergo TP with IAT (TPIAT) but was intraoperatively discovered to have a pancreatic neuroendocrine tumor. The case illustrates a number of important surgical decision-making considerations for patients undergoing TPIAT and should help guide surgeons should they be presented with this clinical scenario. We stress the importance of vigilance for possible malignancy and to consider an intraoperative biopsy to further investigate unexpected findings that might represent an occult pancreatic malignancy in patients with CP undergoing TPIAT.

Pancreatic neuroendocrine neoplasms: diagnosis and management

Pancreatic neuroendocrine neoplasms are uncommon but rising in incidence. There have been recent changes in the WHO nomenclature and a newly proposed American Joint Committee on Cancer TNM staging, which complement each other. These neoplasms are of great medical and radiological interest because of their diverse presenting features and imaging appearances. There is an increased role for both anatomic and functional imaging in the assessment of these neoplasms. A review of the nomenclature, staging, and imaging is presented in this paper.

Acute pancreatitis secondary to neuroendocrine pancreatic tumors: report of 3 cases and literature review

Pancreatic tumors (particularly neuroendocrine) are an uncommon cause of acute pancreatitis (AP). This is a report of 3 cases of acute pancreatitis secondary to advanced neuroendocrine tumors and a literature review. Including these cases, only 30 have been reported. Most cases are non-functioning, diagnosed in an advanced stage, associating mild pancreatitis and in patients older than forty. Pancreatic neuroendocrine tumors are an uncommon cause of AP but must be included in the differential diagnosis of this disease, especially if the patient is older than 40 and the etiology of the AP is not clear.

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.

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.

Carcinoid tumors of the pancreas: dynamic CT and MRI features with pathological correlation

BACKGROUND

Carcinoid tumor of the pancreas is rare, and there are few reports that described its CT or magnetic resonance imaging (MRI) findings. We describe the characteristic CT and MRI findings in four cases of carcinoid tumor of the pancreas.

METHODS

Radiologic and pathologic features were analyzed in four patients. All patients underwent triple-phase dynamic CT and MRI.

RESULTS

The tumor size in the four cases ranged 15-20 mm and intratumoral calcification was detected in one case. On triple-phase dynamic CT, the peak enhancement of the tumors was seen at the arterial dominant phase in three cases; the remaining one was at the portal venous phase with prolonged contrast-enhancement effect. The tumors showed low to high signal intensity on T2-weighted images. Dilatation of the main pancreatic ducts (MPDs) distal to the tumors was seen in three cases, in which tumor invasion into the MPDs was pathologically confirmed. Furthermore, the tumors having mild to severe fibrosis pathologically invaded into the peripancreatic lymphatics or nerves.

CONCLUSION

It would be characteristic of carcinoid tumor of the pancreas to be well enhanced at the arterial dominant phase on dynamic CT, and to highly invade into the MPDs and the peripancreatic lymphatics or nerves.

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 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.

Pancreatic carcinoid tumor with obstructive pancreatitis: multislice helical CT appearance: case report

Carcinoid tumor of the pancreas is rare. Moreover, obstructive pancreatitis secondary to a pancreatic carcinoid tumor is extremely rare. We report a case of pancreatic carcinoid tumor in a 50-year-old male who presented with pancreatitis. On multislice helical computed tomography, the main pancreatic duct was obstructed by a small round tumor, and the main pancreatic duct proximal to the tumor was dilated. The correlation between the main pancreatic duct and the tumor was well depicted on minimum intensity projection image. This is the first report of multislice helical computed tomorgraphic and minimum intensity projection image findings of a pancreatic carcinoid tumor presenting with pancreatitis.