Minute mixed ductal-endocrine carcinoma of the pancreas with predominant intraductal growth

We report a rare case of minute (5 mm x 4 mm) mixed ductal-endocrine carcinoma of the pancreas with predominant intraductal growth. A 34-year-old Japanese man was admitted because of elevated serum pancreatic enzymes. Endoscopic retrograde pancreatography revealed an unidentified material of 18 mm within the main pancreatic duct. Stone or parasite with acute pancreatitis was suspected clinically, and the biopsy revealed malignant cells positive for CA19-9, carcinoembryonic antigen (CEA) and synaptophysin. No apparent tumor was identified in the pancreas by various imaging techniques. Resection of pancreatic body and tail was performed. Grossly, the main pancreatic duct in the pancreatic body was occluded by as much as 20 mm. The pancreas had minute carcinoma of 5 mm x 4 mm just around the occluded main pancreatic duct. The tumor cells invaded the main pancreatic duct and spread within it as long as 20 mm. Histologically, the carcinoma had biphasic pattern; one was ductal carcinoma with tubular formations and another was carcinoma with neuroendocrine features. These two elements were admixed, and the ductal element comprised 30% while the endocrine element comprised 70%. The ductal element was immunoreactive for cytokeratins, CEA and CA19-9, while the endocrine element was immunoreactive for chromogranin A and synaptophysin. No immunoreactivity for pancreatic enzymes was noted. Ultrastructural observations showed dense core granules and no zymogen granules. Our case is unique clinically in that the tumor manifested as an intraductal material and no apparent tumor was found by imaging modalities, and pathologically in that the tumor was rare mixed ductal-endocrine carcinoma and the tumor was very small and mainly grew within the main pancreatic duct.

Review of the clinical, histological, and molecular aspects of pancreatic endocrine neoplasms

Pancreatic endocrine neoplasms (PENs) are rare tumors, and little is known about their genetic and chromosomal alterations. Elucidation of the molecular events involved in PEN carcinogenesis has been hindered by the fact that PENs have been considered a single disease entity. The emergence of novel molecular characterization strategies has, however, made it apparent that these lesions exhibit diverse molecular fingerprints, which will facilitate the precise delineation of PEN prognosis, histopathology, and carcinogenesis.

Nonfunctioning islet cell carcinoma of the pancreas

Islet cell cancers of the pancreas may follow an indolent course. Unlike adenocarcinoma of the pancreas, which is considered inoperable for cure in the presence of metastatic disease, islet cell carcinoma of the pancreas in selected cases warrants an aggressive approach toward resection. Significant palliation may be obtained from resection of primary tumors despite the presence of liver metastases. Furthermore, resection or ablation of limited, metastatic disease in the liver may be indicated. Therapeutic decisions must consider the patient's symptoms, coexisting morbidities, and the extent of the disease.

ACTH-secreting islet cell tumor of the pancreas presenting as bilateral ovarian tumors and Cushing's syndrome

A 41-year-old woman presented with hirsutism, a pelvic mass, and Cushing's syndrome. Imaging studies revealed bilateral ovarian masses and a solid and cystic mass within the pancreas. Partial pancreatectomy, bilateral oophorectomy, and excision of several peritoneal tumor nodules were performed. Pathological examination revealed a neuroendocrine islet cell tumor of the pancreas with bilateral ovarian metastases. The tumor was immunoreactive for ACTH, chromogranin, neuron-specific enolase, and keratin. The patient received postoperative chemotherapy and has been disease-free for 6 years. To our knowledge, this is the first reported case of an ACTH-secreting pancreatic neuroendocrine tumor presenting as bilateral ovarian metastases.

Prevalence and prognostic significance of acinar cell differentiation in pancreatic endocrine tumors

We have noted that many histologically and immunohistochemically confirmed pancreatic endocrine tumors show immunophenotypic evidence of acinar cell differentiation, but the clinical relevance of this finding is unknown. We performed this study to evaluate the prevalence and prognostic significance of exocrine differentiation by immunohistochemistry in pancreatic endocrine tumors that do not show morphologic features of acinar cell differentiation. Routinely processed tissue sections from 87 pancreatic endocrine tumors were immunohistochemically stained with monoclonal antibodies against acinar (lipase, chymotrypsin, trypsin) and endocrine cell markers (chromogranin A, neuron-specific enolase, synaptophysin, Leu-7) and for the proliferation-associated peptide Ki67. The degree of staining with each marker was graded on a three-tier scale for acinar markers (grade 0, <5%; grade 1, 5-10%; grade 2, 11-25%; and grade 3, >25%) and on a four-tier scale for endocrine markers (grade 0, <5%; grade 1, 5-25%; grade 2, 26-50%; grade 3, 51-75%; and grade 4, >75%), and the results were correlated with clinical outcome (mean follow-up 53 months). Greater than 75% of the tumor cells stained for chromogranin A, neuron-specific enolase, synaptophysin, and Leu-7 in 100%, 96%, 93%, and 27% of cases, respectively. Overall, 66% of tumors stained positively for at least one acinar cell marker, 31% stained for at least two acinar cell markers, and 13% stained for all three acinar cell markers. Forty-seven percent stained for lipase (23 grade 1, 11 grade 2, seven grade 3), 37% for trypsin (22 grade 1, three grade 2, seven grade 3), and 25% stained for chymotrypsin (13 grade 1, five grade 2, four grade 3). No correlation was noted between the presence or extent of expression of any single or combination of acinar cell markers and clinical outcome. However, higher tumor stage correlated with a poor clinical outcome (p = 0.002), and location in the tail of the pancreas was associated with a longer interval to tumor recurrence (p = 0.03). The presence of synaptophysin (p = 0.03) and Leu-7 expression (p = 0.03) correlated significantly with less aggressive clinical behavior. An association was observed between increased Ki67 labeling and poorer clinical outcome, but this was not statistically significant (p >0.05). In conclusion, immunophenotypic evidence of acinar cell differentiation is common in pancreatic endocrine tumors, but this feature does not have any relevance to clinical prognosis. However, in addition to tumor stage, location in the pancreatic tail and the immunohistochemical expression of synaptophysin and/or Leu-7 may be useful prognostic indicators in patients with these lesions.

Deletion of chromosome 1, but not mutation of MEN-1, predicts prognosis in sporadic pancreatic endocrine tumors

Pancreatic endocrine tumors (PETs) may be sporadic or inherited in the multiple endocrine neoplasia type 1 (MEN-1) syndrome. The inherited form is caused by mutations of the MEN-1 gene, which functions as a tumor suppressor gene and maps to chromosome 11q13. These tumors tend to have a better prognosis than their sporadic counterparts, which often have mutations of the MEN-1 gene. Previous molecular analyses of sporadic PETs suggest a high frequency of loss of heterozygosity (LOH) at chromosome 1 as well as mutation of MEN-1. In this study we correlate abnormalities of MEN-1 and chromosome 1 LOH with the biological behavior of sporadic PETs. Loss of heterozygosity for markers at chromosome 11q13 and mutation of MEN-1 were equally frequent in tumors with or without liver metastases. Mutation of MEN-1 is more frequent in gastrinomas than in non-gastrinomas. Loss of heterozygosity for markers on chromosome 1 is more frequent in PETs with liver metastases. These results suggest a molecular tumor model in which there is a dichotomy in the development of benign and malignant PETs.

Gastric carcinoma resembling pancreatic mixed acinar-endocrine carcinoma

A case of gastric carcinoma resembling pancreatic mixed acinar-endocrine carcinoma of 77-year-old female is presented. This type of gastric tumor has not been previously reported. The endoscopic mucosal resection specimen of the fundus contained a 1.2 x 0.9 x 0.3 cm, well-circumscribed, tan, soft nodular tumor with protruded configuration with a central recess. Histologically, the tumor was confined to the mucosa and submucosa and was characterized by three growth patterns; acinar, solid, and glandular. The growth patterns were intermingled. The tumor cells in the acinar component had round nuclei with prominent nucleoli and diastase-resistant, periodic acid-Schiff-positive, eosinophilic cytoplasm. Immunohistochemically, the tumor cells were positive for CAM5.2, cytokeratin (CK) 7, CK 20, trypsin, lipase, alpha-1-antitrypsin, and alpha-1-antichymotrypsin. The tumor cells in the solid component were positive for Grimelius stain and chromogranin A. The findings indicated that the tumor showed acinar and endocrine differentiation. There was no heterotopic pancreas tissue in the specimen. The patient was well without tumor at the 7-month follow-up. It is important to know the existence of this type of gastric cancer and to not confuse it with a metastatic lesion of the pancreatic origin.

Hepatic artery chemoembolization

Chemoembolization is a technique that can deliver high concentrations of therapeutic agents directly to the liver for prolonged periods. Considerable experience has been gained in the treatment of hepatocellular carcinoma, where it appears to be a safe procedure that provides survival advantage over conservative therapy. There is much less experience in the treatment of hepatic metastases. Patients with carcinoid, pancreatic islet cell tumor, and sarcoma metastatic to the liver do appear to benefit from chemoembolization. Efficacy in other groups, such as patients with colorectal cancer metastatic to the liver, is less well established, but a recently initiated multicenter trial may resolve this issue.

Transformation of the microvascular system during multistage tumorigenesis

Simian virus SV40 large T Antigen expression in the islets of Langerhans of transgenic mice results in beta-cell hyperproliferation, onset of new blood vessel formation and the development of highly vascularized solid tumors. Angiogenesis in the RIPTag mouse model, as well as in human cancer, is a hallmark of multistage tumorigenesis and precedes the development of solid tumors. In our study, intravital microscopy was used to monitor changes in the blood vessel phenotype, microcirculation and leukocyte adhesion during the progression from normal islets to angiogenic islets and solid tumors. In RIP1-Tag5 mice, an aberrant microangioarchitecture becomes apparent in early stages during spontaneous tumor development. Notably, the transition from normal to angiogenic islets is characterized by an increase in vessel diameter rather than vessel numbers. Thus, dilatation of existing vessels precedes vessel sprouting. Once initiated, neovascularization in angiogenic islets results in loss of vessel hierarchy and differentiation. Solid insulinomas display a higher vessel density and even more dramatic vessel heterogeneity as revealed by local "hot spots" of neovascularization and irregular vessel diameters. Strikingly, profound changes in the microangioarchitecture are already observed in early angiogenic islets suggesting that key features of the angiogenic vasculature are established prior to the expansion of tumor mass. Moreover, adhesion of leukocytes was found to be dramatically decreased in both angiogenic islets and solid tumors and correlates with morphological alterations of the vasculature. Thus, vessel transformation and reduced leukocyte-endothelium interactions are not exclusively features of solid tumors but represent early events during tumorigenesis.

[Fluid-fluid level in a non functioning and hemorragic neuro-endocrine islet-cell tumor of the pancreas: MRI features]

The authors report the MR features of a non functioning and hemorragic islet-cell tumor of the pancreas. This tumor was composed of a central cystic component with a fluid-fluid level seen on T1- and T2-weighted images and a peripheral hypervascular soft tissue component which showed hyperintensity on T2-weighted images with fat saturation.

Endocrine tumours of the pancreas: review and recent advances

Pancreatic endocrine tumours (PET) are rare but nonetheless important to recognize and treat in a timely fashion. Significant morbidity occurs due to excess secretion of hormones, with all of the PET having some degree of malignant potential. Surgeons must plan directed operative strategies to deal with these tumours and be prepared to undertake aggressive palliative debulking resections if indicated. Somatostatin receptor scintigraphy and endoscopic ultrasound have been particularly helpful in both localizing and staging patients with PET. Other important advances in management include the use of long-acting somatostatin analogues to inhibit hormonal secretion and tumour growth. The possibility of multiple endocrine neoplasia type 1 (MEN-1) should be considered in any patient with a PET. The present article will review the various classes of PET, describe MEN-1 in relation to PET and examine advances in imaging and localization. The role of surgery for PET is also discussed in the present review.

Induction of pancreatic islet cell tumors in rats by repeated intravenous administration of 4-hydroxyaminoquinoline 1-oxide

The inducibility of pancreatic islet cell tumors by administration of 4-hydroxyaminoquinoline 1-oxide (4HAQO) was investigated in male 6-week-old Sprague-Dawley rats. Rats were given 4HAQO intravenously at a weekly dose of 5 mg/kg 4 times (group 1) or a single dose of 10 mg/kg (group 2). Control rats received the vehicle alone (group 3). Fifty-six weeks after the first 4HAQO administration, all surviving animals were killed and the pancreas was examined histopathologically, immunohistochemically and ultrastructurally. The incidences and multiplicities of islet cell tumors in groups 1, 2, and 3 were 52.3% (p < 0.05 vs group 2, p < 0.01 vs group 3), 19.2% and 0%, and 0.70/animal (p < 0.05 vs group 2, p < 0.01 vs group 3), 0.23 and 0, respectively. Islet cell carcinomas were induced only in group 1, accounting for 6/44 (26%) tumors. Islet cell hyperplasias were found in 61.4% (p < 0.05 vs group 3), 42.3% and 10.0% of groups 1, 2, and 3, with multiplicities of 0.95 (p < 0.05 vs groups 2 and 3), 0.54 and 0.20, respectively. As compared with normal islets from control subjects, islet cell tumors showed an increase in the number of insulin positive cells associated with cytological features indicative of enhanced insulin synthesis and secretion, and a decrease in the number of glucagon positive cells without ultrastructural signs of modified secretory activity. Thus our results indicate that repeated intravenous administration of 4HAQO to rats is useful for the induction of islet cell tumors at high incidence.

Microcytic adenoma coexistent with low-grade malignant islet cell tumor of the pancreas

We report a case of microcystic (glycogen-rich) adenoma of the whole pancreas with coexistent pancreatic low-grade malignant islet cell tumor in a 29-year-old woman. She complained of nausea, vomiting, and growing abdominal mass. Abdominal computed tomography showed multiple cysts in the whole pancreas and a calcified solid mass in the pancreatic head. A Whipple's operation and total pancreatectomy with splenectomy was performed to treat pancreatic cystic neoplasm. The pancreas was entirely replaced by variable-sized, multilocular cysts, which were lined by a flattened-to-cuboidal glycogen-rich epithelium. Furthermore, in the head of the pancreas, a focal yellowish solid mass showed a positive reaction for chromogranin A and neuron-specific enolase. Careful examination of the pancreas is warranted in cases of microcystic adenoma to rule out a possible coexistent pancreatic malignancy.

The effects of ad libitum overfeeding and moderate and marked dietary restriction on age-related spontaneous pancreatic islet pathology in Sprague-Dawley rats

This study compared the effects of ad libitum (AL) overfeeding and moderate or marked dietary restriction (DR) on aged-related degenerative and proliferative changes of the endocrine pancreas in Sprague-Dawley (SD) rats. SD rats were fed Purina Certified Rodent Diet AL (group 1), DR at 72-79% of AL (group 2), DR at 68-72% of AL (group 3) or DR at 47-48% of AL (group 4) for 106 weeks. Interim necropsies were performed at 13, 26, and 53 weeks, after a 7-day 5-bromo-2-deoxyuridine (BrdU)-filled minipump implantation. Before each necropsy, glucose and serum insulin levels were measured. In addition to the routine histopathologic examination performed in both sexes, determination of 9 pancreatic islet stereologic parameters was done in males at 13, 26, and 53 weeks. In AL-fed rats, early changes in the islet morphology occurred, which resulted in a high incidence of islet fibrosis, focal hyperplasias and adenomas by two years. DR was dose-proportionally associated with decreased glucose and serum insulin levels, and delayed the onset, and decreased the incidence and severity of islet fibrosis and hyperplasia. Results of the stereology supported the histopathologic and clinical chemistry findings. It demonstrated that, compared to AL-fed rats, DR-fed rats had smaller pancreas, smaller pancreatic islets, smaller insulin secreting cell volumes, a lower degree of islet fibrosis and a lower islet cell BrdU labeling index, which correlated with a lower incidence of islet adenoma and carcinoma at study termination. Moderate and marked degrees of DR delayed the onset and severity of islet hyperplasia and fibrosis in a temporal- and dose-related manner. In contrast to marked DR, which dramatically prevented these changes, moderate DR delayed but not prevented onset of islet tumors. These findings support the concept that moderate DR results in a better-controlled animal model with a lower incidence or delayed onset of chronic spontaneous endocrine diseases in the rat bioassay.

Malignant islet cell tumor projecting into the main pancreatic duct

We report herein a rare case of islet cell tumor showing a unique growth pattern in a patient who developed repeated acute pancreatitis as the tumor's initial symptom. Preoperative imaging examinations showed dilatation of the main pancreatic duct (MPD) and cysts around the pancreatic tail. A distal pancreatectomy with splenectomy was performed because the pancreatitis was localized in the distal pancreas and was not controlled by various drug therapies. Grossly, the tumor consisted of two component parts: a markedly infiltrative part in the pancreatic parenchyma, and a papillary elevated part in the MPD. The MPD was obstructed by the tumor spreading widely along the distal MPD. Microscopically, the tumor was composed entirely of islet cell tumors (nonfunctioning), with several foci of venous and lymphatic involvement. Based on its growth behavior, we assumed that the tumor may have arisen from the MPD or from islet cells closely adjacent to the MPD. The patient's postoperative course was uneventful and he is doing well 2 years after the operation. We discuss the growth pattern of the tumor and the cause of the pancreatitis.

Successful xenografting of cryopreserved primary pancreatic cancers

In order to assess the suitability of cryopreserved neoplastic tissues for xenografting into nude (nu/nu) mice, we compared the take rate in 28 samples of pancreatic ductal carcinoma. Eleven fresh samples were implanted in nu/nu mice, and 17 were frozen in cryopreserving solution and implanted at a later time. All samples were examined for the presence of neoplastic tissue in cryostat sections. A total of 15 tumors grew in the animals; five from the freshly implanted samples and ten from those cryopreserved. Ten xenografted tumors were characterized for alterations in p53, K-ras, and p16 genes, which were found in six, eight, and nine cases, respectively. Our results demonstrate that the take rate for xenografting is comparable between cryopreserved and fresh tissue samples. The procedure allows for the exchange of tumor material between institutions and permits the establishment of centralized facilities for the storage of an array of different primary tumor samples suitable for the production of in vivo models of cancers.

Chromosomal alterations in human pancreatic endocrine tumors

Comparative genomic hybridization (CGH) was used to investigate changes in DNA copy numbers in 25 paraffin-embedded samples of pancreatic endocrine tumors from 23 patients. Insulin was the dominant hormone in 12, glucagon in 7, somatostatin in 1, and pancreatic polypeptide in 2 tumors. One to 15 (mean, 8.1) changes in DNA copy numbers were observed in 22 of the 25 tumors. The most recurrent aberration, found in 68% of the tumors, involved gains in chromosome 7 with a minimal overlapping region at 7q11.2. Other frequent gains included chromosomes 19 (60%) and 14 (56%). Chromosome arm 20q was amplified in 48% of the cases with the minimal overlapping region of 20q11.1-13.1. The two most frequent DNA losses were found at 11q21-22 in 32% and at 11p13-15 in 24% of the cases. The amplified chromosomal regions contain several candidate genes that may be involved in islet cell tumorigenesis. The regions with most frequent losses are likely to contain still uncharacterized tumor suppressor genes. Wiley-Liss, Inc.

Acinar-islet cell tumor of the pancreas: report of a malignant pancreatic composite tumor

An unusual case of malignant pancreatic composite tumor with both components of acinar cell tumor (ACT) and islet cell tumor (ICT) was investigated histologically, immunohistochemically, and ultrastructurally. The pancreatic tumor with central cyst formation was found on computerized tomographic examination of a 72-year-old man reporting appetite and weight loss. The ACT component was present in the original pancreatic region and the ICT region was adjacent to the ACT. ACT was immunohistochemically positive for pancreatic amylase, whereas ICT had argyrophil tumor cells immunohistochemically positive for chromogranin A. There were several tumor cell nests positive for both pancreatic amylase (acinar differentiation) and chromogranin A (islet differentiation). We speculated that ICT may have arisen from the de-differentiated tumor cells in the ACT after the occurrence of ACT.

Resection of a non-functioning islet cell carcinoma occupying the entire pancreas

A 46-year-old woman with jaundice was found to have enlargement of the entire pancreas on computed tomography. Endoscopy revealed a tumor at the papilla of Vater, although examination of biopsy specimens did not demonstrate a malignancy. The jaundice resolved spontaneously, but reappeared at 7 months. Also noted was increased swelling of the papilla. The serum pancreatic endocrine and exocrine hormone concentrations were within the reference ranges. At surgery, a hard mass was found occupying the entire pancreas. Examination of incisional biopsy specimens from the pancreatic mass and papilla of Vater revealed an islet cell tumor. A total pancreatectomy was performed. The tumor extended from the pancreatic tail to the papilla of Vater. Histopathologic and immunopathologic examination revealed a non-functional islet cell carcinoma. There was no evidence of recurrence at 3 years. A good outcome can be achieved with resection of non-functioning islet cell carcinomas, even if they are advanced.

Hepatoid carcinoma of the pancreas

BACKGROUND

The majority of primary extrahepatic neoplasms exhibiting features of hepatocellular carcinoma in terms of morphology, immunohistochemistry, and behavior have been described in the stomach. To the authors' knowledge only a few cases have involved other organ sites. They frequently are associated with other histologic type tumors such as adenocarcinoma, and portend an aggressive behavior.

METHODS

Two examples of hepatoid carcinoma arising from the pancreas are reported in the current study.

RESULTS

One case was a malignant islet cell tumor with a full-blown clinical syndrome of glucagon overproduction, histologic evidence of hepatocytic differentiation, bile production, and alpha-fetoprotein (AFP) positivity. The second tumor was a ductal carcinoma showing periodic acid-Schiff positive and diastase-resistant hyaline globules, AFP production, and ultrastructural resemblance to hepatocytic cells.

CONCLUSIONS

The rare observation of cellular phenotypic transformation that corresponds with the process of hepatocytic transdifferentiation of pancreatic cells demonstrated in animal models and the common embryologic foregut derivation of the pancreas and liver also may explain the phenomenon of pancreatic hepatoid carcinoma.

Fine needle aspiration diagnosis of neuroendocrine tumors in the liver

Ten neuroendocrine tumors (NET) in the liver are presented, in which the diagnosis was made on fine needle aspiration cytology and cell blocks from the aspirate. In seven of the patients with liver metastasis, a biopsy-proven extrahepatic primary NET had been previously diagnosed, while in three patients no extrahepatic neoplasm could be identified, suggesting that the NET may have been a primary in the liver. Based on cytomorphological findings the cases were typed as either round cell type, spindle cell type or polygonal cell type. In all cases, immunopositivity for neuroendocrine markers provided reliable evidence of the cell of origin and distinguished them from well-differentiated hepatocellular carcinoma, adenocarcinomas and other neoplasms, which sometimes may present a diagnostic dilemma.

Protocol for the examination of specimens from patients with endocrine tumors of the pancreas, including those with mixed endocrine and acinar cell differentiation: a basis for checklists. Cancer Committee of the College of American Pathologists

No Abstract Available

[The establishment of a human pancreatic mixed ductal-endocrine carcinoma cell line]

OBJECTIVE

Establishment of a human pancreatic mixed ductal-endocrine carcinoma cell line.

METHODS

A specimen of this type of cancer was obtained from a male patient at the head of pancreas. The tumor tissue was minced into pieces and inoculated subcutaneously in nude mice. With two successive subcutaneous implants, a piece of tumor tissue taken from the 2(nd) implanted neoplasm of a nude mouse was minced into minute tissue masses and inoculated in a media containing 10% fetal bovine serum.

RESULTS

Currently, it has been passed to the 55(th) passage. Cells of this cell line (PC-EN) kept simultaneously the morphologic patterns of a pancreatic ductal and endocrine tumor which were verified by histochemistry and immunohistochemistry assays. Some of the PC-EN cells showed presence of neuroendocrine granules by electron microscopy. The growth rate of this cell line was relatively low. Kakryotype analysis showed two cell populations with its major mode of chromosomes numbers as 48 in one, and 56 in the other. Study on K-ras gene demonstrated that PC-EN harbored a mutated codon 12. Several gastrointestinal hormones and CEA were detected in PC-EN cells and in the supra-cultured medium using radioimmunoassay.

CONCLUSIONS

The cellular and molecular biologic characteristics of PC-EN cells illustrated that this cell line preserved the morphology of a pancreatic ductal and endocrine tumor and possessed a special growth property, chromosome karyotype, and mutation of Ki-ras gene, but also showed a biologic exocrine and endocrine functions of the pancreas. The establishment of PC-EN cell line will provide a useful model in vitro for further investigating the cellular and molecular biology of exocrine and endocrine tumors of the pancreas.