Pancreatic endocrine tumors

Reprint of: The Diagnostic and Prognostic Utility of Incorporating DAXX, ATRX, and Alternative Lengthening of Telomeres (ALT) to the Evaluation of Pancreatic Neuroendocrine Tumors (PanNETs)

Pancreatic neuroendocrine tumors (PanNETs) are a heterogeneous group of neoplasms with increasing incidence and an ill-defined pathobiology. Although many PanNETs are indolent and remain stable for years, a subset may behave aggressively and metastasize widely. Thus, the increasing and frequent detection of PanNETs presents a treatment dilemma. Current prognostic systems are susceptible to interpretation errors, sampling issues, and do not accurately reflect the clinical behavior of these neoplasms. Hence, additional biomarkers are needed to improve the prognostic stratification of patients diagnosed with a PanNET. Recent studies have identified alterations in death domain-associated protein 6 (DAXX) and alpha-thalassemia/mental retardation X-linked (ATRX), as well as alternative lengthening of telomeres (ALT), as promising prognostic biomarkers. This review summarizes the identification, clinical utility, and specific nuances in testing for DAXX/ATRX by immunohistochemistry and ALT by telomere-specific fluorescence in situ hybridization in PanNETs. Furthermore, a discussion on diagnostic indications for DAXX, ATRX, and ALT status is provided to include the distinction between PanNETs and pancreatic neuroendocrine carcinomas (PanNECs), and determining pancreatic origin for metastatic neuroendocrine tumors in the setting of an unknown primary.

The diagnostic and prognostic utility of incorporating DAXX, ATRX, and alternative lengthening of telomeres to the evaluation of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) are a heterogeneous group of neoplasms with increasing incidence and an ill-defined pathobiology. Although many PanNETs are indolent and remain stable for years, a subset may behave aggressively and metastasize widely. Thus, the increasing and frequent detection of PanNETs presents a treatment dilemma. Current prognostic systems are susceptible to interpretation errors, sampling issues, and do not accurately reflect the clinical behavior of these neoplasms. Hence, additional biomarkers are needed to improve the prognostic stratification of patients diagnosed with a PanNET. Recent studies have identified alterations in death domain-associated protein 6 (DAXX) and alpha-thalassemia/mental retardation X-linked (ATRX), as well as alternative lengthening of telomeres (ALT), as promising prognostic biomarkers. This review summarizes the identification, clinical utility, and specific nuances in testing for DAXX/ATRX by immunohistochemistry and ALT by telomere-specific fluorescence in situ hybridization in PanNETs. Furthermore, a discussion on diagnostic indications for DAXX, ATRX, and ALT status is provided to include the distinction between PanNETs and pancreatic neuroendocrine carcinomas (PanNECs), and determining pancreatic origin for metastatic neuroendocrine tumors in the setting of an unknown primary.

Multiple endocrine neoplasia type 1 (MEN-1) and neuroendocrine neoplasms (NENs)

Neuroendocrine neoplasms (NENs) are relatively rare neoplasms with 6.4-times increasing age-adjusted annual incidence during the last four decades. NENs arise from neuroendocrine cells, which release hormones in response to neuronal stimuli and they are distributed into organs and tissues. The presentation and biological behaviour of the NENs are highly heterogeneous, depending on the organ. The increased incidence is mainly due to increased awareness and improved detection methods both in the majority of sporadic NENs (non-inherited), but also the inherited groups of neoplasms appearing in at least ten genetic syndromes. The most important one is multiple endocrine neoplasia type 1 (MEN-1), caused by mutations in the tumour suppressor gene MEN1. MEN-1 has been associated with different tumour manifestations of NENs e.g. pancreas, gastrointestinal tract, lungs, thymus and pituitary. Pancreatic NENs tend to be less aggressive when arising in the setting of MEN-1 compared to sporadic pancreatic NENs. There have been very important improvements over the past years in both genotyping, genetic counselling and family screening, introduction and validation of various relevant biomarkers, as well as newer imaging modalities. Alongside this development, both medical, surgical and radionuclide treatments have also advanced and improved morbidity, quality of life and mortality in many of these patients. Despite this progress, there is still space for improving insight into the genetic and epigenetic factors in relation to the biological mechanisms determining NENs as part of MEN-1. This review gives a comprehensive update of current evidence for co-occurrence, diagnosis and treatment of MEN-1 and neuroendocrine neoplasms and highlight the important progress now finding its way to international guidelines in order to improve the global management of these patients.

Ectopic insulinoma diagnosed by 68Ga-Exendin-4 PET/CT: A case report and review of literature

RATIONALE

Ectopic insulinomas are extremely rare and challenging to diagnose for clinicians. Precise preoperative localization is essential to successful treatment.

PATIENT CONCERNS

A 23-year-old man presented with a 1-year history of recurrent hypoglycemia.

DIAGNOSIS

Examinations in the local hospital did not reveal any pancreatic lesion. After admission, a fasting test and a 5-hour oral glucose tolerance test (OGTT) suggested a diagnosis of endogenous hyperinsulinemic hypoglycemia. Enhanced volume perfusion computed tomography (VPCT) revealed 2 nodules in the tail of the pancreas, a nodule in the gastric antrum, and a nodule in the hilum of the spleen. To differentiate which nodule was responsible for hypoglycemia, we performed 68Ga-Exendin-4 PET/CT and 68Ga-DOTATATE PET/CT which helped to make a conclusive diagnosis that the lesion in the gastric antrum was an ectopic insulinoma.

INTERVENTIONS

The patient was cured with minimally invasive laparoscopic resection of the tumor.

OUTCOMES

The symptoms were relieved and the blood glucose level remained normal after surgery.

CONCLUSIONS

This case shows that 68Gallium-exendin-4 PET/CT is useful for precise localization and thereby successful treatment of insulinoma, especially for occult insulinomas and those derived from an ectopic pancreas.

The appearance of canine insulinoma on dual phase computed tomographic angiography

OBJECTIVES

To further evaluate the appearance of insulinoma in dogs on dual-phase CT angiography, given the disparity of findings in recent publications. To establish whether CT angiographic localisation of insulinoma correlates with surgical findings.

MATERIALS AND METHODS

Single centre study of dogs with a final diagnosis of insulinoma which underwent abdominal CT angiography. Scans were retrospectively re-evaluated for specific features by two board-certified veterinary radiologists. These findings were also subsequently compared to surgical and histopathological reports to determine the accuracy of lesion localisation on CT.

RESULTS

Thirty-five cases were included in final analysis, with pancreatic nodules identified in 33. Twenty-one were confirmed as insulinoma with histopathology. Jack Russell Terriers were over-represented. Twenty of 21 cases with confirmed insulinoma and 27 of 33 overall showed hyperattenuation in the arterial phase. The mean size of pancreatic insulinoma on CT was 15.1 mm, and 18.2% were larger than 20 mm. Eighteen of 21 confirmed and eight of 12 suspected insulinomas caused a deformation of the pancreatic shape, with two only identified as a result of this feature as these lesions were isoattenuating throughout the study. Pancreatic insulinoma location at surgery matched that described on the CT images in 17 of 19 cases where location was described in the surgical report.

CLINICAL SIGNIFICANCE

In contrast to recent publications, this study suggests hyperattenuation of insulinomas in the arterial phase is a predominant feature, and that hypoattenuation or isoattenuation are much less common. CT angiography is accurate in prediction of lesion location before surgery in most cases.

The added value of intravoxel incoherent motion diffusion weighted imaging parameters in differentiating high-grade pancreatic neuroendocrine neoplasms from pancreatic ductal adenocarcinoma

The aim of the present study was to investigate the potential significance of intravoxel incoherent motion (IVIM)-diffusion weighted imaging (DWI) in differentiating high-grade pancreatic neuroendocrine neoplasms (pNENs) from pancreatic ductal adenocarcinoma (PDAC). A total of 50 patients, including 37 patients with PDAC and 13 patients with high-grade pNENs, underwent pancreatic multiple b-values DWI with 15 b-values including 0, 10, 20, 40, 60, 80, 100, 150, 200, 400, 800, 1,000, 1,200, 1,500 and 2,000 sec/mm². Standard apparent diffusion coefficient (ADC_standard) and IVIM parameter [slow apparent diffusion coefficient (D_slow), fast apparent diffusion coefficient (D_fast), fraction of fast apparent diffusion coefficient (ƒ)] values of PDAC and pNENs were compared. P<0.05 was considered to indicate a statistically significant difference. Receiver operating characteristics analysis was performed in order to evaluate the diagnostic potential of IVIM parameters for differentiating high-grade pNENs from PDAC. D_slow of pNENs was significantly lower compared with that of PDAC (0.460 vs. 0.579×10⁻³ mm²/sec; P=0.001). D_fast of pNENs was significantly higher compared with that of PDAC (13.361 vs. 4.985×10⁻³ mm²/sec; P<0.001). Area under the curve of D_slow, D_fast and combined D_slow and D_fast was 0.793, 0.863 and 0.885 respectively. The specificity and sensitivity of D_slow≤0.472×10⁻³ mm²/sec were 97.3 and 53.9%, respectively, for differentiating high-grade pNENs from PDAC. The specificity and sensitivity of D_fast >9.58×10⁻³ mm²/sec were 91.9 and 69.2%, respectively, for differentiating high-grade pNENs from PDAC. When D_slow and D_fast were combined, the specificity and sensitivity for differentiating high-grade pNENs from PDAC were 76.9 and 100%, respectively. Taken together, these results indicated that the diffusion-associated parameter D_slow and the perfusion-associated parameter D_fast of IVIM-DWI may differentiate high-grade pNENs from PDAC with high diagnostic accuracy, and that IVIM-DWI may be a valuable biomarker in differentiating pancreatic neoplasms.

Pancreatic Polypeptide-Secreting Tumour of the Proximal Pancreas (PPoma)-Ultra Rare Pancreatic Tumour: Clinically Malign, Histologically Benign

Background and objectives: Here we report a rare case of a pancreatic polypeptide-secreting tumour (PPoma) discovered by accident during an autopsy. These PPomas occur in less than 2% of all pancreatic neoplasms and are almost exclusively silent, i.e., they are non-functional. Symptoms arising from PPoma are due to its compression of surrounding tissue. Materials and methods: The autopsy was performed on a 68-year-old male diagnosed with multiple endocrine neoplasm type 1 (MEN1) due to the patient’s sudden death. Results: A solitary, densely fibrotic, pink-brown tumour, 18 mm in size tumorous mass, was localised in the head of the pancreas. Microscopically, the tumour had a glandular structure with a tubuloacinar arrangement of the cells. Immunohistochemically, we detected strong PP (pancreatic polypeptide) intracytoplasmic activity and negative glucagon activity. The PPoma was located in the head of the pancreas, likely resulting in the obstruction of the main pancreatic and common bile duct. Conclusions: To the best of our knowledge, this is the first report suggesting the association of PPomas with MEN1. Also, the PPoma could be the cause of acute hemorrhagic pancreatitis due to its location.

Neoplasms of the Neuroendocrine Pancreas: An Update in the Classification, Definition, and Molecular Genetic Advances

This review focuses on discussing the main modifications of the recently published 2017 WHO Classification of Neoplasms of the Neuroendocrine Pancreas (panNEN). Recent updates separate pancreatic neuroendocrine tumors into 2 broad categories: well-differentiated pancreatic neuroendocrine tumors (panNET) and poorly differentiated pancreatic neuroendocrine carcinoma (panNEC), and incorporates a new subcategory of "well-differentiated high-grade NET (G3)" to the well-differentiated NET category. This new classification algorithm aims to improve the prediction of clinical outcomes and survival and help clinicians select better therapeutic strategies for patient care and management. In addition, these neuroendocrine neoplasms are capable of producing large quantity of hormones leading to clinical hormone hypersecretion syndromes. These functioning tumors include, insulinomas, glucagonomas, somatostatinomas, gastrinomas, VIPomas, serotonin-producing tumors, and ACTH-producing tumors. Although most panNENs arise as sporadic diseases, a subset of these heterogeneous tumors present as parts on inherited genetic syndromes, such as multiple endocrine neoplasia type 1, von Hippel-Lindau, neurofibromatosis type 1, tuberous sclerosis, and glucagon cell hyperplasia and neoplasia syndromes. Characteristic clinical and morphologic findings for certain functioning and syndromic panNENs should alert both pathologists and clinicians as appropriate patient management and possible genetic counseling may be necessary.

The Adult Pancreas in Trauma and Disease

The spectrum of traumatic and natural disease that can affect the adult pancreas is multiple and varied. Some entities are more commonly encountered in routine forensic pathology practice and the forensic pathologist needs to be very familiar with their pathological features and development from a pathophysiological perspective. However, many of the conditions are extremely rare and may never be encountered in the professional lifetimes of an individual pathologist. Still, forensic pathologists need to be aware of them in case they are one day faced with these entities as possible diagnoses to be established at postmortem examination. This can be the result of clinical concerns raised in life, potential natural disease explanations for unexpected biochemical results, and sudden, unexpected or otherwise unexplained deaths where criminal concern about the exogenous administration of a substance must be considered. Acad Forensic Pathol. 2018 8(2): 192-218.

Cross sectional and nuclear medicine imaging of pancreatic insulinomas

Insulinomas are rare neuroendocrine tumors which occur predominantly in the pancreas. Although majority of the insulinomas are benign, over-secretion of insulin by the tumor leads to debilitating hypoglycemic symptoms. The diagnosis is based on clinical and biochemical findings. After the diagnosis is made, the principal challenge lies in locating the tumor because most tumors are solitary and small in size. Locating the tumor is of paramount importance as complete surgical excision is the only curative treatment, and incomplete resection leads to persistence of symptoms. Different preoperative and intraoperative imaging techniques have been used with varying success rates for the insulinoma imaging. Besides localizing the tumor, imaging also helps to guide biopsy, detect metastatic lesions, and perform image-guided therapeutic procedures. This review will discuss the role of different Cross sectional and nuclear medicine imaging modalities in insulinomas.

Pancreatic neuroendocrine tumors: Challenges in an underestimated disease

Pancreatic neuroendocrine tumours (PanNETs) are considered a relatively unusual oncologic entity. Due to its relative good prognosis, surgery remains the goal standard therapy not only in localized disease but also in the setting of locally or metastatic disease. Most of the patients are diagnosed in metastatic scenario, where multidisciplinary approach based on surgery, chemotherapies, liver-directed and/or molecular targeted therapies are commonly used. Owing to a deeper molecular knowledge of this disease, these targeted therapies are nowadays widely implemented, being the likely discovery of predictive biomarkers that would allow its use in other settings. This review is focused on describing the different classifications, etiology, prognostic biomarkers and multidisciplinary approaches that are typically used in PanNET.

64-Slice spiral computed tomography and three-dimensional reconstruction in the diagnosis of cystic pancreatic tumors

The present study aimed to describe the characteristics of cystic pancreatic tumors using computed tomography (CT) and to evaluate the diagnostic accuracy (DA) of post-imaging three-dimensional (3D) reconstruction. Clinical and imaging data, including multi-slice spiral CT scans, enhanced scans and multi-faceted reconstruction, from 30 patients with pathologically confirmed cystic pancreatic tumors diagnosed at the Linyi People's Hospital between August 2008 and June 2014 were retrospectively analyzed. Following the injection of Ultravist® 300 contrast agent, arterial, portal venous and parenchymal phase scans were obtained at 28, 60 and 150 sec, respectively, and 3D reconstructions of the CT images were generated. The average age of the patients was 38.4 years (range, 16-77 years), and the cohort included 5 males and 25 females (ratio, 1:5). The patients included 8 cases of mucinous cystadenoma (DA), 80%]; 9 cases of cystadenocarcinoma (DA, 84%); 6 cases of serous cystadenoma (DA, 100%); 3 cases of solid pseudopapillary tumor (DA, 100%); and 4 cases of intraductal papillary mucinous neoplasm (DA, 100%). 3D reconstructions of CT images were generated and, in the 4 cases of intraductal papillary mucinous neoplasm, the tumor was connected to the main pancreatic duct and multiple mural nodules were detected in one of these cases. The DA of the 3D-reconstructed images of cystic pancreatic tumors was 89.3%. The 64-slice spiral CT and 3D-reconstructed CT images facilitated the visualization of cystic pancreatic tumor characteristics, in particular the connections between the tumor and the main pancreatic duct. In conclusion, the 3D reconstruction of multi-slice CT data may provide an important source of information for the surgical team, in combination with the available clinical data.

Human Insulinomas Show Distinct Patterns of Insulin Secretion In Vitro

Insulinomas are β-cell tumors that cause hypoglycemia through inappropriate secretion of insulin. Characterization of the in vitro dynamics of insulin secretion by perifused fragments of 10 human insulinomas permitted their subdivision into three functional groups with similar insulin content. Group A (four patients with fasting and/or postprandial hypoglycemic episodes) showed qualitatively normal responses to glucose, leucine, diazoxide, tolbutamide, and extracellular CaCl2 omission or excess. The effect of glucose was concentration dependent, but, compared with normal islets, insulin secretion was excessive in both low- and high-glucose conditions. Group B (three patients with fasting hypoglycemic episodes) was mainly characterized by large insulin responses to 1 mmol/L glucose, resulting in very high basal secretion rates that were inhibited by diazoxide and restored by tolbutamide but were not further augmented by other agents except for high levels of CaCl2. Group C (three patients with fasting hypoglycemic episodes) displayed very low rates of insulin secretion and virtually no response to stimuli (including high CaCl2 concentration) and inhibitors (CaCl2 omission being paradoxically stimulatory). In group B, the presence of low-Km hexokinase-I in insulinoma β-cells (not in adjacent islets) was revealed by immunohistochemistry. Human insulinomas thus show distinct, though not completely heterogeneous, defects in insulin secretion that are attributed to the undue expression of hexokinase-I in 3 of 10 patients.

A Single Centre Analysis of Clinical Characteristics and Treatment of Endocrine Pancreatic Tumours

Background. Endocrine Pancreatic Tumours (PENs) are rare and can be nonfunctioning or functioning. They carry a good prognosis overall though high grade lesions show a relatively shorter survival. The aim of the current study is to describe a single centre analysis of the clinical characteristics and surgical treatment of PENs. Patients and Methods. This is a cohort analysis of 40 patients of PENs who underwent surgery at Sir Ganga Ram Hospital, New Delhi, India, from 1995 to 2013. Patient particulars, clinical features, surgical interventions, postoperative outcome, and followup were done and reviewed. The study group was divided based on grade (G1, G2, and G3) and functionality (nonfunctioning versus functioning) for comparison. Results. PENs comprised 6.3% of all pancreatic neoplasms (40 of 634). Twenty-eight patients (70%) had nonfunctioning tumours. Eighteen PENs (45%) were carcinomas (G3), all of which were nonfunctioning. 14 (78%) of these were located in the pancreatic head and uncinate process (P = 0.09). The high grade (G3) lesions were significantly larger in size than the lower grade (G1 + G2) tumours (7.0 ± 3.5 cms versus 3.1 ± 1.6 cms, P = 0.007). Pancreatoduodenectomy was performed in 18 (45%), distal pancreatectomy in 10 (25%), and local resection in 8 (20%) and nonresective procedures were performed in 4 patients (10%). Fourteen patients (35%) had postoperative complications. All G3 grade tumours which were resected had positive lymph nodes (100%) and 10 had angioinvasion (71%). Eight neoplasms (20%) were cystic, all being grade G3 carcinomas, while the rest were solid. The overall disease related mortality attributable to PEN was 14.3% (4 of 28) and for malignant PENs was 33.3% (4 of 12) after a mean follow-up period of 49.6 months (range: 2–137 months). Conclusion. Majority of PENs are nonfunctioning. They are more likely malignant if they are nonfunctioning and large in size, show cystic appearance, and are situated in the pancreatic head. Early surgery leads to good long term survival with acceptable postoperative morbidity.

[Complications of minimally invasive pancreas resection for pancreatic neuroendocrine tumors]

BACKGROUND

Laparoscopic pancreas resections are performed with increasing frequency for pancreatic neuroendocrine tumors and other benign and malignant diseases.

OBJECTIVES

This article describes the complications arising from laparoscopic resection of pancreatic neuroendocrine tumors and compares them to complications arising from similar open procedures.

METHODS

Case series, reports, trials and meta-analyses were analyzed and the results are described and discussed.

RESULTS

The types and the frequencies of complications are comparable for laparoscopic and open resection of pancreatic neuroendocrine tumors. The lack of the ability to perform an intraoperative examination of the pancreas to detect the tumors can be alleviated by laparoscopic ultrasound examination or in the case of tumors expressing somatostatin receptors by preoperative DOTATATE positron emission tomography (PET) computed tomography (CT) scanning.

CONCLUSION

The complications arising from the resection of pancreatic neuroendocrine tumors do not justify a recommendation for a laparoscopic or open approach.

Insulinoma case series: Experience of a tertiary care center

BACKGROUND

Insulinomas are usually solitary; benign and encapsulated small lesions and majority of them measure <2 cm in diameter. They pose a challenge for pre-operative localization. Definitive treatment is surgical excision of the tumor. Intra-operative ultrasonography (IOUS), transhepatic portal venous sampling (THPVS) and positron emission tomography (PET) scan can be done for tumors not localized by conventional imaging modalities.

MATERIALS AND METHODS

A retrospective study of patients diagnosed with insulinoma during the period 2004-2012 (8 years) was done. Biochemical diagnostic criteria used were plasma concentrations of glucose <55 mg/dl with corresponding insulin level >3.0 μU/ml (18 pmol/L) and C-peptide of >0.6 ng/ml (0.2 nmol/L). The localization of the tumor was done by various modalities namely computed tomography (CT), magnetic resonance imaging (MRI), IOUS, PET and portal venous sampling. The initial localizing technique in most of these patients were CT or MRI imaging, or both and those who were not localized by the above modalities were subjected to PET CT or THPVS or intra-operative ultrasound depending on the initial imaging results and patient's consent. All the modalities were not used in the same patient, but the modalities were decided as per the imaging results, patient's consent and affordability for the procedure.

RESULTS

Ninteen cases of insulinoma aged between 10 and 66 years, with a median age of 47 years were included in the analysis. There were 10 males and nine females. Eighty-three percent of patients presented with pre-prandial hypoglycemia (n = 15). Different modalities were employed for pre-operative localization of these patients out of which 5 (26.31%) cases were localized with CT, 5 (26.31) cases with MRI, 5 (26.31%) with THPVS, 1 (5.26%) case with PET CT, 3 (15.78%) of them could not be localized out of which 2 (10.52%) were localized by IOUS and 1 (5.26%) case the lesion could not be localized. Among 19 cases, 12 underwent surgery out of which one patient underwent distal pancreatectomy as tumor was not localized; eight underwent laparoscopic enucleation; three of them required intra-operative exploration and seven of them were not operated, as they did not give consent for surgery. In all the cases, the size of the insulinoma ranged between 1 and 2 cm.

CONCLUSION

We report our experience with 19 cases of insulinoma and analyze the role of pre- and intra-operative imaging modalities in the surgical management of insulinomas. Most of our cases were symptomatic, and the most common presentation was with pre-prandial hypoglycemia. THPVS, PET scan and intra-operative ultrasound added to diagnostic sensitivity in some cases not localized by CT or MRI.

A case of nonfunctioning pancreatic endocrine tumor with atypical imaging findings due to prominent fibrosis of the tumor stroma

The patient, a 56-year-old woman, was found during routine checkup to have a disorder of hepatic function. Abdominal ultrasonography showed an ill-defined hypoechoic mass in the head and body of the pancreas; however, no blood-flow signal was observed within the tumor on Doppler ultrasonography. Abdominal computed tomography showed a low-density area in the arterial and portal venous phases. The lesion was visualized as an area of low signal intensity on both T1- and T2-weighted magnetic resonance images, whereas fluorodeoxyglucose positron emission tomography showed fluorodeoxyglucose accumulation in the tumor. Although a preoperative diagnosis was difficult to make, a rapid cytologic examination revealed evidence of a pancreatic endocrine tumor, and subtotal stomach-preserving pancreaticoduodenectomy with portal vein resection was performed. Histopathological examination showed tumor cell nests scattered in abundant fibrotic tissue; the tumor cells had proliferated in a cord-like fashion and showed immunostaining for chromogranin A. Staining for fibroblast activation protein α was seen in the fibroblastic cells contained within the fibrous stroma surrounding the tumor cell nests, whereas both the fibroblastic cells in the tumor and those in the stroma showed a high rate of staining for thrombospondin. We presume that tumor-associated fibroblasts were involved in the fibrosis of the tumor stroma.

Insulinoma: rare yet important

We report our experience with six cases of insulinoma that were managed at our hospital between 2009 and 2013. Four patients were women and two men, with mean age of 43 years and mean duration of symptoms before diagnosis of 5.7 years. Biochemical confirmation was made in all cases and preoperative localisation was successful in two cases only. In the other four, intraoperative localisation was made. Enucleation was performed in four patients and distal pancreatectomy in the other two. The tumour was proved benign in all patients by histopathology. Postoperatively, all patients were asymptomatic during a follow-up period ranging from 9 months to 4 years and both serum glucose and insulin were normal during that period. We think that careful preoperative workup and skilful surgical techniques can end the prolonged suffering of patients with insulinomas with excellent results.

Pancreatic endocrine tumors

Pancreatic endocrine tumours are rare tumours, and arise from the types of pancreatic cells that produce hormones. These tumours may or may not secrete hormones themselves and may or may not be cancerous (malignant). Functioning tumours secrete a particular hormones which may cause various syndromes. The present article reviews the latest reports on the pancreatic endocrine tumours.

Incidental intraoperative discovery of a pancreatic neuroendocrine tumor associated with chronic pancreatitis

Pancreatic neuroendocrine tumors are a rare entity with an incidence between 2 per million to 5 per 100,000. Association with pancreatitis (acute or chronic) is rare and is considered to be determined by the tumoral obstruction of pancreatic ducts, but sometimes occurs without any apparent relationship between them. Non-functional neuroendocrine pancreatic tumors are usually diagnosed when either very large or metastatic. Small ones are occasionally diagnosed when imagery is performed for other diagnostic reasons. Intraoperative discovery is even rarer and poses problems of differential diagnosis with other pancreatic tumors. Association with chronic pancreatitis is rare and usually due to pancreatic duct obstruction by the tumor. We describe the case of a patient with a small non-functioning neuroendocrine tumor in the pancreatic tail accidentally discovered during surgery for delayed traumatic splenic rupture associated with chronic alcoholic pancreatitis. The tumor of 1.5 cm size was well differentiated and confined to the pancreas, and was resected by a distal splenopancreatectomy.

CONCLUSIONS

Surgeons should be well aware of the rare possibility of a non-functional neuroendocrine tumor in the pancreas, associated with chronic pancreatitis, surgical resection being the optimal treatment for cure. Histopathology is of utmost importance to establish the correct diagnosis, grade of differentiation, malignancy and prognosis.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2114470176676003.

Pancreatic endocrine neoplasms: a current update on genetics and imaging

Pancreatic endocrine neoplasms are rare pancreatic tumours that may occur sporadically or as part of inherited syndromes such as multiple endocrine neoplasia-1 syndrome, von Recklinghausen disease, von Hippel-Lindau syndrome and tuberous sclerosis complex. Recent advances in the genetics and pathology of hereditary syndromes have provided valuable insights into the pathophysiology and biology of sporadic pancreatic endocrine neoplasms. Evolving molecular data on the biology of these neoplasms have the potential for diagnostic, therapeutic and prognostic use.

Outcome after laparoscopic enucleation for non-functional neuroendocrine pancreatic tumours

BACKGROUND

Non-functional endocrine pancreatic tumours (NPT) of more than 2 cm have an increased risk of malignancy. The aim of the present study was: (i) to define the guidelines for laparoscopic enucleation (LapEn) in patients with a non-functional NPT ≤3 cm in diameter; (ii) to evaluate pancreas-related complications; and (iii) to present the long-term outcome.

METHODS

Between April 1998 and September 2010, 30 consecutive patients underwent laparoscopic surgery for a non-functional NPT (median age 56.5 years, range 44-83). Only 13 patients with tumours ≤3 cm in size underwent LapEn. Local lymph node dissection to exclude lymph node involvement was performed in all patients.

RESULTS

The median tumour size, operative time and blood loss were 2.8 cm (range 2.8-3), 130 min (range 90-280) and 220 ml (range 120-300), respectively. A pancreatic fistula occurred in five patients: International Study Group of Pancreatic Fistula (ISGPF) A in two patients and ISGPF B in three patients. The median follow-up was 48 months (12-144). Three patients with well-differentiated carcinoma are free of disease 2, 3 and 4 years after LapEn and a regional lymphadenectomy. One patient, 5 years after a LapEn, presented with lymph node and liver metastases.

CONCLUSIONS

The present study confirms the technical feasibility and acceptable morbidity associated with LapEn. Intra-operative lymph node sampling and frozen-section examination should be performed at the time of LapEn; when a malignancy is confirmed, oncologically appropriate lymph node dissection should be performed.

Preoperative tumor studies using MRI or CT in patients with clinically suspected insulinoma

PURPOSE

Insulinomas are rare tumors that originate from the islet cells of the pancreas. The aims of this study were to localize insulinomas preoperatively using CT and/or MRI in correlation with postoperative pathological results.

PATIENTS AND METHODS

Between December 2001 and June 2010, 27 consecutive patients with clinically suspected insulinoma were surgically treated in our university hospital. Preoperative CT (14 of 27 patients) and MRI studies (14 of 27 patients, one patient had both MRI and CT), operation reports, intraoperative ultrasonography reports, and pathological diagnoses were analyzed retrospectively. For each lesion, images were analyzed based on the presence of enhancement or the characteristics of signal intensities. Pathologic correlation was available for all the lesions.

RESULTS

The female: male ratio was 2.9, with a mean age of 47.5 years (range 12-82) . Preoperative tumor localization was achieved by means of MRI and CT. A focal pancreatic lesion, which was hypointense on T(1)-weighted sequences, was detected on all the MR images (14 of 27 patients; 100%). These lesions were isointense (4 cases) to slightly hyperintense (10 of 14 cases) on T(2)-weighted sequences. In T(1)-weighted fat-suppressed contrast-enhanced sequences, there were two types of enhancement: homogeneously hyperintense lesions (in 10 of 14 cases) or peripherally hyper-, centrally isointense (in 4 of 14 cases). On all the CT images (14 of 27 patients), there was no detectable lesion on precontrast series; on arterial series in 13 of 14 patients (arterial series has not been done in one patient), lesions enhanced hypervascular in contrast to the rest of the pancreas with a mean enhancement of 147 HU (range 113-248) and 95 HU (range 65-141), respectively. On venous series in 13 of 14 patients (venous series has not been done in one patient), there was an enhanced lesion in contrast to the rest of the pancreas with a mean enhancement of 110 HU (range 91-151) and 86 HU (range 65-137), respectively. Intraoperative ultrasonography was performed in 11 of 27 patients to localize the tumor, which correlated with the results of the mentioned preoperative studies. Tumor size ranged from 9 × 11 to 31 × 37 mm. Enucleation was carried out in 14 patients, Whipple in 5, segmental resection in 3 and left distal pancreatectomy in 5 patients. The mortality rate was 0. Pathological findings were insulinoma or neuroendocrine tumors in 26 of 27 cases. One patient had a pathological finding of chronic pancreatic disease with intraepithelial neoplasia (grade 1A).

CONCLUSION

We conclude that the preoperative localization of insulinoma in clinically suspected patients can be made on the basis of MRI and/or CT studies. A hallmark lesion is hypointense in T(1)-weighted sequences, homogeneously or peripherally hyperintense in T(1)-weighted fat-suppressed contrast-enhanced sequence using MRI (100% of cases) or/and a hypervascular enhanced lesion on arterial (100% of CT studies) and on venous series using CT (66.7% of CT studies).

Imaging of neuroendocrine tumors

Neuroendocrine tumors (NETs) constitute a large group of diverse neoplasms with a wide spectrum of clinical, imaging, and pathologic findings. Imaging diagnosis of NETs can be challenging, and several complementary imaging modalities may be needed during the diagnostic workup. Accurate interpretation of the imaging findings is important to facilitate diagnosis and contribute to patient management. This article discusses the gastrointestinal site-specific features and the tumor-specific features of several NETs and the role of several imaging modalities such as computed tomography, MR imaging, ultrasonography, and positron emission tomography in the evaluation of these NETs.

Pancreatic neoplasia: a practical cross-sectional imaging primer for the nonradiologist

PURPOSE

The purpose of this article is to provide a practical review of basic pancreatic imaging protocols and key cross-sectional imaging findings of the more common pancreatic neoplasms.

METHODS

We performed a literature search and reviewed numerous cases archived in the radiology department of a large university hospital to find examples which illustrate the key cross-sectional imaging findings of pancreatic neoplasms.

RESULTS

We reviewed the literature and provided several practical examples of common cross-sectional imaging findings in patients with pancreatic neoplasms.

CONCLUSIONS

Cross-sectional imaging plays a pivotal role in the evaluation of pancreatic neoplasms and allows proper triage of patients for conservative, medical or surgical management due to its ability to reliably detect and characterize pancreatic lesions, determine involvement of local structures, and assess metastatic disease. Familiarity with the key imaging findings will allow the clinician to better implement imaging data into daily practice.

Value of both WHO and TNM classification systems for patients with pancreatic endocrine tumors: results of a single-center series

OBJECTIVES

This study was designed to evaluate the clinical relevance of the World Health Organization (WHO) and tumor node metastasis (TNM) classifications in patients affected by pancreatic endocrine tumors.

METHODS

Data from 76 consecutive patients with pancreatic endocrine tumors who underwent surgery were analyzed.

RESULTS

Well-differentiated tumors were observed more frequently (57.9%) than well or poorly differentiated carcinomas (26.3% and 15.8%, respectively). The TNM stage was I in 27.6%, II in 39.5%, III in 19.7%, and IV in 13.2%. Univariate analysis of disease-specific survival showed that patients with stages I-II had a significantly better survival rate than those with stages III-IV (hazard ratio (HR), 12.46; 95% confidence interval (CI), 1.53-101.32; P = 0.018; HR, 25.74; 95% CI, 3.07-216.07; P = 0.003, respectively). Regarding the WHO classification, poorly differentiated carcinomas had the worst prognosis (HR, 79.13; 95% CI, 9.99-626.60; P < 0.001). Multivariate Cox regression analysis of disease-specific survival showed that the WHO classification is the only independent factors of improved survival: both poorly and well-differentiated carcinomas had an increased risk of death compared with WDTs (HR, 100.42; 95% CI, 12.16-829.40; P < 0.001; HR, 10.73; 95% CI, 1.12-104.17; P = 0.040, respectively). TNM classification and the WHO system are highly correlated (P < 0.001).

CONCLUSIONS

TNM stage and the WHO classification seems to be equally reliable, even if TNM classification tends to understage the patients classified using the WHO system.

Clinical profile of insulinoma: analysis from a tertiary care referral center in India

OBJECTIVE

To describe the clinical presentation, localization techniques, surgical procedures and outcome in patients with insulinoma.

METHODS

Retrospective analysis of case records of patients diagnosed with insulinoma between January 1993 and June 2009 at a tertiary-care hospital was done. Seventeen patients underwent diagnostic 72-h fast. The sensitivity of computed tomography (CT) of pancreas was judged using intraoperative findings as the gold standard.

RESULTS

Twenty-six patients (19 women) with mean age 42.2 years (median age 39.5 years) with biochemical/imaging evidence of insulinoma were included. All patients who underwent 72-h fast developed symptomatic hypoglycemia within 48 h. The sensitivity and positive predictive value (PPV) of CT of pancreas was 68.4% and 92.8%, respectively. Twenty patients underwent surgery, of whom four were operated on without preoperative localization. Four patients had recurrence of symptoms. Of the six patients who were not operated upon, the lesion was localized in four.

CONCLUSION

This audit shows that all patients with insulinoma develop hypoglycemia within 48 h of fasting. CT of pancreas localizes the lesion in two thirds of cases and would be a useful initial investigation in patients with suspected insulinoma.

Increased expression of CD44v6 in endocrine pancreatic tumours but not in midgut carcinoid tumours

Aims/background-To analyse the different isoforms of CD44 in various types of endocrine pancreatic and gut carcinoid tumours and to investigate the relation between their expression and tumour dissemination. This study was prompted by the recent observation that inappropriate splicing of the CD44 gene was correlated with tumour progression and metastasis formation in a number of human cancers.Methods-Expression of CD44 isoforms was studied in 38 endocrine pancreatic tumours and gut neuroendocrine tumours using antibodies directed against products of exons v3, v4-v5, v6, v7-v8 as well as against the standard CD44 molecule (CD44H). CD44 gene expression was also analysed by reverse transcription PCR (RT-PCR) in nine endocrine and seven carcinoid tumours.Results-All gastrinomas except one (nine of 10) and about half of the other endocrine pancreatic tumours (seven of 15) expressed CD44v6. Most (10/11) midgut carcinoid tumours were CD44v6 negative, with no detectable immunostaining. CD44v3, CD44v4-v5 and CD44v7-v8 were not expressed in any of these tumours. CD44 mRNA analysis illustrated a complex splice pattern and expression of large CD44 isoforms in CD44v6 positive endocrine tumours, whereas the standard form only was detected in midgut carcinoid tumours. No correlation between CD44 variant expression and tumour metastasis was observed.Conclusions-CD44 variants encoding exon v6 are preferentially expressed both in gastrinomas and in most pancreatic endocrine tumours. In contrast to other tumours, the expression of CD44v6 in pancreatic neuroendocrine tumours does not seem to be correlated with tumour dissemination.

EUS for pancreatic neuroendocrine tumors: a single-center, 11-year experience

BACKGROUND

Pancreatic neuroendocrine tumors (PNTs) are rare tumors with malignant potential. EUS and EUS-guided FNA (EUS-FNA) have been shown to be superior to other imaging methods in the preoperative localization and diagnosis of PNTs.

OBJECTIVES

To evaluate the clinical presentation, EUS morphology, and sensitivity of EUS-FNA cytology in a large consecutive cohort with histologically and/or cytologically confirmed PNTs.

DESIGN

Retrospective study of all consecutive patients from July 1995 to November 2006 who underwent EUS for a known or suspected PNT and had a subsequently histologically confirmed PNT.

SETTING

Tertiary referral center.

PATIENTS

Ninety-two patients with suspected PNT.

INTERVENTIONS

EUS evaluation with or without EUS-FNA of PNTs.

MAIN OUTCOME MEASUREMENTS

Clinical and EUS features of PNTs and sensitivity of EUS-FNA for the diagnosis of PNTs.

RESULTS

Ninety-two patients underwent EUS; 76 patients had confirmed histopathology, of whom 69 (91%) were symptomatic. Patients with functional PNTs presented with diarrhea, peptic ulcer disease, and hypoglycemia. Tumor locations and echogenic features were similar except that nonfunctional PNTs tended to be larger and have cystic features. Patients with malignant PNTs were older (P = .03), presented with abdominal pain, and had larger tumors (P = .0006) with irregular margins. Eighty-nine percent of patients underwent EUS-FNA. Sensitivity of EUS-FNA for the diagnosis of a PNT was 87%. Sensitivity of EUS-FNA was similar in functional and nonfunctional PNTs. The sensitivity of EUS-FNA was higher for malignant PNTs (P = .008).

LIMITATIONS

Retrospective single tertiary center.

CONCLUSIONS

EUS and EUS-FNA are sensitive tools, especially in cases of suspected symptomatic PNTs in which other imaging modalities have failed.

Giant Insulinoma in Uncinate Region Treated by Enucleation

A 32-year-old male patient, a known case of chronic myeloid leukemia (CML) with 11 × 9 cm GIANT functioning insulinoma in the uncinate region of pancreas, with no local invasion or metastatic disease, is presented. In view of CML, enucleation of the tumor done. Histopathology was s/o ‘insulinoma of uncertain biological behavior’. Postoperatively, the patient was followed up for one year and found normal.

Neuroendocrine tumors of the pancreas

Pancreatic endocrine tumors are rare neoplasms accounting for less than 5% of pancreatic malignancies. They are broadly classified into either functioning tumors (insulinomas, gastrinomas, glucagonomas, VIPomas, and somatostatinomas) or nonfunctioning tumors. The diagnosis of these tumors is difficult and requires a careful history and examination combined with laboratory tests and radiologic imaging. Signs and symptoms are usually related to hormone hypersecretion in the case of functioning tumors and to tumor size or metastases with nonfunctioning tumors. Surgical resection remains the treatment of choice even in the face of metastatic disease. Further development of novel diagnostic and treatment modalities offers potential to greatly improve quality of life and prolong disease-free survival for patients with pancreatic endocrine tumors.

Neuroendocrine tumors of the pancreas

This literature review briefly summarizes the epidemiology, pathophysiology, clinical management, and outcomes of patients with pancreatic neuroendocrine tumors (PNETs) and highlights recent advances in PNET research. PNETs are rare neoplasms, compared with carcinomas arising from pancreatic exocrine tissue. They, like other neuroendocrine tumor types, display variable malignant potential, hormone-related syndromes (functionality), localization, and genetic background. Although tumor origin and molecular pathogenesis remain poorly understood, recently established grading and staging systems facilitate patient risk stratification, and thereby directly impact clinical decision making. Although the optimal clinical management of PNETs involves a multidisciplinary approach, surgery remains the only curative treatment for early-stage disease. Surgery may also have a role in patients with advanced-stage disease, including those with hepatic metastases. Alternative therapeutic approaches applied to PNETs, including chemotherapy, radiofrequency ablation, transarterial chemoembolization, biotherapy, polypeptide radionuclide receptor therapy, antiangiogenic therapy, and selective internal radiotherapy, have failed to demonstrate a long-term survival benefit. Surgery remains the primary therapeutic option for patients with PNETs. Research on PNETs is desperately needed to improve the therapeutic options for patients with this disease.

Nonfunctioning neuroendocrine pancreatic tumors: our experience and management

BACKGROUND AND PURPOSE

We present our experience in the treatment of nonfunctioning neuroendocrine pancreatic tumors (NFNPTs) to define the clinical and pathological characteristics and to suggest proper management.

METHODS

The records of 17 patients with NFNPTs operated on between 1998 and 2008 were retrospectively reviewed, and all tumors were classified clinicopathologically as benign, uncertain, and malignant, based on the World Health Organization (WHO) classification of neuroendocrine tumors.

RESULTS

There were four benign, six uncertain, and seven malignant NFNPTs. The most frequent symptoms were abdominal pain (five patients) and obstructive jaundice (one patient). Most of these symptomatic patients had malignant tumors. Mean tumor size of benign, uncertain, and malignant tumors were 1.0 +/- 0.3, 3.2 +/- 1.6, and 5.3 +/- 2.4 cm, respectively. Metastatic lesions of malignant tumors were lymph node (six patients), liver (four patients), and adrenal gland (one patient). Six of seven patients with malignant tumors underwent curative rejection. There were recurrences in four of six patients with curatively rejected malignant tumors. Two patients underwent more rejection, three patients received systemic chemotherapy, and two patients underwent radiofrequency ablation and transcatheter arterial chemoembolization for liver metastases. Survival of patients with malignant tumors was significantly shorter than that of patients with benign and uncertain tumors. However, three patients with malignant tumors had long survival of more than 3 years, even with metastases or recurrences.

CONCLUSIONS

Aggressive surgical resection should be performed in patients with resectable NFNPTs, even with metastases. Even when a tumor was unresectable or there were recurrences, long-time palliation could be achieved by a multidisciplinary approach.

Survival and prognostic factor analysis in patients with metastatic pancreatic endocrine carcinomas

OBJECTIVES

Pancreatic endocrine carcinomas (PECAs) are uncommon, with an incidence of 1 per 100,000. Past studies of chemotherapy and hepatic arterial embolization have described median survival durations of approximately 2 to 3 years. Overall survival from time of diagnosis of metastases has never been reported in a large cohort of patients. Our objective was to evaluate the stage-specific prognosis of patients with metastatic PECAs and to assess the impact of clinical and pathologic prognostic factors.

METHODS

We evaluated all cases of differentiated, metastatic PECAs seen at the H. Lee Moffitt Cancer Center between the years 1999 and 2003, measuring survival from time of diagnosis of metastases.

RESULTS

Ninety cases of metastatic PECAs were identified. Median overall survival was 70 months, and the 5-year survival rate was 56%. Age, sex, and tumor type (functional vs nonfunctional) did not impact prognosis. Tumor grade, however, was highly prognostic for survival.

CONCLUSIONS

Median overall survival is 70 months (5.8 years) among patients with metastatic PECAs. This prolonged survival duration may reflect the impact of multimodality treatments. Tumor grade (low vs intermediate grade) represents a highly significant prognostic factor.

TRPA1 regulates gastrointestinal motility through serotonin release from enterochromaffin cells

Serotonin (5-hydroxytryptamine; 5-HT) is abundantly present throughout the gastrointestinal tract and stored mostly in enterochromaffin (EC) cells, which are located on the mucosal surface. 5-HT released from EC cells stimulate both intrinsic and extrinsic nerves, which results in various physiological and pathophysiological responses, such as gastrointestinal contractions. EC cells are believed to have the ability to respond to the chemical composition of the luminal contents of the gut; however, the underlying molecular and cellular mechanisms have not been identified. Here, we demonstrate that the transient receptor potential (TRP) cation channel TRPA1, which is activated by pungent compounds or cold temperature, is highly expressed in EC cells. We also found that TRPA1 agonists, including allyl isothiocyanate and cinnamaldehyde, stimulate EC cell functions, such as increasing intracellular Ca(2+) levels and 5-HT release, by using highly concentrated EC cell fractions and a model of EC cell function, the RIN14B cell line. Furthermore, we showed that allyl isothiocyanate promotes the contraction of isolated guinea pig ileum via the 5-HT(3) receptor. Taken together, our results indicate that TRPA1 acts as a sensor molecule for EC cells and may regulate gastrointestinal function.

The impact of preoperative endoscopic ultrasound on the surgical management of pancreatic neuroendocrine tumours

BACKGROUND

Endoscopic ultrasound (EUS) is accurate in diagnosing pancreatic neuroendocrine tumours (PNETs), but its impact on surgical management is unclear.

OBJECTIVE

To determine whether preoperative EUS findings altered the decision for, and extent of, surgery in patients with PNETs.

METHODS

A retrospective review of patients referred for EUS because of suspected PNETs was conducted. The diagnosis of PNETs was confirmed by EUS-guided fine needle aspiration cytology, where indicated, or by surgical histology. EUS findings were compared with computed tomography (CT) findings to determine whether there was an impact on the decision for surgical management.

RESULTS

Fourteen patients (10 women), with a mean age of 44 years, underwent EUS for suspected PNETs. PNETs were seen with CT in 10 of 13 patients (77%) and with EUS in 14 of 14 patients (100%). One obese patient could not fit into the CT scanner. This patient had five PNETs on EUS. Three patients with a normal CT scan were determined to have one or two PNETs on EUS. Three patients with one or two PNETs on CT were found to have five to eight PNETs on EUS. EUS altered the decision for possible surgical management in five of 14 patients (36%), either by identifying a PNET or by finding multiple and multifocal PNETs that were not visualized on CT scans.

CONCLUSION

EUS is useful in the preoperative assessment of PNETs by providing information that significantly influences the decision for surgical intervention or changes the extent of the planned surgery.

Pancreatic neuroendocrine tumors (PNETs): incidence, prognosis and recent trend toward improved survival

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) are uncommon neoplasms that can present with symptoms of hormone overproduction. We evaluated the incidence, prognosis, and temporal trends of PNETs.

PATIENTS AND METHODS

We analyzed all cases of PNETs registered in the Surveillance, Epidemiology, and End Results database from 1973 to 2000. Age-adjusted incidence and survival rates were calculated and survival trends over time were evaluated.

RESULTS

We identified 1483 cases of PNETs. The crude annual incidence per 1,000,000 was 1.8 in females and 2.6 in males and increased with advancing age. The incidence increased over the study period. Most patients (90.8%) had nonfunctional tumors. Advanced stage, higher grade, and age were the strongest predictors of worse survival. Patients with functional tumors had better outcomes than patients with nonfunctional tumors in both univariate and multivariate analysis (P = 0.004). Survival time increased over the period from 1973 to 2000. No differences were seen in the distribution of stage or age at diagnosis among time periods.

CONCLUSION

PNETs are uncommon neoplasms but the incidence may be increasing. Age, grade, stage, and functional status predict survival in patients with PNETs. Survival has improved over time, but this is not explained by earlier diagnosis or stage migration.

Pancreatic endocrine neoplasms: epidemiology and prognosis of pancreatic endocrine tumors

Pancreatic endocrine tumors (PETs) are uncommon tumors with an annual incidence <1 per 100 000 person-years in the general population. The PETs that produce hormones resulting in symptoms are designated as functional. The majority of PETs are non-functional. Of the functional tumors, insulinomas are the most common, followed by gastrinomas. The clinical course of patients with PETs is variable and depends on the extent of the disease and the treatment rendered. Patients with completely resected tumors generally have a good prognosis, and aggressive surgical therapy in patients with advanced disease may also prolong survival. The epidemiology, prognosis, and established and novel prognostic markers of PETs are reviewed.

Pancreatic endocrine tumors-c-erb B2 (Her-2/neu), bcl-2, and p-53 immunohistochemical testing and their value in assessing prognosis

INTRODUCTION

In an attempt to identify better prognostic factors, and the genetic basis of pancreatic endocrine tumors (PETs), we evaluated immunohistochemical reactivity for c-erb B2 (Her-2/neu), bcl-2, and p53.

METHODS AND MATERIALS

Two pathologists reviewed hematoxylin and eosin slides and immunohistochemical stains from 28 cases, 27 tumors and 1 nesidioblastosis. Using WHO criteria for malignancy (presence of local or lymphovascular invasion and/or metastases), cases were divided into malignant (20 cases) and benign or uncertain (8 cases). Nuclear staining in >1% of cells was considered positive for p53 and bcl-2, whereas membranous staining was considered positive for c-erb B2 (Her-2/neu).

RESULTS

All cases were nonimmunoreactive with anti-c-erb B2 (Her-2/neu), but focal granular or diffuse cytoplasmic staining was seen in occasional neoplasms. One malignant PET showed reactivity with anti-p53, whereas all others were negative. bcl-2 reactivity was identified in 15/28 cases: 9/20 malignant PETs and 6/8 others were positive.

CONCLUSIONS

c-erb B2 (Her-2/neu) and p53 are not useful prognostic factors in PET. c-erb B2 (Her-2/neu) staining must be carefully evaluated to avoid the misinterpretation of artifactual/background staining. bcl-2 is occasionally expressed in PET, but the significance of this finding is still to be determined.

Pancreatic neuroendocrine tumours

Pancreatic neuroendocrine tumours (PET) are rare neoplasms of the pancreas accounting for less than 5% of all primary pancreatic malignancies. Included in this group are insulinomas, gastrinomas, glucagonoma and somatostatinomas. Collectively these neoplasms are classified as functional PETs. Where a PET is not associated with a clinical syndrome due to hormone oversecretion, it is referred to as a non-functioning PET. Non-functioning PETs are pancreatic tumours with endocrine differentiation but lack a clinical syndrome of hormone hypersecretion. The incidence of these tumours varied between 15 and 53%. Presentation is related to the mass effect of the tumour with symptoms often non-specific. Treatment is surgical excision with chemotherapy and hormonal therapy is controversial. For functioning PETs, surgery remains the optimal therapy, however, long-term survival can be expected even in the presence of metastases. With advances in medical management, radiolabelled somatostatin therapy, hepatic arterial chemoembolisation and radiofrequency ablation, symptoms may be controlled to optimize quality of life.

Site-specific biology and pathology of gastroenteropancreatic neuroendocrine tumors

The gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are composed of cells with a neuroendocrine phenotype. Well-differentiated tumors, well-differentiated carcinomas, poorly differentiated carcinomas, functioning tumors (with a hormonal syndrome), and nonfunctioning tumors are identified. To predict their clinical behavior, these neuroendocrine tumors are classified on the basis of their clinicopathological features, including size, local invasion, angioinvasion, proliferative activity, histological differentiation, and metastases, into neoplasms with benign, uncertain, low-grade malignant and high-grade malignant behavior. In addition, a tumor/nodes/metastases classification and a grading system are presented. In the light of these criteria, the various GEP-NET entities are reviewed.

The role of angiogenesis in endocrine liver metastases: an experimental study

Liver metastases are a major adverse event during the evolution of digestive endocrine tumors. However, little is known about their natural history and the determinants of their growth. In particular, whereas liver endocrine metastases, like their primary counterparts, are hypervascular, the role of tumor-associated angiogenesis has been little explored. We therefore designed an experimental model to study the intrahepatic growth of tumor endocrine cells; murine enteroendocrine STC-1 cells were injected into the spleen of nude mice to obtain their hepatic dissemination through the portal vein. Three stages of intrahepatic tumor growth were identified. Engraftment stage, until day 4 after intrasplenic injection of STC-1 cells, was avascular. Early growth, until day 17, resulted in small, infralobular nodules. Late growth, after day 17, was characterized by the development of large nodules associated with peritumoral vessels and containing abnormal intratumoral vessels. To test the effects of potentially anti-angiogenic agents on tumor growth, we then used STC-1 cells stably transfected with the endostatin-coding sequence. Intrahepatic tumor volume showed no significant change at days 4 and 8, but a dramatic decrease at day 28 (9.7 +/- 1.7% of liver tissue versus 25.2 +/- 2.4% in controls), because of a markedly lower number of large nodules (11 +/- 1.8% versus 42 +/- 5.8%) likely to result from an increased apoptotic index (39.4 +/- 5.6% versus 18.3 +/- 3.4). Our results suggest that active angiogenesis is not necessary for the engraftment and early growth of endocrine cells metastatic to the liver but is required at a later stage of progression.

Pancreatic endocrine tumors

Incidental, nonfunctional pancreatic endocrine tumors (PET) are observed with increasing frequency. Most are insulinomas. Endoscopic ultrasound with fine-needle aspiration plays a significant role in the localization and tissue diagnosis of PET. Establishing PET behavior as aggressive or indolent remains challenging especially preoperatively. Newer techniques including DNA and micro-RNA analysis may play a role in this arena. Small benign PET may be enucleated or removed laparoscopically. Surgery is the mainstay of treating advanced disease including those with metastases and Zollinger-Ellison syndrome. The management of multiple endocrine neoplasia type 1 continues to be a challenge, including treating symptoms, targeted resections, and close observation. Diagnosis, management, and prognostication of PET are under evolution and a number of changes in these fronts are anticipated.