Preliminary results of a Japanese nationwide survey of neuroendocrine gastrointestinal tumors

Adrenocorticotropic Hormone-Producing Pancreatic Neuroendocrine Neoplasms: A Systematic Review

OBJECTIVE

Adrenocorticotropic hormone-producing pancreatic neuroendocrine neoplasm (ACTHoma) is an exceedingly rare type of pancreatic neuroendocrine neoplasm (pNEN) that often causes ectopic adrenocorticotropic hormone syndrome. These neoplasms have been found to be very aggressive and challenging to treat. The current systematic review aimed to analyze the clinical features, immunohistochemical characteristics, diagnosis, therapy, and prognosis of ACTHoma.

METHODS

A systematic review of the English- and Chinese-language literature was performed. PubMed, EMBASE, and Wanfang databases were searched to identify articles about ACTHoma in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines.

RESULTS

A total of 210 studies encompassing 336 patients diagnosed with ACTHoma were selected for the systematic review, including 16 Chinese patients.

CONCLUSION

ACTHoma was more common in women (66.4%), and the mean age was 44.7 years. Tumors were generally large, and the mean tumor size was 4.43 cm. The incidence of clinical manifestations was: hypokalemia, 69.3%; diabetes, 63.2%; weakness, 60.1%, hypertension, 56.4%; moon face 41.1%; and edema, 37.4%. These tumors are more commonly found in the tail of pancreas, and the most frequent site of metastasis was the liver. The pNENs or other functioning pNENs could evolve into ACTHoma. ACTHoma is a very rare disease, and the mean follow-up time was 28.3 months.

Cystic Pancreatic Neuroendocrine Tumor in a Patient with Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF-1) is strongly associated with neurofibromas and malignancies. Solid pancreatic neuroendocrine tumors (PanNETs) have been recently reported in patients with NF-1. PanNETs are always solid and rarely present with a cystic appearance due to central necrosis and hemorrhage caused by rapid growth. A 33-year-old female diagnosed with NF-1 at age 16 was referred for evaluation of a pelvic mass found on abdominal ultrasound. Magnetic resonance imaging showed a 6 cm solid pelvic mass adjacent to the left external iliac artery, and contrast-enhanced computed tomography scan showed a 3-cm solid para-aortic mass and a 3-cm cystic mass in the pancreatic tail. Endoscopic ultrasonography showed a cystic tumor with necrotic tissue and septa. Preoperative diagnosis was pancreatic cystic malignancy with para-aortic lymph node metastasis accompanied with a pelvic neurofibroma. These lesions were resected simultaneously. The specimen resected from the pancreas showed a necrotizing cystic tumor invading abutting lymph nodes. Immunohistochemical analysis showed positive chromogranin A and synaptophysin. The Ki-67 index was <1%, and the mitotic count was 1/10 in high power field. Therefore, a non-functional PanNET (grade G1) was diagnosed. The pelvic and para-aortic tumors were both neurofibromas. A cystic appearance is atypical for PanNET and makes preoperative diagnosis difficult. To the best of our knowledge, this is the first report of a cystic PanNET in a patient with NF-1.

Survival comparison between primary hepatic neuroendocrine neoplasms and primary pancreatic neuroendocrine neoplasms and the analysis on prognosis-related factors

BACKGROUND

Primary hepatic neuroendocrine neoplasms (PHNENs) are extremely rare and few articles have compared the prognosis of PHNENs with other neuroendocrine neoplasms (NENs). This study aimed to investigate the different prognosis between PHNENs and pancreatic NEN (PanNENs) and evaluate the relevant prognosis-related factors.

METHODS

From January 2012 to October 2016, a total of 44 NENs patients were enrolled and divided into two groups according to the primary tumor location which were named group PHNENs (liver; n = 12) and group PanNENs (pancreas; n = 32). Demographic, clinical characteristics and survival data were compared between the two groups with Kaplan-Meier method and log-rank tests. Prognostic factors were analyzed using the Cox regression model.

RESULTS

The overall survival of group PHNENs and group PanNENs were 25.4 ± 6.7 months and 39.8 ± 3.7 months, respectively (P = 0.037). The cumulative survival of group PanNENs was significantly higher than that of group PHNENs (P = 0.029). Univariate analysis revealed that sex, albumin, total bilirubin, total bile acid, aspartate aminotransferase, alkaline phosphatase, α-fetoprotein and carbohydrate antigen 19-9, histological types, treatments and primary tumor site were the prognostic factors. Further multivariate analysis indicated that albumin (P = 0.008), histological types NEC (P = 0.035) and treatments (P = 0.005) were the independent prognostic factors. Based on the histological types, the cumulative survival of patients with well-differentiated neuroendocrine tumor was significant higher than that of patients with poorly differentiated neuroendocrine carcinoma in group PHNENs (P = 0.022), but not in group PanNENs (P > 0.05). According to the different treatments, patients who received surgery had significantly higher cumulative survival than those with conservative treatment in both groups (P < 0.05).

CONCLUSIONS

PHNENs have lower survival compared to PanNENs. Histological types and treatments affect the prognosis. Surgical resection still remains the first line of treatment for resectable lesions and can significantly improve the survival.

Clinical characteristics of early neuroendocrine carcinoma in stomach: A case report and review of literature

INTRODUCTION

Gastric neuroendocrine carcinoma (NEC) is rare. It is considered to be aggressive and has a poor prognosis since the diagnosis is usually made at its advanced stage. However, the survival rate is increased in some early gastric NECs. This study showed a case and reviewed the clinical characteristics of early NECs in stomach.

PATIENT CONCERNS

A 38-year-old man displayed no symptoms and underwent the gastric endoscopy test for his health examination, which showed a red slightly depressed lesion 1.0 cm in size on the lesser curvature of gastric cardia. Magnifying endoscopy with narrow-band imaging (NBI) revealed a clear demarcation and an irregular mesh in vessels within the depressed area. The background mucosa was negative for atrophic gastritis and Helicobacter Pylori infection. A contrast-enhanced computed tomography (CT) scan disclosed no obvious thickening of stomach and lymphadenopathy. Blood tests and physical examination were unremarkable. He had not received any surgical treatment and denied a family history of cancer and any genetic disorders. The pathologic result of biopsy from the lesion was suspicious of superficial carcinoma. Then endoscopic submucosal dissection (ESD) was performed.

DIAGNOSIS

Gastric NEC G3 in the early stage (T1aN0M0).

INTERVENTIONS

Concerning this patient's situation, we considered the ESD as a curable treatment. And no radical surgery or adjuvant chemotherapy was arranged.

OUTCOMES

The patient is doing well and displays no recurrence for 11 months, who is still in follow-up.

LESSONS SUBSECTIONS AS PER STYLE

The early diagnosis and effective treatment by endoscopy would contribute to improve the prognosis of gastric NECs.

A case of hyperinsulinemic hypoglycemia related with a calcimimetic agent

We herein report a case of a 60-year-old female receiving hemodialysis who developed severe hyperinsulinemic hypoglycemia and lost her consciousness. A calcimimetic agent had been administered for the secondary hyperparathyroidism. The calcimimetic agent, mimicking the elevation of the extracellular calcium ion concentration, activates calcium-sensing receptors (CaSR) of the parathyroid cells and inhibits the parathyroid hormone secretions. The previous study suggested that the CaSR are also expressed in both human β cells and insulinoma cells, but the reactivity to change in the extracellular calcium ion concentration is different between normal β cells and insulinoma cells. After cessation of the calcimimetic agent, hypoglycemic symptoms disappeared and endogenous insulin secretion dropped to normal levels. However, the result of a prolonged fasting test indicated that she remained hyperinsulinemic even after its cessation, suggesting that she had insulinoma which could not be detected by the imaging examinations. The previous autopsy data showed that there were many cases of the insulinoma without the symptoms of hypoglycemia. We considered the possibility that she had the insulinoma and the pancreatic tumor was too small to promote the insulin secretion and cause hypoglycemia without activation by the calcimimetic agent. We should know that the calcimimetic agent could cause hyperinsulinemic hypoglycemia with the unidentified insulinoma.

Clinicopathological Characteristics of the primary and metastatic Hepatic Neuroendocrine Tumors and the relevant Prognosis-Related Factors: A Retrospective Study of 81 Cases in a Single Chinese Center

Aims: We aim to describe the clinicopathological characteristics of hepatic neuroendocrine tumors (HNETs) and evaluate the relevant prognosis-related factors. Methods: The clinical data of 81 consecutive patients with primary or metastatic HNETs from March 2000 to July 2014 were retrospectively analyzed. Results: The mean (SD) age was 59.68 (11.64) years, 69.15% were men. The percentages of Grade G1, G2 and G3 tumors were 4.94%, 25.93% and 69.13%, respectively. Thirty-five cases were primary HNETs. Primary HNETs were more common in patients with larger tumors, lymph nodes invasions, tumor necrosis and portal vein tumor thrombus. The 1-, 3-, and 5-year overall survival rate were 88.89%, 32.10%, and 8.64%, separately. The relapse rate was 81.48% (66/81) and the mean (SD) relapse time was 18.79 (10.99) months. Reduced survival rate was associated with lymph node metastases (P=0.034), tumor necrosis (P=0.048), hard texture of tumor character (P=0.001), multifocality of tumor numbers (P=0.043), and the immunohistochemical expression of NSE (P=0.000) and Syn (P=0.037). Patients with metastatic HNETs were demonstrated with a more decreased period of Progression-free Survival (PFS) and Overall survival (OS) than their primary HNETs counterparts (P<0.05). Conclusion: Primary HNETs cohort patients were more common with aggressive clinical presentation. The hard texture of tumor character, multifocality of tumor numbers, and the immunohistochemical expression of NSE and Syn were independent predictive factors. Patients who were pathologically diagnosed as the primary HNETs seemed to achieve a long-term survival.

Early Gastroenteropancreatic Neuroendocrine Tumors: Endoscopic Therapy and Surveillance

Neuroendocrine neoplasias (NEN) of the stomach, duodenum, pancreas, appendix, or rectum that are ≤1 cm in size as well as well-differentiated with World Health Organization grade 1 (G1) can be considered 'early' neuroendocrine tumors; they have a very good prognosis. Regarding prognosis, neuroendocrine tumors (NET) G1 must be distinguished from well-differentiated NET G2 and poorly differentiated neuroendocrine carcinomas (NEC) G3. NET are increasing, with a rise in the age-adjusted incidence in the USA by about 700% in the last 40 years. Earlier diagnosis of NET is one of the main epidemiological changes of clinically detected NEN. The general availability of high-resolution endoscopy and advanced radiological imaging techniques has contributed to a shift in the discovery to smaller-sized (≤10 mm) gastrointestinal and pancreatic NET and earlier tumor stages at diagnosis. Thus, screening colonoscopy is effective in the early diagnosis not only of colorectal adenomas and adenocarcinomas but also of rectal NET. Endoscopic resection is the treatment of choice in NET G1 of the stomach, duodenum (despite gastrinoma), and rectum that are ≤10 mm in size, do not infiltrate the muscularis propria (T1), and do not show angioinvasion (V0, L0). Similarly, histologically proven, early pancreatic NET G1 (≤10 mm) may be managed conservatively by regular surveillance. In contrast, small (≤1 cm) NET G1 of the jejunum or ileum are not 'early' tumors and have to be resected surgically with lymph node dissection.

A Systematic Review of Proinsulin-Secreting Pancreatic Neuroendocrine Tumors

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) are a heterogeneous group of islet cell-derived neoplasms with a propensity toward hormone production. Among PNETs, proinsulin-secreting tumors (proinsulinomas) are exceedingly rare. The objective of this study is to collect and summarize the existing literature to provide a comprehensive evaluation of this uncommon disease.

METHODS

A systematic review was performed to characterize the clinicopathologic features of proinsulinoma. Using the electronic biomedical databases PubMed, Ovid Medline, and Embase, 316 publications were screened for relevance of which 14 were selected. We also present two patients with proinsulinoma treated at Yale New Haven Hospital.

RESULTS

Of the 16 patients included in the study, the mean age was 56.8 and there was a 2:1 female predominance. The majority of patients presented with symptomatic hypoglycemia with normal or low insulin levels. Median tumor diameter was 1.2 cm and 80% were located in the body and tail of the pancreas. Following resection, most patients had normalization of hormonal levels without recurrence (75%; 12/16).

CONCLUSION

Proinsulinomas are rare pancreatic neuroendocrine tumors that have the potential to cause hypoglycemia. While insulinomas and proinsulin-secreting tumors have many physiologic parallels, these cases illustrate several key distinctions in their diagnosis and management.

Evaluation of treatment for rectal neuroendocrine tumors sized under 20 mm in comparison with the WHO 2010 guidelines

Rectal neuroendocrine tumor (NET) is a relatively rare lesion of the gastrointestinal tract, but the prospective examination with colonofiberoscopy or endoscopic ultrasound has increased the frequency of its detection. It is often difficult to determine the optimal treatment for NETs sized <20 mm in the clinical setting. Other clinicopathological variables are not considered in the current guidelines and staging systems. Although the effects of lymphovascular invasion are not covered by the World Health Organization (WHO) 2010 guidelines or tumor-node-metastasis (TNM) staging system, this may be promising for the establishment of improved guidelines and staging systems, particularly for early-stage colorectal carcinoids. The aim of the present study was to evaluate rectal NETs sized <20 mm in comparison with the WHO 2010 guidelines. Between January 2005 and December 2013, 40 consecutive patients [26 men and 14 women; median age, 59.3 years (range, 34-81 years)] who underwent endoscopic resection of rectal NETs, and 12 patients undergoing surgical resection of rectal NETs, were enrolled in this retrospective study. The median tumor size was 7.4 mm (range, 3-15 mm). The locations of the NET were the rectosigmoid colon (n=3), the upper rectum (n=13), and the lower rectum (n=25). The NETs were classified by size as 0-5 (n=7), 6-10 (n=29) and 11-15 mm (n=4). The surgical procedures performed included low anterior resection plus esophagectomy (n=1), laparoscopic low anterior resection (n=7) and laparoscopic intersphincteric resection (n=4). Only 1 patient had lymph node metastasis (tumor sized 6-10 mm, with lymphovascular invasion). NET recurrence was not detected in any of the patients. According to the WHO guidelines, the tumors were classified as grade (G)1 (n=8), G2 (n=3) and G1/G2 (n=1). The tumor in the patient with lymph node metastasis was G1. NETs sized <10 mm may be curatively treated by endoscopic resection. However, NETs with either lymphovascular invasion or sized >1 cm carry a risk for metastasis equivalent to that of adenocarcinomas. Therefore, it is mandatory to histologically examine lymphovascular invasion in specimens retrieved via endoscopic resection to determine the necessity for further radical surgery with regional lymph node dissection. The treatment of NETs sized <20 mm as presently defined in the WHO 2010 guidelines requires further evaluation.

Pancreatic Neuroendocrine Tumors and EMT Behavior Are Driven by the CSC Marker DCLK1

Doublecortin-like kinase 1 (DCLK1), a marker for intestinal and pancreatic cancer stem cells, is highly expressed in neuroblastomas. This study was conducted to assess DCLK1 expression levels in pancreatic neuroendocrine tumor (PNET) tissues and to explore the roles of this molecule in clinical tissue from multiple PNET patients, cells (BON1, QGP1, and CM) and tumor xenografts. Immunohistochemically, all PNET tissues highly and diffusely expressed DCLK1 as a full-length isoform, identical to that detected in primary liver NETs. A DCLK1-overexpressing PNET cell line (QGP1-DCLK1) exhibited epithelial-mesenchymal transition (EMT)-related gene signatures, and robust upregulation of Slug (SNAI2), N-Cadherin (CDH2), and Vimentin (VIM) was validated by real-time PCR and immunoblotting. QGP1-DCLK1 cells had increased cell migration in a wound-healing assay and formed significantly larger xenograft tumors in nude mice. The factors involved in the formation of the fast-growing tumors included p-FAK (on Tyr925), p-ERK1/2, p-AKT, Paxillin, and Cyclin D1, which upon knockdown or pharmacologic inhibition of DCLK1 abolished the expression of these molecules. In conclusion, robust and ubiquitous expression of DCLK1 was first demonstrated here in human PNET tissue specimens and cells. DCLK1 characterized the PNET cell behavior, inducing p-FAK/SLUG-mediated EMT. These findings suggest the possibility of developing novel therapeutic strategies against PNETs by targeting DCLK1.Implications: Evidence here reveals that human PNETs diffusely and robustly express the cancer stem cell marker DCLK1, which drives SLUG-mediated EMT, and suggests that NETs share biological features for druggable targets with other tumors, including neuroblastoma that also highly expresses DCLK1. Mol Cancer Res; 15(6); 744-52. ©2017 AACR.

Advances in the diagnosis and treatment of pancreatic neuroendocrine neoplasms in Japan

Several new developments have occurred in the field of pancreatic neuroendocrine neoplasm (PNEN) recently in Japan. First, the utility of chromogranin A (CgA), useful for the diagnosis and monitoring of the treatment response of neuroendocrine neoplasm (NEN), has been demonstrated in Japan. For PNEN diagnosis and treatment, grading and correct histological diagnosis according to the WHO 2010 classification is important. Regarding the histological diagnosis, the advent of endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) has enabled correct pathological diagnosis and suitable treatment for the affected tissue. Furthermore, EUS-FNA has also facilitates the assessment of the presence or absence of gene mutations. In addition, patients who have a well-differentiated neuroendocrine tumor (NET) showing a Ki-67 index of higher than 20 % according to the WHO 2010 classification, have also been identified, and their responses to treatment were found to be different from those of patients with poorly differentiated neuroendocrine carcinoma (NEC). Therefore, the concept of NET G3 was proposed. Additionally, somatostatin receptor type 2 is expressed in several cases of NET, and somatostatin receptor scintigraphy (¹¹¹In-octreoscan) has also been approved in Japan. This advancement will undoubtedly contribute to the localization diagnosis, the identification of remote metastasis, and assessments of the treatment responses of PNEN. Finally, regarding the treatment strategy for PNEN, the management of liver metastasis is important. The advent of novel molecular-targeted agents has dramatically improved the prognosis of advanced PNEN. Multimodality therapy that accounts for the tumor stage, degree of tumor differentiation, tumor volume, and speed of tumor growth is required.

Efficacy of endoscopic ultrasonography and endoscopic ultrasonography-guided fine-needle aspiration for the diagnosis and grading of pancreatic neuroendocrine tumors

BACKGROUND AND AIM

Pancreatic neuroendocrine tumors (pNETs) are histologically categorized according to the WHO 2010 classification by their mitotic index or Ki-67 index as G1, G2, or G3. The present study examined the efficacy of endoscopic ultrasonography (EUS) and EUS-guided fine-needle aspiration (EUS-FNA) in the diagnosis and grading of pNET.

METHODS

We retrospectively reviewed 61 pNETs in 51 patients who underwent EUS between January 2007 and June 2014. All lesions were pathologically diagnosed by surgical resection or EUS-FNA. We evaluated the detection rates of EUS for pNET and sensitivity of EUS-FNA, and compared the Ki-67 index between EUS-FNA samples and surgical specimens. EUS findings were compared between G1 and G2/G3 tumors.

RESULTS

EUS showed significantly higher sensitivity (96.7%) for identifying pNET than CT (85.2%), MRI (70.2%), and ultrasonography (75.5%). The sensitivity of EUS-FNA for the diagnosis of pNET was 89.2%. The concordance rate of WHO classification between EUS-FNA and surgical specimens was 69.2% (9/13). The concordance rate was relatively high (87.5%, 5/6) in tumors <20 mm but lower (57.1%; 4/7) in tumors ≥20 mm. Regarding EUS findings, G2/G3 tumors were more likely to be large (>20 mm), heterogeneous, and have main pancreatic duct (MPD) obstruction than G1 tumors. Multivariate analysis showed large diameter and MPD obstruction were significantly associated with G2/G3 tumors.

CONCLUSIONS

EUS and EUS-FNA are highly sensitive and accurate diagnostic methods for pNET. Characteristic EUS findings such as large tumor size and MPD obstruction are suggestive of G2/G3 tumors and would be helpful for grading pNETs.

Islet Cell Tumors of the Pancreas

Islet cell tumors of the pancreas, also known as pancreatic neuroendocrine tumors, constitute less than 5% of pancreatic tumors, and 7% of all neuroendocrine tumors. Most are non-functional, and patients often present with metastatic disease. Functional tumors present with distinct clinical syndromes. Accurate staging is critical as surgery is both the cornerstone of treatment, and the only hope for cure. Medical management involves treating the manifestations of hormonal excess, and using somatastatin analogues when appropriate. Systemic chemotherapy, targeted molecular therapy, and peptide receptor radiotherapy may be used for refractory disease in lieu of or as an adjunct to surgery.

Pancreatic neuroendocrine tumors: A single-center 20-year experience with 100 patients

BACKGROUND/OBJECTIVES

Pancreatic neuroendocrine neoplasms (NENs) are rare tumors, exhibiting several morphological, functional, and behavioral characteristics. However, only few reports have evaluated large case series of pancreatic NEN.

METHODS

We conducted a retrospective review of 100 consecutive patients with pancreatic NEN diagnosed pathologically and treated at the National Cancer Center Hospital between 1991 and 2010.

RESULTS

The study included 48 males and 52 females (median age: 55 years). Fourteen patients had clinical symptoms caused by excess hormone secretion at diagnosis. Twelve patients were diagnosed with neuroendocrine tumor (NET) G1, 54 with NET G2, and 32 with neuroendocrine carcinoma (NEC) as per the 2010 World Health Organization classification. Distant metastases were observed in 25%, 43%, and 84% of the patients with NET G1, NET G2, and NEC, respectively. Serum levels of neuron-specific enolase and lactate dehydrogenase significantly increased in patients with NEC compared with those in patients with NET G1/G2. The 5-year survival rates of patients with NET G1, NET G2, and NEC were 91%, 69%, and 10%, respectively. Good performance status (PS), lower stage, and histopathological grade were identified as independent favorable prognostic factors.

CONCLUSIONS

Patients with NET G1/G2 treated with surgical resection had a good prognosis. Most patients with NEC exhibited distant metastases and had a poor prognosis. Staging classification and the WHO 2010 grading are important factors for selecting the appropriate treatment strategy and predicting prognosis for patients with pancreatic NEN.

Gastric neuroendocrine tumors: prevalence in Europe, USA, and Japan, and rationale for treatment with a gastrin/CCK2 receptor antagonist

OBJECTIVE

Gastric carcinoids (neuroendocrine tumors) arise from enterochromaffin-like cells in the gastric mucosa. Most are caused by hypergastrinemia. The objectives were to determine if their prevalence in Europe, USA and Japan meets the criteria for an orphan disease and to justify treatment with a gastrin/CCK2 receptor antagonist.

METHODS

We obtained data from European and USA cancer registries, and searched PubMed.

RESULTS

Prevalence per 10,000 population obtained from cancer registries was: median 0.32 (range 0.09-0.92) for Europe; and 0.17 for the USA, equivalent to 4812 for the whole population. A PubMed search for gastric carcinoids yielded prevalence for Japan only, which was 0.05 per 10,000 population, equivalent to 665 for the entire population. A further search for gastric carcinoids in patients with pernicious anemia (PA) or autoimmune chronic atrophic gastritis (CAG), two presentations of about 80% of gastric carcinoids, produced prevalence rates of 5.2-11%. Prevalence of PA itself was 0.12-1.9%. Data on CAG epidemiology were sparse.

CONCLUSION

Prevalence of gastric carcinoids varied widely. All sources probably underestimate prevalence. However, prevalence was below the limits required for recognition by drug regulatory authorities as an orphan disease: 5 per 10,000 population of Europe; 200,000 for the whole population of the USA; and 50,000 for the whole population of Japan. Because gastric carcinoids are an orphan disease, and nonclinical and healthy volunteer studies support treatment with netazepide, a gastrin/CCK2 antagonist, netazepide has been designated an orphan medicinal product in Europe and the USA for development as targeted treatment for gastric carcinoids.

The up-to-date review of epidemiological pancreatic neuroendocrine tumors in Japan

Pancreatic neuroendocrine tumors (PNETs) were considered an extremely rare disease. However, in recent years, the number of patients with PNET has increased rapidly. According to an epidemiological survey conducted in Japan, the number of treated patients with PNETs in 2010 was approximately 1.2-times that in 2005, and the number of new incidences of non-functional PNETs in 2010 was approximately 1.7-times that in 2005. Among functional PNETs, insulinoma was most prevalent, followed by gastrinoma. To diagnose PNETs, correct histological diagnosis is most important. According to the World Health Organization 2010 classification criteria, neuroendocrine tumors (NETs) are categorized into well-differentiated NETs and poorly differentiated neuroendocrine carcinomas (NECs). NECs accounted for 7.6% of all NETs, and functional and non-functional PNETs accounted for 2.1% and 10.1%, respectively. Patients with distant metastasis accounted for 19.9%, and those with multiple endocrine neoplasia type 1 accounted for 4.3%. When treating PNETs, it is necessary to correctly evaluate the functionality and progression of tumors, the presence or absence of metastasis, and the degrees of differentiation and malignant potential of tumors. A new registration system from the Japan Neuroendocrine Tumor Society will start to be used in 2015, which will help further dissemination of Japanese epidemiological information to the world.

Epidemiological trends of pancreatic and gastrointestinal neuroendocrine tumors in Japan: a nationwide survey analysis

BACKGROUND

Although neuroendocrine tumors (NETs) are rare, the number of patients with NET is increasing. However, in Japan, there have been no epidemiological studies on NET since 2005; thus, the prevalence of NET remains unknown.

METHODS

We reported the epidemiology of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) [pancreatic neuroendocrine tumors (PNETs) and gastrointestinal neuroendocrine tumors (GI-NETs)] in Japan in 2005. Here, we conducted the second nationwide survey on patients with GEP-NETs who received treatment in 2010.

RESULTS

A total of 3,379 patients received treatment for PNETs in 2010, representing a 1.2-fold increase in the number of patients from 2005 to 2010. The prevalence was estimated to be 2.69/100,000, with an annual onset incidence of 1.27/100,000 in 2010. Non-functioning tumor (NF)-PNETs comprised 65.5% of cases followed by insulinoma (20.9%) and gastrinoma (8.2%). Interestingly, the number of patients with NF-PNETs increased ~1.8 fold since 2005. A total of 19.9% of patients exhibited distant metastasis at initial diagnosis; 4.3% had complications with multiple endocrine neoplasia type 1 (MEN-1), and only 4.0% had NF-PNETs associated with MEN-1. Meanwhile, an estimated 8,088 patients received treatment for GI-NETs, representing a ~1.8-fold increase since 2005. The prevalence was estimated to be 6.42/100,000, with an annual onset incidence of 3.51/100,000. The locations of GI-NETs varied: foregut, 26.1%; midgut, 3.6%; and hindgut, 70.3%. Distant metastasis and complications with MEN-1 were observed in 6.0 and 0.42% at initial diagnosis, respectively. The frequency of carcinoid syndrome in patients with GI-NETs was 3.2%.

CONCLUSION

We clarified the epidemiological changes in GEP-NETs from 2005 to 2010 in Japan.

Practical management and treatment of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (NETs) are uncommon disease, about which little is known. Pancreatic NETs are usually slow growing and their malignant potential are often underestimated. The management of this disease poses a challenge because of the heterogeneous clinical presentation and varying degrees of aggressiveness. Recently, several guidelines for the management of pancreatic NETs have been established and help to devise clinical strategy. In the treatment algorithms, however, a lot of uncertain points are included. Practical treatment decisions of pancreatic NETs are still sometimes made in a patient- and/or physicians-oriented manner. The tumor grading system proposed by the European Neuroendocrine Tumor Society (ENETS) gives important prognostic information, however, the implication of grading regarding medical treatment strategies to choose has not yet been clarified. Moreover, the place of surgical treatment is unclear in the overall management course of advanced pancreatic NETs. In some cases, practical management and treatment have to be individualized depending on predominant symptoms, tumor spread, and general health of the patients. Current issues and a few points to make a strategy in the management of pancreatic NETs would be reviewed.

The usefulness of endoscopic ultrasound-guided fine-needle aspiration for the diagnosis of pancreatic neuroendocrine tumors based on the World Health Organization classification

BACKGROUND

We assessed the controversial topic of using 22-gauge needles in endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for the diagnosis and evaluation of Ki67 labeling indices (Ki67LI) of pancreatic neuroendocrine tumors (pNET).

METHODS

Thirty-eight patients with pNET who underwent EUS-FNA between January 1, 2008 and December 31, 2012 were enrolled in this study. When available, the Ki67LI and WHO classifications obtained by EUS-FNA and surgical resection were compared.

RESULTS

EUS-FNA with a 22-gauge needle acquired sufficient histological sample to correctly diagnose pNET in 35 cases (92.1%). Both EUS-FNA and surgical histological specimens were available for 19 cases, and grading classes of the 2 procedures were consistent in 17 cases (89.5%) according to the WHO classification based on the Ki67LI. Tumor size was associated with a difference in the Ki67LI between the 2 procedures, although the Ki67LI was almost completely consistent for tumors less than 18 mm in size.

CONCLUSIONS

EUS-FNA with a 22-gauge needle is a safe and highly accurate technique for the diagnosis of pNET. There was a clear correlation between the Ki67LI of histological specimens acquired by EUS-FNA and surgery. EUS-FNA with a 22-gauge needle is useful to predict the WHO classification of pNET.

Calcified liver metastases from a non-functioning pancreatic neuroendocrine tumor

Neuroendocrine tumors consist of a spectrum of malignancies that arise from neuroendocrine cells throughout the body. Pancreatic neuroendocrine tumors are rare tumors, with an incidence of 3.65 per 100,000 individuals per year, and they account for 1-2 % of all pancreatic neoplasms. A non-functioning pancreatic neuroendocrine tumor with multiple liver metastases with calcifications was diagnosed in a 43-year-old female with diabetes mellitus. Early phase-enhanced computed tomography (CT) showed a hypovascular mass in the pancreatic body and tail with calcifications and multiple liver metastatic masses with calcifications. Percutaneous liver biopsy showed homogenous nuclear chromatins and tumor cells with acidophilic cytoplasm against the hyaline interstitium, and a non-functioning pancreatic neuroendocrine tumor was diagnosed. An interesting clinical image of a metastasis from a pancreatic neuroendocrine tumor is presented in which multiple liver tumors were accompanied by dystrophic calcifications. CT and percutaneous liver biopsy play an important role in the diagnosis of a non-functioning pancreatic neuroendocrine tumor, and are valuable diagnostic methods in planning treatment.

Clinicopathological characteristics and prognosis-related factors of resectable pancreatic neuroendocrine tumors: a retrospective study of 104 cases in a single Chinese center

OBJECTIVE

The purpose was to describe the clinicopathological characteristics of pancreatic neuroendocrine tumors (pNETs) and evaluate prognosis-related factors in potentially resectable pNETs.

METHODS

The clinical data of 104 patients with pNETs who underwent surgery were retrospectively analyzed.

RESULTS

The mean (SD) age was 49.8 (14.6) years. The percentages of TNM stages I, II, III, and IV tumors were 25.0%, 44.2%, 22.1%, and 8.7%, respectively. Twenty-seven cases were functional. Nonfunctional pNETs were more common in patients with large tumors, advanced age, higher mitotic count, neural invasion, extrapancreatic organ invasion, liver metastases, and advanced staging (P < 0.05). The 5-year overall survival rate was 93%. The relapse rate was 28.6% (28/98), and the mean (SD) relapse time was 38.7 (31.7) months. Reduced survival rate was associated with older patients (>60 years) (P = 0.026), patients with a higher Ki-67 index (>2%) (P = 0.024), regional lymph node metastases (P = 0.033), liver metastases (P = 0.015), neural invasion (P = 0.017), necrosis (P = 0.042), and major vascular invasion (P = 0.023). Age of more than 60 years (P = 0.047; hazard ratio [HR], 5.2), major vascular invasion (P = 0.030; HR, 5.8), and a Ki-67 index greater than 2% (P = 0.008; HR, 10.3) were independent predictors.

CONCLUSIONS

Nonfunctional pNETs were more common with aggressive clinical presentation. Age of more than 60 years, major vascular invasion, and a Ki-67 index greater than 2% were independent predictive factors. Patients who underwent a potentially curative resection seemed to achieve long-term survival.

Clinical course of neuroendocrine tumors with different origins (the pancreas, gastrointestinal tract, and lung)

OBJECTIVES

Neuroendocrine tumor originates from several sites. This study was conducted to reveal the differences in clinical course of neuroendocrine tumors by the origin.

METHODS

We reviewed data of patients diagnosed with neuroendocrine tumor between January 1996 and July 2007.

RESULTS

A total of 371 patients were enrolled [pancreas 60, gastrointestinal (GI) tract 210, lung 35, other sites 46, unknown primary sites 20]. The primary tumor site correlated with the stage (P=0.000) and grade (P=0.000). At diagnosis, metastasis was observed in 28.3%, 6.7%, and 2.9% of the cases in pancreatic, GI, and pulmonary neuroendocrine tumors, respectively. Grade 3 neuroendocrine tumor was observed in 7.7%, 0.5%, and 0.0% in pancreatic, GI, and pulmonary neuroendocrine tumors. Overall survival was 116.0 months (95% confidence interval, 86.9-145.1). Overall survival was 116.0 months in pancreatic neuroendocrine tumor, not reached in GI neuroendocrine tumor and 120.0 months in pulmonary neuroendocrine tumor (P=0.024). The recurrence rate was 18.0%. It was 20.9%, 11.9%, and 2.9% in pancreatic, GI, and pulmonary neuroendocrine tumors (P=0.062). In multivariate analysis, stage, grade, and age were prognostic for overall survival (OS). Stage, grade, and sex were prognostic for disease-free survival.

CONCLUSIONS

Neuroendocrine tumors from the pancreas, GI tract, and lung showed different clinical characteristics.

Unusual suspects: pulmonary opportunistic infections masquerading as tumor metastasis in a patient with adrenocorticotropic hormone-producing pancreatic neuroendocrine cancer

Pancreatic neuroendocrine tumors (p-NETs) are a rare group of neoplasms but with increasing incidence. The atypical complications that arise in the setting of functional endocrine tumors are underreported and therefore have not received sufficient attention and the necessary mention in the oncology literature. The clinical implications of these complications pose management challenges starting with the difficulty in establishing diagnosis, accurate staging and optimal treatment of the primary process. We present the case of a middle-aged woman diagnosed with adrenocorticotropic hormone-producing carcinoma arising from the pancreas whose case was complicated by excessive uncontrolled hypercortisolism and reactivation of pulmonary opportunistic infections that confounded her management. We believe that this case illustration will be of value to practicing oncologists and other groups of physicians who are called upon to participate in the multidisciplinary treatment of these relatively rare but highly challenging cases.

Relationship between clinical characteristics and survival of gastroenteropancreatic neuroendocrine neoplasms: A single-institution analysis (1995-2012) in South China

BACKGROUND

Gastroenteropancreatic neuroendocrine neoplasm (GEP-NEN) is the most common type of neuroendocrine tumors accounting for 65-75% of neuroendocrine neoplasms (NENs). Given the fact that there are few studies on GEP-NENs among Chinese patients, we performed a retrospective study in South China.

METHODS

Totally 178 patients with GEP-NENs treated at the First Affiliated Hospital of Sun Yat-sen University between January 1995 and May 2012 were analyzed retrospectively.

RESULTS

Pancreas was found the most common site of involvement (34.8%). 149 patients (83.7%) presented as non-functional tumors with non-specific symptoms such as abdominal pain (33.7%); carcinoid syndrome was not found in this study. Several methods are useful for localization of GEP-NENs, yielding varied detection rates from 77.8% to 98.7%. Positive rates of chromogranin A (CgA) and synaptophysin (Syn) immunhistochemically were 69.1% and 90.2%, respectively. 87 patients (51.5%) had G1 tumors, 31(18.3%) G2 tumors and 51 (30.2%) G3 tumors. Neuroendocrine tumor (NET), neuroendocrine carcinoma (NEC) and mixed adenoendocrine carcinoma (MANEC) were 69.8%, 27.2% and 3.0%, respectively. 28.1% of patients presented with distant disease. Surgery was performed in 152 (85.4%) patients, and overall 5-year survival rate was 54.5%. Functionality, G1 grading and NET classification were associated with favorable prognosis in univariate analysis. Distant metastasis contributed to unfavorable prognosis of these tumors.

CONCLUSIONS

Nonfunctional tumors with non-specific symptoms account for the majority of GEP-NENs. Diagnosis depends on pathological classification. Multidisciplinary treatments could help improve the outcome.

Relationship between clinical characteristics and survival of gastroenteropancreatic neuroendocrine neoplasms: A single-institution analysis (1995-2012) in South China

BACKGROUND

Gastroenteropancreatic neuroendocrine neoplasm (GEP-NEN) is the most common type of neuroendocrine tumors accounting for 65-75% of neuroendocrine neoplasms (NENs). Given the fact that there are few studies on GEP-NENs among Chinese patients, we performed a retrospective study in South China.

METHODS

Totally 178 patients with GEP-NENs treated at the First Affiliated Hospital of Sun Yat-sen University between January 1995 and May 2012 were analyzed retrospectively.

RESULTS

Pancreas was found the most common site of involvement (34.8%). 149 patients (83.7%) presented as non-functional tumors with non-specific symptoms such as abdominal pain (33.7%); carcinoid syndrome was not found in this study. Several methods are useful for localization of GEP-NENs, yielding varied detection rates from 77.8% to 98.7%. Positive rates of chromogranin A (CgA) and synaptophysin (Syn) immunhistochemically were 69.1% and 90.2%, respectively. 87 patients (51.5%) had G1 tumors, 31(18.3%) G2 tumors and 51 (30.2%) G3 tumors. Neuroendocrine tumor (NET), neuroendocrine carcinoma (NEC) and mixed adenoendocrine carcinoma (MANEC) were 69.8%, 27.2% and 3.0%, respectively. 28.1% of patients presented with distant disease. Surgery was performed in 152 (85.4%) patients, and overall 5-year survival rate was 54.5%. Functionality, G1 grading and NET classification were associated with favorable prognosis in univariate analysis. Distant metastasis contributed to unfavorable prognosis of these tumors.

CONCLUSIONS

Nonfunctional tumors with non-specific symptoms account for the majority of GEP-NENs. Diagnosis depends on pathological classification. Multidisciplinary treatments could help improve the outcome.

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.

An unusual case of subclinical diffuse glucagonoma coexisting with two nodules in the pancreas: characteristic features on computed tomography

A lesion was discovered in the tail of the pancreas by ultrasonography performed during a health checkup for a 59-year-old Japanese man. Abdominal contrast-enhanced computed tomography (CE-CT) revealed strong enhancement in a 4-cm tumor in the pancreatic tail and in a 1-cm tumor in the pancreatic body. Serum glucagon levels were elevated to 54,405 pg/mL and a preoperative diagnosis of glucagonoma was made. The pancreatic tail and spleen were resected en bloc, along with a protruding tumor in the pancreatic body. However, histopathological evaluation revealed diffuse glucagonoma throughout the pancreas. When we retrospectively reviewed abdominal CE-CT after the operation, the entire pancreas was seen to be enlarged and diffusely enhanced by strong spots. Immunohistochemical examination using anti-CD31 demonstrated rich microvessels in two solid glucagonomas as well as microglucagonoma throughout the entire pancreas, indicating hypervascularity. Enlarged pancreas and diffuse enhancement of the pancreas by strong spots may be characteristic features of diffuse glucagonoma on abdominal CE-CT.

Neuroendocrine liver metastases: Contributions of endoscopy and surgery to primary tumor search

Neuroendocrine tumors (NETs) are diagnosed with increasing frequency and patients often present with liver metastases at the time of diagnosis. Apart from treatment of the metastases, resection of the primary tumor at an early phase is recommended to prevent complications, although it may be difficult to locate, especially in patients with functionally inactive NETs. Small and multifocal tumors in the jejunum and ileum represent a particular challenge. Primary hepatic neuroendocrine carcinoma is extremely rare and is diagnosed only after exclusion of other primary tumors. Therefore, some uncertainty may remain, as small non-hepatic primary tumors may escape detection. Diagnostic work-up in these patients includes biochemical assays and imaging modalities (also comprising specific techniques of scintigraphy and positron emission tomography). This editorial highlights the contributions of endoscopy and operative exploration to the search for the primary tumor. Besides esophago-gastro-duodenoscopy, endoscopic ultrasonography, colonoscopy and bronchoscopy, special endoscopic techniques such as balloon enteroscopy or capsule endoscopy are used with growing experience. Compared with balloon enteroscopy, capsule endoscopy is non-invasive and better tolerated, but it cannot localize a lesion precisely and does not allow biopsy or removal of lesions. Before proceeding to surgery, a discussion of the findings by a tumor board should be a standard procedure. Improvements in diagnostic tools have created new perspectives for the detection of obscure primary tumors in patients with neuroendocrine liver metastases, and these searches are best coordinated by a multidisciplinary team.

Contemporary management of nonfunctioning pancreatic neuroendocrine tumors

BACKGROUND

This article reviews the current literature and recommendations pertaining to the management of nonfunctioning pancreatic neuroendocrine tumors.

DISCUSSION

In recent years the detection of nonfunctioning pancreatic neuroendocrine tumors has increased coincident with the increased use of cross-sectional imaging and is now thought to represent 2-10% of all pancreatic tumors. Improved understanding of the biology and behavior of these heterogeneous tumors is needed to guide therapy. The present review discusses diagnostics, therapeutics including emerging molecular analytics, and surveillance recommendations.

[Neuroendocrine tumors of the duodenum and pancreas. Surgical strategy]

The incidence of neuroendocrine tumors (NET) has increased worldwide by 3-5 times over the last decades. This is mainly based on the broad use of imaging modalities such as computed tomography (CT) and endoscopic approaches. As a consequence many duodenal and pancreatic tumors are detected in an early stage resulting in an improved prognosis of these patients. Besides the measurement of serum chromogranin A and 5-hydroxy indolic acid measured in 24 h urine collection, CT, endosonographic ultrasound (EUS) and endoscopy are important diagnostic tools. About 20% of all patients with pancreatic and duodenal NETs are diagnosed because of specific symptoms. More than 95% of diagnosed NETs are sporadic tumors. Whenever possible these patients should be treated by resection. Benign neuroendocrine duodenal tumors up to 1 cm in size can be removed endoscopically. The endoscopic resection of larger tumors should be performed surgically. The therapy of hereditary NETs of the duodenum and the pancreas should be decided after interdisciplinary discussion. However, even these patients seem to benefit from resection. In case of metastatic disease debulking surgery should be considered if more than 90% of the tumor mass can be resected. In patients with extensive liver metastases but resectable primary NET, liver transplantation is a reasonable option. There is no consensus about adjuvant or neoadjuvant treatment of duodenal or pancreatic NETs. The therapy with everolimus or sunitinib in advanced tumor stages has shown promising results. The administration of somatostatin analogues or antacids is appropriate for symptom reduction.

A renaissance in therapeutic options for pancreatic neuroendocrine tumors

The field of pancreatic neuroendocrine tumors (NETs) has seen a remarkable renaissance in recent years with exponential increases in published research, clinical trials, and U.S. Food and Drug Administration (FDA)-approved treatments. Surgical resection remains the foundation for management of locoregional disease. However, for patients with advanced disease, novel therapeutic options have emerged. Two separate randomized placebo-controlled studies have shown prolonged progression-free survival (PFS) with everolimus or sunitinib. Future studies are designed to answer questions about the role of somatostatin analogs as antiproliferative agents, combinations of biologic therapies, and new cytotoxic chemotherapy backbones.

Management of early gastrointestinal neuroendocrine neoplasms

Neuroendocrine neoplasms (NENs) of the stomach, duodenum, appendix or rectum that are small (≤ 1 cm) and well differentiated can be considered “early” tumors, since they generally have a (very) good prognosis. In the new WHO classification of 2010, these neoplasms are called neuroendocrine tumors/ carcinoids (NETs), grade (G) 1 or 2, and distinguished from poorly differentiated neuroendocrine carcinomas (NECs), G3. NETs are increasing, with a rise in the age-adjusted incidence in the U.S.A. by about 700 % in the last 35 years. Improved early detection seems to be the main reason for these epidemiological changes. Both the better general availability of endoscopy, and imaging techniques, have led to a shift in the discovery of smaller-sized (≤ 10-20 mm) intestinal NETs/carcinoids and earlier tumor stages at diagnosis. Endoscopic screening is therefore effective in the early diagnosis, not only of colorectal adenocarcinomas, but also of NETs/carcinoids. Endoscopic removal, followed up with endoscopic surveillance is the treatment of choice in NETs/carcinoids of the stomach, duodenum and rectum that are ≤ 10 mm in size, have a low proliferative activity (G1), do not infiltrate the muscular layer and show no angioinvasion. In all the other intestinal NENs, optimal treatment generally needs surgery and/or medical therapy depending on type, biology and stage of the tumor, as well as the individual situation of the patient.

[Complete and sustained remission of liver metastases from neuroendocrine tumor with somatostatin analogue therapy]

Somatostatin analogues represent a major treatment modality in the therapy of neuroendocrine tumors. Their efficacy is well documented in the inhibition of hormone secretion; however, novel data seem to underline their effectiveness in tumor regression, as well. In this report authors present a case of type 1 neuroendocrine tumors of the stomach associated with liver metastases. Somatostatin analogue treatment resulted in a complete regression of the primary tumor and the metastases within two years. This case draws attention on the importance of somatostatin analogue treatment not only in the control of hormonal symptoms but also in the inhibition of tumor growth.

A case of a giant glucagonoma with parathyroid hormone-related peptide secretion showing an inconsistent postsurgical endocrine status

A 53-year-old woman was admitted because of a giant pancreatic tumor. Hypercalcemia and a high serum parathyroid hormone-related peptide (PTHrP) level were observed. A hypoglycemic attack occurred during pancreatectomy, and the surgical specimen revealed a PTHrP-secreting glucagonoma. Liver metastases developed 1 and 5.5 years later, and bone metastases appeared 6 years after surgery. Her serum PTHrP concentrations remained normal after surgery, despite re-elevation of the serum glucagon concentration after recurrence. The clinical course of this case illustrates the process of development of neuroendocrine tumors secreting two or more hormones.

Neuroendocrine tumors of the small bowels are on the rise: Early aspects and management

Neuroendocrine tumors of the small bowel are on the rise. In the US they have increased by 300%-500% in the last 35 years. At the same time their prognosis is much improved. Today, most neuroendocrine tumors (NETs) of the duodenum are detected "incidentally" and therefore recognized at an early stage. Duodenal NETs which are well differentiated, not larger than 10 mm and limited to the mucosa/submucosa can be endoscopically resected. The management of duodenal NETs ranging between 10 and 20 mm needs an interdisciplinary discussion. Endoscopic ultrasound is the method of choice to determine tumor size and depth of infiltration. Surgery is recommended for well-differentiated duodenal NET tumors greater than 20 mm, for localized sporadic gastrinomas (of any size) and for localized poorly differentiated NE cancers. Surgery is recommended for any ileal NET. Advanced ileal NETs with a carcinoid syndrome are treated with long-acting somatostatin analogs. This treatment significantly improves (progression-free) survival in patients with metastatic NETs of the ileum. For optimal NET management, tumor biology, type, localization and stage of the neoplasm, as well as the patient's individual circumstances have to be taken into account.

Recent standardization of treatment strategy for pancreatic neuroendocrine tumors

Recent advances in localization techniques, such as the selective arterial secretagogue injection test (SASI test) and somatostatin receptor scintigraphy have promoted curative resection surgery for patients with pancreatic neuroendocrine tumors (PNET). For patients with sporadic functioning PNET, curative resection surgery has been established by localization with the SASI test using secretin or calcium. For curative resection of functioning PNET associated with multiple endocrine neoplasia type 1 (MEN 1) which are usually multiple and sometimes numerous, resection surgery of the pancreas and/or the duodenum has to be performed based on localization by the SASI test. As resection surgery of PNET has increased, several important pathological features of PNET have been revealed. For example, in patients with Zollinger-Ellison syndrome (ZES), duodenal gastrinoma has been detected more frequently than pancreatic gastrinoma, and in patients with MEN 1 and ZES, gastrinomas have been located mostly in the duodenum, and pancreatic gastrinoma has been found to co-exist in 13% of patients. Nonfunctioning PNET in patients with MEN 1 becomes metastatic to the liver when it is more than 1 cm in diameter and should be resected after careful observation. The most important prognostic factor in patients with PNET is the development of hepatic metastases. The treatment strategy for hepatic metastases of PNET has not been established and aggressive resection with chemotherapy and trans-arterial chemoembolization have been performed with significant benefit. The usefulness of octreotide treatment and other molecular targeting agents are currently being assessed.

[Neuroendocrine tumors of the stomach. Risk stratification and therapy]

The diagnosis and therapy of neuroendocrine tumors (NETs) of the stomach are based on their exact classification and risk stratification. Since the incidence of gastric NETs has risen sharply over the last 35 years and most tumors are detected endoscopically at an early stage, they have come to represent a challenge for the pathologist. Gastric NETs are classified according to the WHO and TNM classifications and additionally separated into four biologically distinct types: Well differentiated type 1 and 2 gastric NETs (G1) smaller than 2 cm, and type 3 smaller than 1 cm that do not infiltrate the muscularis propria or show angioinvasion have a good prognosis and can be removed endoscopically. Well differentiated type 1 and 2 gastric NETs (G1-G2) larger than 2 cm or type 3 with a diameter above 1 cm or with infiltration of the muscular wall and/or angioinvasion and poorly differentiated (type 4) neuroendocrine carcinomas carry a poor prognosis and need to be treated aggressively. Endosonography is the method of choice for determining the size, depth of infiltration and presence of lymph node metastases. With exact diagnosis and adequate treatment, the majority of patients with gastric NETs have a favorable prognosis.

DNA methyltransferases 1, 3a, and 3b overexpression and clinical significance in gastroenteropancreatic neuroendocrine tumors

The alteration of DNA methylation is one of the most common epigenetic changes in human cancers. Three genes, namely, DNA methyltransferase 1, 3a, and 3b, which code for DNA methyltransferases that affect promoter methylation status, are thought to play an important role in the development of cancers and may be good anticancer therapy targets. The methylation of tumor suppressor genes has been reported in gastroenteropancreatic neuroendocrine tumors; however, there have been no studies about DNA methyltransferase protein expression and its clinical significance in gastroenteropancreatic neuroendocrine tumors. In this study, the expression of DNA methyltransferase 1, 3a, and 3b was studied in 63 gastroenteropancreatic neuroendocrine tumors by immunohistochemistry. The expression of DNA methyltransferase 1, 3a, and 3b was frequently detected in gastroenteropancreatic neuroendocrine tumors (87%, 81%, and 75%, respectively). The DNA methyltransferase 3a expression level was significantly higher in poorly differentiated neuroendocrine carcinomas than in well-differentiated neuroendocrine tumors or well-differentiated neuroendocrine carcinomas (P < .01 and P < .05, respectively). The expression of DNA methyltransferase 1, 3a, and 3b showed significantly higher levels in stage IV tumors than in stage I or II tumors. In addition, the expression levels of DNA methyltransferase 1, 3a, and 3b were positively correlated with the MIB-1 labeling index in gastroenteropancreatic neuroendocrine tumors (R = 0.293, P = .019; R = 0.457, P = .001; and R = 0.249, P = .049; respectively). In addition, the expression levels and positive immunostaining frequencies of DNA methyltransferase 3a and 3b were significantly lower in midgut neuroendocrine tumors than in foregut or hindgut neuroendocrine tumors. Our findings suggest that the overexpression of DNA methyltransferase 1, 3a, and 3b is related to tumorigenesis and the progression of gastroenteropancreatic neuroendocrine tumors.

Epidemiological study of gastroenteropancreatic neuroendocrine tumors in Japan

BACKGROUND

There have been few epidemiological studies on gastroenteropancreatic neuroendocrine tumors (GEP-NETs) in Japan.

METHODS

We examined the epidemiology of GEP-NETs [pancreatic endocrine tumors (PETs) and gastrointestinal neuroendocrine tumors (GI-NETs)] in Japan in 2005 using a nationwide stratified random sampling method.

RESULTS

A total of 2,845 individuals received treatment for PETs. Prevalence was estimated as 2.23/100,000 with an annual onset incidence of 1.01/100,000. Non-functioning tumor (NF)-PET constituted 47.4%, followed by insulinoma (38.2%) and gastrinoma (7.9%). Distant metastases were reported in 21% patients with NF-PETs and occurred more frequently as tumor size increased (>2 cm). Multiple endocrine neoplasia type 1 (MEN-1) was detected in 10% of PETs but only in 6.1% of NF-PETs. NF-PETs were detected incidentally by physical examination in 24% patients. In 2005, an estimated 4,406 patients received treatment for GI-NETs. Prevalence was estimated as 3.45/100,000, with an annual onset incidence of 2.10/100,000. The locations of GI-NETs varied: foregut, 30.4%; midgut, 9.6%; and hindgut, 60.0%. Distant metastases were observed in 6%. Lymph node metastases occurred more frequently as tumor size increased (>1 cm). The frequency of MEN-1 complications was 1%. Physical examination revealed GI-NETs in 44% patients. The frequency of symptomatic GI-NETs was 3.4%. Interestingly, 77.1% of patients with foregut GI-NETs had type A gastritis.

CONCLUSION

Our results show there are large differences in GEP-NETs between Japan and Western nations, primarily due to differences in the presence of MEN-1 in NF-PETs and the location, symptomatic status, and prevalence of malignancy in GI-NETs.

A case of ectopic adrenocorticotropic hormone-producing pancreatic neuroendocrine tumor with multiple liver metastases

Ectopic adrenocorticotropic hormone (ACTH) production by the pancreatic neuroendocrine tumor (p-NET) is relatively rare, and patients with this tumor show poor prognosis. In this study, we present the case of a 64-year-old woman who presented with ectopic ACTH syndrome due to p-NET with multiple liver metastases. Computed tomography revealed that she had multiple masses in the liver and a solid mass in the head of the pancreas. Endocrinological examinations revealed markedly elevated plasma ACTH (735.0 pg/mL) and cortisol (34.7 microg/dL) levels associated with hypokalemia (2.7 mEq/L), diabetes and typical Cushingoid features. Histological examinations by needle biopsy of liver tumors in S5 and S8 indicated metastatic ACTH-producing NET, which was also confirmed by venous sampling. The metastatic live tumor was somatostatin receptor (SSTR)-2a- and SSTR-5-positive as revealed by immunohistochemical staining, and reverse transcription polymerase chain reaction revealed divergent expression patterns of SSTRs, pro-opiomelanocortin, and gastrin mRNA. To avoid complications of hypercortisolemia, metyrapone was first administered to reduce the cortisol levels. After near-normalization of cortisol levels, transarterial chemoembolization and somatostatin analogue treatment were performed. The combination of these treatments effectively decreased ACTH and cortisol levels and also ameliorated hyperglycemia. We have achieved controlled hormone secretion and prevented tumor growth in this patient for more than 20 months, suggesting that highly individualized treatment for NET should be undertaken because of its divergent and heterogeneous characteristics.

Pancreatic endocrine tumors: a large single-center experience

OBJECTIVES

Pancreatic endocrine tumors (PETs) are infrequent, which makes large experiences unlikely. Our aim was to describe a large single-center experience with PETs and the use of endoscopic ultrasound (EUS) and a cancer staging system (TNM).

METHODS

This study involves a retrospective analysis of 86 patients (44 men; age, 58 +/- 14 years) who underwent EUS-fine needle aspiration (EUS-FNA). Immunohistochemistry was used. Lesions were classified as recommended by TNM classification.

RESULTS

Typical EUS features were well-demarcated, hypoechoic, solid, homogeneous lesions. Ninety percent had the diagnosis obtained by EUS-FNA. Twelve PETs (14%) were functioning, 8 (9.3%) were cystic, and 14 (16%) were 10 mm or smaller. Nonfunctional PETs and larger lesions were more advanced. The TNM stage was I in 24, II in 10, III in 18, and IV in 34 patients. Sixteen patients (27%) died, and 30 patients (52%) had progression/recurrence during the follow-up (34 +/- 27 months). TNM stage and surgery with curative intent were related to progression. The overall 5-year survival was 60%. The mean survival time was 94 +/- 12 months for stage I, 52 +/- 12 months for stage III, and 54 +/- 7 months for stage IV (P = 0.06).

CONCLUSIONS

Nonfunctional PETs were more common and advanced. The EUS-FNA has a high accuracy for diagnosing PETs. Progression and poorer survival were associated with TNM stage.

EUS-FNA predicts 5-year survival in pancreatic endocrine tumors

BACKGROUND

Pancreatic endocrine tumors (PETs) differ in clinical behavior and prognosis. Determination of malignant potential through specimens obtained by EUS-FNA can help in the management of these patients.

OBJECTIVE

To determine the value of EUS-FNA for diagnosing PETs and for classifying their underlying malignant potential based on the World Health Organization (WHO) classification.

DESIGN

Single-center, retrospective, cohort study.

SETTING

Tertiary referral hospital.

PATIENTS

This study involved 86 consecutive patients (44 men, mean age 58 +/- 14 years) who had been diagnosed with PETs and submitted to EUS-FNA from January 1999 to August 2008.

INTERVENTION

EUS-FNA of a pancreatic mass and/or a metastasis site. Immunohistochemistry on microbiopsies or on monolayer cytology was routinely used. The lesions were classified as recommended by the WHO.

MAIN OUTCOME MEASUREMENTS

EUS-FNA sensitivity and 5-year survival rate.

RESULTS

Overall, in 90% (77 of 86) of patients in this study, PET was diagnosed with EUS-FNA. The sensitivity did not vary with tumor size, type, location, or the presence of hormonal secretion. Of 86 patients, 30 (35%) were submitted to surgical resection. The kappa correlation index between the WHO classification obtained by EUS-FNA and by surgery was 0.38 (P = .003). Major discrepancies were found in the group of patients diagnosed with endocrine tumor of uncertain behavior by EUS-FNA, because 72% turned out to have well-differentiated endocrine carcinoma. Sixteen patients (27%) died during a mean follow-up period of 34 +/- 27 months. The 5-year survival rates were 100% for endocrine tumors, 68% for well-differentiated endocrine carcinomas, and 30% for poorly differentiated endocrine carcinomas (P = .008, log-rank test).

LIMITATIONS

Retrospective design, selection bias, and small sample size.

CONCLUSIONS

This largest single-center experience to date demonstrated the accuracy of EUS-FNA in diagnosing and determining the malignant behavior of PETs. EUS-FNA findings predict 5-year survival in patients with PETs.

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.