Long-term outcome of surgical resection in patients with gastroenteropancreatic neuroendocrine neoplasia: results from a German nation-wide multi-centric registry.

BACKGROUND: Neuroendocrine neoplasia (NEN) are rare and heterogenous tumours. Few data exist on the impact of surgical therapy. MATERIALS AND METHODS: This is a retrospective analysis of prospectively collected data of gastroenteropancreatic NEN in the German NET-Registry (1999-2012). It focuses on patients without distant metastases (limited disease, LD, stage I-IIIB). RESULTS: Data of 2239 patients with NEN were recorded. Median age was 59 years, the gender ratio was 1:1.3 (f:m). A total of 986 patients (44%) had LD, and the 5-year survival rate (5 years) was 77% for all and 90% for patients with LD. A total of 1635 patients (73%) received a surgical therapy (1st to 6th line); the 5 and 10 ysr were 83/65% after and 59/35% without surgery for all patients (p < .001). The resection margins in the LD patients were 76%, 16%, and 3% for R0, R1 and R2, respectively. The 10 ysr was 84%, 59% and 42% for R0, R1 and R2 resections, respectively (p = .021 R0/R1, p < .001 R0/R2). The R0 resection rate was 75% for G1/G2 NET and 67% for G3 NEC. CONCLUSION: The rate of complete tumour resection (R0) in LD is independent of tumour grading, and R0 resection is the key determinant of long-term survival, as demonstrated by the 10 ysr. of 84%. All NEN patients with limited disease should be considered for operation, if possible, as the best 10-year survival is shown after an R0 resection.

Syndromic versus non-syndromic sporadic gastrin-producing neuroendocrine tumors of the duodenum: comparison of pathological features and biological behavior.

Sporadic gastrin-producing neuroendocrine tumors of the duodenum present either with the Zollinger-Ellison syndrome (ZES) or with unspecific symptoms. While syndromic gastrin-producing neuroendocrine tumors often show metastases at the time of diagnosis, those without a syndrome do not. The aim of the study was to search for clinicopathological features that may distinguish the two categories of gastrin-producing duodenal tumors. In a retrospective study, we analyzed the clinical and pathological data in a series of 41 patients with syndromic (i.e., gastrinomas) or non-syndromic duodenal gastrin-producing neuroendocrine tumors (ns-gas-NETs). Twenty-four (59 %) of the 41 patients had tumors that were associated with a ZES and were classified as gastrinomas. These tumors showed a higher Ki-67 index than that of the ns-gas-NETs (1.74 vs. 0.85 %, p = 0.012). In addition, they had more lymph node metastases (75 vs. 6 %, p < 0.001) and showed liver metastases and thus presented much more frequently in TNM stage ≥III (75 vs. 6 %; p < 0.001) than their non-syndromic counterparts. Gastrinomas were removed surgically, ns-gas-NETs endoscopically. We did not observe any significant differences in overall survival or recurrence of disease. Duodenal gastrinomas show no clear morphological features that distinguish them from their non-syndromic counterparts. However, the patients with gastrinomas present in a more advanced stage of disease and need surgical treatment, while non-syndromic gastrin-producing duodenal NETs may be cured by complete endoscopical removal.

"Cherry picking", a multiple non-anatomic liver resection technique, as a promising option for diffuse liver metastases in patients with neuroendocrine tumours.

INTRODUCTION: Liver metastases of GEP-NETs are a known major prognostic factor with a strong effect on patients' survival. To date, various treatment options are available, whereas surgery remains the only curative option. Because large liver resections often cannot be performed due to insufficient remnant liver volume, a special operative technique, "cherry picking" (multiple nonanatomic liver resections), can be used as a tissue-preserving procedure. METHODS: Of 91 patients with various GEP-NETs, 16 patients were identified with synchronous or metachronous multifocal, bilobular liver metastases (>10). All were treated with "cherry picking." Patient records were reviewed retrospectively and clinical data and pathology results were analyzed. RESULTS: Mean survival after primary tumour resection was 82.8 versus 41.2 months after liver surgery. All 16 patients are still alive. Mean recurrence-free survival after primary tumour operation was 49.8 versus 24.6 months after liver surgery. Complications of cherry picking included two postoperative biliary leakages and three small hepatic abscesses (conservative/interventional approach 25 % (n = 4), surgical approach 6.25 % (n = 1). There was no postoperative mortality. Initial hormonal symptoms (5/16 patients) completely disappeared postoperatively in 2 patients and were significantly decreased in 3 patients. CONCLUSIONS: The tissue-preserving surgical technique "cherry picking" has developed due to improved imaging techniques and increased knowledge in liver anatomy, which has helped to make this approach safer and easier. Highly selected patients with multiple bilobular liver metastases of GEP-NET can benefit from this special surgical approach, also applicable for recurrent metastases.

Severe everolimus-induced steatohepatis: a case report.

The mammalian target of rapamycin inhibitors are normally favored as immunosuppressant agents for solid organ transplantation such as kidney, liver or heart. Only in recent years have they been increasingly administered for the treatment of neuroendocrine tumors. Even though mammalian target of rapamycin inhibitors are known to exhibit specific side effects, everolimus-related severe hepatic steatosis has not as yet been described in the literature. We report the case of a 76-year-old man who developed severe hepatic steatosis within four weeks of treatment with everolimus as concomitant tumor therapy for a progressively growing neuroendocrine carcinoma of the ileum. A diagnosis of hepatic steatosis was established using computer tomography and fibroscan©. Other underlying causes for steatosis hepatis could be excluded. Further studies are warranted to explain the underlying mechanisms.

Snail1 expression in colorectal cancer and its correlation with clinical and pathological parameters.

BACKGROUND: Snail1 is a transcription regulator of E-cadherin. The loss of E-cadherin seems to be a crucial step in the process of Epithelial-mesenchymal transition (EMT). EMT initiates invasion and proliferation in many tumours. Overexpression of Snail1 is known to be associated with poor outcome in several solid tumours. The aim of this study was to analyse its expression profile and prognostic significance in colorectal cancer. METHODS: Tissue microarrays (TMA) containing paraffin-embedded primary colorectal cancer (CRC) tissue samples from 251 patients were used in this study. The expression of Snail1 and E-cadherin was assessed by immunohistochemistry in different tumour compartments, corresponding lymph node metastases and normal colonic mucosa. Intensity of staining was classified according to the Remmele score (standardized scoring system) as well as the semiquantitative score established by Blechschmidt et al. RESULTS: Snail1 expression was observed in 76% of the CRC. Loss of E-cadherin was noted in 87% of the CRC. Snail1 positive tumours were significantly correlated with Snail1 positive lymph node metastases (p=0.03). There was no significant correlation between loss of E-cadherin and Snail1 expression, or between N-stage or grading and Snail1 expression. Kaplan-Meier survival analysis identified no prognostic impact of Snail1 expression on overall survival. CONCLUSION: Snail1 expression was detectable in most of the CRC but showed no significant association with E-cadherin loss, clinical pathological characteristics or overall survival. The observed loss of E-cadherin could be explained by effects of other important EMT pathways, such as the Wnt-signalling cascade.

Notch 1 tumor expression is lacking in highly proliferative pancreatic neuroendocrine tumors.

To date, very little is known about the development of benign organic hyperinsulinism and its metastatic potential. Typical morphologic, biochemical, or genetic differentiations for benign or malign tumor course of insulinomas do not exist. As signaling pathways may affect pancreatic cancer development and the maintenance of the neoplastic phenotype, the purpose of this study was to examine the role of Notch1 expression in organic hyperinsulinism. We examined 32 well-differentiated pancreatic endocrine tumors (wd PET); 11 wd PET of unknown behavior (wd PET ub); and 15 wd pancreatic endocrine cancer (wd PEC) for Notch1 expression by immunohistochemistry. Demographic data, clinical data, and follow-up of all patients were analyzed. Islets of the Langerhans show the strongest Notch1 staining in nearly 90 %. Positive Notch1 staining was absent in the acinar of the pancreas. In patients with a wd PET more than every second tumor (56.3 %/n = 18/32) demonstrated a negative Notch1 staining. The other 14 patients were positive for Notch1. Tumors of unknown behavior (wd PET ub) and malignant insulinomas had no signs of Notch expression in contrast to benign insulinomas. Considering the clinical and histomorphological tumor behavior, no correlation between Notch1 expression and clinical data was found. The missing Notch expression in the malignant tumor course might be used as a potential predictive marker, but further studies are needed to investigate the underlying molecular mechanism.

Trends in adrenal surgery: institutional review of 528 consecutive adrenalectomies.

PURPOSE: The increasing detection of adrenal tumors and the availability of a more sophisticated biochemical work-up leading to rising numbers of sub-clinical Conn's and Cushing's syndromes coincide with a rising number of adrenalectomies worldwide. The aim of our study was to report a single institution's experience with adrenal surgery. METHODS: We report data of 528 adrenalectomies, operated at our institution before and after the onset of minimally invasive endoscopic surgery (1986-1994, 1995-2008). Gender, age, indication, imaging, surgical approach, operating time, histology, tumor size, hospital stay, and complications were analyzed retrospectively. RESULTS: A total of 478 patients underwent adrenal surgery during the time observed. The average number of yearly adrenalectomies increased from 14 to 21 (p = 0.001) after the onset of laparoscopic surgery. Imaging techniques showed a significant shift towards magnetic resonance imaging (p < 0.001) and preoperative assessment of tumor size was significantly correlated to malignancy: 10.8 % (11/102) and 42 % (21/50) of tumors measuring 4-6 cm and ≥6 cm, respectively, were malignant in the final histology report (p < 0.001). Patients operated by minimally invasive endoscopy were significantly younger (mean 49.4 years, p = 0.046), had significantly shorter operating times (mean 118 min, p < 0.001), had shorter hospital stays (mean 7.1 days, p < 0.001), and had less complications (6.9 %, p = 0.004) compared to patients resected through open procedures. CONCLUSION: Although adrenalectomy rates increased and minimally invasive endoscopic surgery reduced hospital stay and complications at our institution, the yearly number of procedures was still low with often high surgical complexity. We therefore believe that adrenal surgery remains a highly specialized procedure that should preferably be performed at endocrine surgery centers.

Differentiated surgical treatment of rectovaginal fistulae.

OBJECTIVE: Rectovaginal fistulae (RVF) are a serious and debilitating problem for patients and a challenge for the treating surgeons. We present our experiences in the surgical treatment of these patients. METHODS: Study population consisted of 22 consecutive patients (range 26-70 years) with RVF treated in our department between 2003 and 2009. 13 RVF were observed after colorectal or gynaecological surgery, 3 occurred after radiotherapy, 2 due to tumour infiltration, 4 because of local inflammation (3x diverticultis, 1x ulcus simplex recti). The RVF was classified in all patients before treatment as either 'low' or 'high'. RESULTS: Local procedures (transvaginal excision, preanal repair) as initial treatment were performed in 9 patients with low fistula. In 13 cases with high fistula an abdominal approach was performed to close the fistula. A recurrence was observed in 8/22 cases (36%), which were treated by a gracilis flap (n=2), a bulbospongiosus composite (n=1), a second abdominal approach (n=4), and a re-local excision (n=1). Ultimatively, in 19 cases the defect healed but in 3 patients the RVF persisted. CONCLUSIONS: Most important predictor of healing/failure is etiology followed by localization and recurrence of the RVF. Local (preanal, transvaginal) procedures are suitable for low RVF, whereas abdominal surgery is necessary in high RVF. In recurrent RVF, muscle flaps are promising procedures.

Neuroendocrine neoplasms of the gastrointestinal tract.

BACKGROUND: Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are complex tumors whose incidence is rising and whose treatment requires precise classification and risk stratification. METHOD: Selective review of the relevant literature, including recently published guidelines. RESULTS: GEP-NENs are initially classified by their degree of histological differentiation and their graded cell proliferation (Ki-67 index). In addition, there are GEP-NEN specific TNM staging protocols. The laboratory assessment includes the measurement of general tumor markers (synaptophysin, chromogranin A) as well as specific ones (hormones). The most important imaging technique for diagnosis is octreotide scintigraphy. The surgical treatment of GEP-NEN is based on oncological resection criteria whose aim is to achieve locally radical resection while preserving as much organ function as possible. Metastases, too, may be amenable to resection. The treatment options for unresectable metastases include radiofrequency ablation and chemoembolization, both of which are palliative methods of reducing tumor volume and hormone production. Other chemotherapeutic and nuclear-medical treatments can be applied depending on the extent of metastatic spread, the proliferation index, and the degree of hormone production by the tumor. CONCLUSION: The accurate diagnosis and appropriate treatment of GEP-NET currently gives most patients with this tumor a good prognosis, as long as it is discovered early. Early GEP-NETs have a favorable prognosis. Further advances in the diagnosis and treatment of this disease may result from structural changes in patient care, including the establishment of NET centers.

Increased numbers of tumor-lysing monocytes in cancer patients.

Lymphatic infiltration is a well known phenomenon in different tumors including endocrine malignancies. However, little is known about the role of antigen-presenting cells and T cell activation in this context. The aim of our study was to investigate the quantity and function of CD14+/CD56+ monocytes in tumor patients including endocrine malignancies. First, these cells were characterized in peripheral blood of endocrine and non-endocrine cancer patients as well as in tumor tissue samples. Cancer patients had in mean 3.7 times more CD14+/CD56+ monocytes in the peripheral blood compared to healthy controls (p≤0.0001), while the highest frequencies were seen in patients with heavy tumor load. Importantly, these cells additionally expressed several NK cell markers. A proof of CD14+/CD56+ infiltrations into papillary thyroid carcinoma was shown by immunohistochemical analyses. Functional analyses revealed an apoptosis inducing capacity in vitro after IFN-α re-stimulation. Our data indicate the importance of tumor-lysing monocytes in antitumor immunity.

Chromogranin A as potential target for immunotherapy of malignant pheochromocytoma.

Currently, no effective treatment for malignant pheochromocytoma exists. The aim of our study was to investigate the role of chromogranin A (CgA) as a specific target molecule for immunotherapy in a murine model for pheochromocytoma. Six amino acid-modified and non-modified CgA peptides were used for dendritic cell vaccination. Altogether, 50 mice received two different CgA vaccination protocols; another 20 animals served as controls. In vitro tetramer analyses revealed large increases of CgA-specific cytotoxic T cells (CTL) in CgA-treated mice. Tumors of exogenous applied pheochromocytoma cells showed an extensive infiltration by CD8+ T cells. In vitro, CTL of CgA-treated mice exhibited strong MHC I restricted lysis capacities towards pheochromocytoma cells. Importantly, these mice showed strongly diminished outgrowth of liver tumors of applied pheochromocytoma cells. Our data clearly demonstrate that CgA peptide-based immunotherapy induces a cytotoxic immune response in experimental pheochromocytoma, indicating potential for therapeutic applications in patients with malignant pheochromocytoma.

Systematic comparison of sporadic and syndromic pancreatic islet cell tumors.

Pancreatic islet cell tumors (ICTs) occur as sporadic neoplasias or as a manifestation of multiple endocrine neoplasia type 1 (MEN1) and von Hippel-Lindau disease (VHL). Molecular classification of ICTs is mandatory for timely diagnosis and surveillance. Systematic comparison of VHL-ICTs and sporadic ICTs has been lacking. Our registry-based approaches used the German NET-Registry with 259 patients with neuroendocrine tumors (NETs), who were primarily diagnosed with NETs, and the German VHL-Registry with 485 molecular genetically confirmed patients who had undergone magnetic resonance imaging or computed tomography of the abdomen. All patients provided blood DNA for testing of the MEN1 and VHL genes for intragenic mutations and large deletions. In the NET-Registry, 9/101 patients (8.9%) with ICTs had germline mutations, 8 in MEN1 and 1 in VHL. In the VHL-Registry, prevalence of NETs was 52/487 (10.6%), and all were ICTs. Interestingly, of those with VHL p.R167W, 47% developed ICTs, compared to 2% of those with p.Y98H. In total, there were 92 truly sporadic, i.e. mutation-negative ICT patients. Comparing these with the 53 VHL-ICT patients, the statistically significant differences were predominance of female gender (P=0.01), multifocal ICTs (P=0.0029), and lower malignancy rate (P<0.001) in VHL-ICTs compared to sporadic cases. VHL was prevalent in <0.5% of NETs, while NETs occur in ∼10% of VHL, virtually exclusively as ICTs, which are rarely the first presentation. Patients with NETs should not be subjected to genetic testing of the VHL gene, unless they have multifocal ICTs, other VHL-associated tumors, and/or a family history for VHL.

Increased EpCAM expression in malignant insulinoma: potential clinical implications.

OBJECTIVE: EpCAM (CD326) is overexpressed in progenitor cells of endocrine pancreatic islands of Langerhans during fetal development and was suggested to act as a morphoregulatory molecule in pancreatic island ontogeny. We tested whether EpCAM overexpression is reactivated in insulinomas, endocrine tumors arising in the pancreas. DESIGN/METHOD: We used monoclonal anti-EpCAM antibody Ber-Ep4 for immunohistochemistry on formalin-fixed and paraffin-embedded tumor material. We analyzed 53 insulinomas: 40 benign (disease stage

Extrahepatic intraductal ectopic hepatocellular carcinoma: bile duct filling defect.

BACKGROUND: Obstructive jaundice caused by an intraductal hepatocellular carcinoma is a rare initial symptom. We report a rare case of an extrahepatic icteric type hepatocellular carcinoma. METHODS: A 75-year-old patient was admitted to our hospital because of obstructive jaundice 3 months after resection of multilocular hepatocellular carcinoma. A postoperative bile leakage was treated by placement of a decompressing stent in the common bile duct. Endoscopic retrograde choledochoscopy showed extended blood clots filling the bile duct system and computed tomography revealed a local swelling in the common extrahepatic bile duct. The level of alpha-fetoprotein (AFP) was only slightly elevated but that of CA19-9 was dramatically increased. Cholangiography showed an intraductal filling defect typical of a cholangiocellular carcinoma. RESULTS: Bile duct brushing cytology showed no cholangiocellular carcinoma but hepatocellular carcinoma cells in the extrahepatic bile duct. An extrahepatic bile duct resection was performed. Histological examination confirmed the diagnosis of extrahepatic intraductal growth of hepatocellular carcinoma. CONCLUSION: Ectopic hepatocellular carcinoma is a rare but important differentially diagnosed of extrahepatic bile duct filling defect.

Recurrent Fistula between Ileal Pouch and Vagina-Successful Treatment with a Gracilis Muscle Flap.

Fistulae between an ileal pouch and the vagina are an uncommon complication of ileal pouch-anal anastomosis following proctocolectomy and mucosectomy in patients with familial adenomatous polyposis coli. Several reports describe the successful use of muscle flaps to close recurrent pouch-vaginal-fistulae (PVF). However, series only contain small numbers and an optimal management has not yet been determined. We report the case of a 26-year old woman with a third recurrence of a PVF after proctocolectomy for treatment of familial adenomatous polyposis in October 2005. Because local approaches failed, definitive closure of the fistula was achieved by interposition of a gracilis muscle flap between the pouch-anal anastomosis and the vagina. The postoperative course was uneventful; the patient was discharged 7 days after surgery and remained free of recurrence and symptomatic complaints for 22 months now. The gracilis muscle flap proved to be an effective method in the treatment of recurrent PVF.

Leiomyosarcoma of the inferior vena cava: radical surgery and vascular reconstruction.

BACKGROUND: Vascular leiomyosarcoma are rare tumors typically originating from the inferior vena cava (IVC). Due to nonspecific clinical signs most tumors are diagnosed at advanced stages. Complete surgical resection remains the only potential curative therapeutic option. Surgical strategy is particularly influenced by the level of the IVC affected. Due to the topographic relation to the renal veins level-II involvement of the IVC raises special surgical challenges with respect to the maintenance of venous outflow. CASE PRESENTATION: We herein report two cases of leiomyosarcoma of the IVC with successful en bloc resection and individualized caval reconstruction. One patient presented with a large intramural and intraluminal mass and received a complete circumferential resection. Reconstruction was performed by graft replacement of the caval segment affected. The other patient displayed a predominantly extraluminal tumor growth and underwent semicircumferential resection of the IVC including the confluence of the left renal vein. In this case vascular reconstruction was performed by cavoplasty and reinsertion of the left renal vein into the proximal portion of the IVC. Resection margins of both patients were tumor free and no clinical signs of venous insufficiency of the lower extremity occurred. CONCLUSION: This paper presents two cases of successfully managed leiomyosarcomas of the vena cava and exemplifies two different options for vascular reconstruction in level II sarcomas and includes a thorough review of the literature.

Intrahepatic cholestasis without jaundice.

BACKGROUND: Cholangiocarcinoma (CC), the most common biliary tract malignancy, is frequently seen in advanced unresectable stages and is typically localized extrahepatically. Early diagnosis is unusual because of nonspecific symptoms. Painless jaundice is usually the first sign of tumor. METHOD: We present a patient with a CC (Klatskin tumor) with a complete biliary drainage by an aberrant bile duct without jaundice. RESULTS: A 67-year-old woman presented with persisting elevation of liver parameters. Diagnostic tests showed a Klatskin tumor type II. A curative right hepatic trisegmentectomy was performed after liver volume augmentation by preoperative vein embolization. CONCLUSIONS: A direct drainage of the right posterior bile duct into the common bile duct as an aberrant hepatic duct is a rare variation and is present in less than 5% of the population. In case of persistently perturbed liver function tests, an aberrant bile duct can cover up severe intrahepatic cholestasis and even obscure the diagnosis of a Klatskin tumor. Up to now it has not been described in the literature.

Insulinomatosis: a multicentric insulinoma disease that frequently causes early recurrent hyperinsulinemic hypoglycemia.

BACKGROUND: Multicentric insulinoma disease was characterized with regard to its histopathology, multiple endocrine neoplasia type 1 (MEN1) status, precursor lesions, and the risk of hyperinsulinemic hypoglycemia recurrence. METHODS: Fourteen patients with multicentric insulinoma disease were compared with 267 patients with sporadic and familial insulinomas. The tumors were classified according to the World Health Organization (WHO) criteria. The MEN1 status was defined clinically and by germline mutation analysis. Detection of the MEN1 gene locus was performed using fluorescence in situ hybridization. The surgical interventions and the duration of disease-free survival were recorded. RESULTS: Fourteen patients (5%) without evidence of MEN1 showed 53 macrotumors and 285 microtumors expressing exclusively insulin. In addition, they had small proliferative insulin-expressing monohormonal endocrine cell clusters (IMECCs). No allelic loss of the MEN1 locus was detected in 64 tumors. All but one patient had benign disease. Recurrent hypoglycemia occurred in 6/14 patients (11 recurrences; mean time to relapse 8.4 y). Thirteen patients with MEN1 (4.6%) showed 41 insulinomas and 133 tumors expressing islet hormones other than insulin. IMECCs were not detected. Allelic loss of the MEN1 locus was found in 17/19 insulinomas. Recurrent hypoglycemia occurred in 4/13 patients (4 recurrences; mean time to relapse 14.5 y). Solitary insulinomas were found in 254/281 patients (90.4%). IMECCs were absent. There was no recurrent hypoglycemia in 84 patients with benign insulinomas. CONCLUSIONS: Insulinomatosis is characterized by the synchronous and metachronous occurrence of insulinomas, multiple insulinoma precursor lesions, and rare development of metastases, but common recurrent hypoglycemia. This disease differs from solitary sporadic and MEN1-associated insulinomas.

Multiple giant scalp metastases of a follicular thyroid carcinoma.

BACKGROUND: The occurrence of skin metastases are rare events in the course of a follicular thyroid carcinoma (FTC) and usually indicate advanced tumor stages. The scalp is the most affected area of these metastases. CASE PRESENTATION: We present a case of a 76 year old Woman with multiple giant scalp metastases of a follicular carcinoma. These metastases had been resected and wounds had been closed with mesh graft. The 14-months follow up is presented. CONCLUSION: We demonstrate another case with multicentric form. Because of its location and size a primary wound closure was not possible. A healing could be reached using vacuum therapy and mesh graft transplantation.

Somatostatin-producing neuroendocrine tumors of the duodenum and pancreas: incidence, types, biological behavior, association with inherited syndromes, and functional activity.

Somatostatin-producing neuroendocrine tumors (SOM-NETs) of the duodenum and pancreas appear to be heterogeneous. To determine their clinicopathological profiles, respective data were analyzed on a series of 82 duodenal and 541 pancreatic NETs. In addition, the clinical records of 821 patients with duodenal or pancreatic NETs were reviewed for evidence of a somatostatinoma syndrome. Predominant or exclusive expression of somatostatin was found in 21 (26%) duodenal and 21 (4%) pancreatic NETs. They were classified as sporadic (n=31) or neurofibromatosis type 1 (NF1)-associated duodenal NETs (n=3), gangliocytic paragangliomas (GCPGs; n=6), or poorly differentiated neuroendocrine carcinomas (pdNECs; n=2). In addition, five duodenal and four pancreatic SOM-NETs were found in five patients with multiple endocrine neoplasia type 1 (MEN1). Metastases occurred in 13 (43%) patients with sporadic or NF1-associated SOM-NETs, but in none of the duodenal or pancreatic MEN1-associated SOM-NETs or GCPGs. Sporadic advanced (stage IV) SOM-NETs were more commonly detected in the pancreas than in the duodenum. None of the patients (including the 821 patients for whom only the clinical records were reviewed) fulfilled the criteria of a somatostatinoma syndrome. Our data show that somatostatin expression is not only seen in sporadic NETs but may also occur in GCPGs, pdNECs, and hereditary NETs. Surgical treatment is effective in most duodenal and many pancreatic SOM-NETs. MEN1-associated SOM-NETs and GCPGs follow a benign course, while somatostatin-producing pdNECs are aggressive neoplasms. The occurrence of the so-called somatostatinoma syndrome appears to be extremely uncommon.