Does Genotype-Specific Phenotype in Patients with Multiple Endocrine Neoplasia Type 2 Occur as Current Guidelines Predict?

The clinical manifestation of multiple endocrine neoplasia type 2 (MEN2) in terms of developing medullary thyroid cancer (MTC), pheochromocytoma (PCC), and/or primary hyperparathyroidism (PHPT) is related to the respective pathogenic variant of the RET proto-oncogene. The aim of this study is to retrospectively analyze the individual, genotype-dependent clinical manifestations of a large cohort of MEN2 patients. By comparing their clinical profile with currently existing evidence-based knowledge, an optimal therapy and prevention strategy in terms of prophylactic thyroidectomy and clinical follow-up could be ensured. This is a retrospective single-center study of 158 MEN2 patients who were diagnosed and/or surgically treated at a tertiary referral care center between 1990 and 2022. All participants were categorized according to their pathogenic variant of the RET proto-oncogene. Subsequently, the clinical manifestation of the disease and its time of occurrence was documented. Our analysis showed results in line with existing studies, except for a considerably lower-than-predicted occurrence of PCC in patients with V804M/L mutations. This study supports the current recommendation regarding the pathogenic variant-dependent management of this rare cancer-associated syndrome.

Persistent Hydrocephalus, Shunt, and Subglottic Stenosis in a Newborn with Plasminogen Deficiency due to Delayed Treatment with Plasminogen Concentrates: A Case Report.

INTRODUCTION: Here we present the case of a newborn baby boy with severe plasminogen deficiency causing occlusive hydrocephalus and ligneous conjunctivitis. CASE PRESENTATION: Shortly after birth, the hydrocephalus was treated with a ventriculoperitoneal shunt implantation. However, the child had to be readmitted soon afterward because of shunt obstruction. Subglottic microtrauma caused by the necessary intubations then led to another life-threatening complication - subglottic stenosis with pseudomembrane formation. Microsurgical removal had to be performed to secure the airway. Initially, regular plasma transfusions achieved slightly elevated plasminogen activity levels and short-term improvement of the respiratory situation. However, shunt dysfunction reoccurred, and alternative treatment options were needed. Since therapy with plasminogen concentrate is already available in the USA with encouraging results, this treatment option was organized in hopes of equally good results for this patient. Fortunately, under short-term substitution with plasminogen concentrates, the implantation of a new ventriculoperitoneal shunt was successful, and respiratory problems resolved. CONCLUSION: Plasminogen concentrates are critically needed in Europe and other parts of the world to improve the care of and prevent complications among patients with plasminogen deficiency.

Current Aspects of Intraoperative High-Field (3T) Magnetic Resonance Imaging in Pediatric Neurosurgery: Experiences from a Recently Launched Unit at a Tertiary Referral Center.

OBJECTIVE: To evaluate the neurosurgical and economic effectiveness of a newly launched intraoperative high-field (3T) magnetic resonance imaging (MRI) suite for pediatric tumor and epilepsy neurosurgery. METHODS: Altogether, 148 procedures for 124 pediatric patients (mean age, 8.7 years; range, 0-18 years) within a 2.5-year period were undertaken in a 2-room intraoperative MRI (iopMRI) suite. Surgery was performed mainly for intractable epilepsy (n = 81; 55%) or pediatric brain tumors (n = 65; 44%) in the supine (n = 113; 76%) and prone (n = 35; 24%) positions. The mean time of iopMRI from draping to re-surgery was 50 minutes. RESULTS: IopMRI was applied not in all but in 64 of 148 procedures (43%); in 45 procedures (31%), iopMRI was estimated unnecessary at the end of surgery based on the leading surgeon's decision. In the remaining 39 procedures (26%), ultra-early postoperative MRI was carried out after closure with the patient still sterile in the head coil. Of the 64 procedures with iopMRI, second-look surgery was performed in 26% (in epilepsy surgery in 17%, in tumor surgery in 9%). We did not encounter any infections, wound revisions, or position-related or anesthesiology-related complications. CONCLUSIONS: We used iopMRI in less than half of pediatric tumor and epilepsy surgery for which it was scheduled initially. Therefore, high costs argue against its routine use in pediatric neurosurgery, although it optimized surgical results in one quarter of patients and met high safety standards.

Pushing the Limits of the Prone Position in the Intraoperative Magnetic Resonance Suite.

BACKGROUND: Patient positioning is an integral part of surgical planning, and numerous variations have been suggested to optimize the prone position. So far, however, little attention has been given to address the restrictions and special needs in an intraoperative MRI suite. OBJECTIVE: To share our experience of transforming the modified prone position from the conventional operating room to the intraoperative MRI suite. METHODS: Two-room 3T intraoperative MRI suite. Detailed description of the technical pearls is provided. RESULTS: Ten procedures in 9 consecutive patients (2 female and 7 male) were performed. The median age was 8 years ranging from 4 to 71 years. We experienced no complication from patient positioning. Neither size (range 104-182 cm) nor weight (range 18-98 kg) of the patients was a limiting factor. In none of them, the surgeon experienced an adverse event from inadequate patient positioning and the surgical goals could be achieved without restrictions. An intraoperative MRI could be acquired in all of them with the same image quality as observed for standard positions. CONCLUSION: A transition of the modified prone position from the conventional operating room to the intraoperative MRI suite is feasible, if some crucial steps are considered. We provide a detailed technical description that could be used as a guide by others.

How to Manage Small Intestine (Jejunal and Ileal) Neuroendocrine Neoplasms Presenting with Liver Metastases?

PURPOSE OF REVIEW: Small intestinal neuroendocrine neoplasms (siNENs) are slowly growing tumours with a low malignant potential. However, more than half of the patients present with distant metastases (stage IV) and nearly all with locoregional lymph node (LN) metastases at the time of surgery. The value of locoregional treatment is discussed controversially. RECENT FINDINGS: In stage I to III disease, locoregional surgery was currently shown to be curative prolonging survival. In stage IV disease, surgery may prolong survival in selected patients with the chance to cure locoregional disease besides radical/debulking liver surgery. It may improve the quality of life and may prevent severe local complications resulting in a state of chronic malnutrition and severe intestinal ischaemia or bowel obstruction. Locoregional tumour resection offers the opportunity to be curative or to focus therapeutically on liver metastasis, facilitating various other therapeutic modalities. Risks and benefits of the surgical intervention need to be balanced individually.

Neuroendocrine liver metastasis from the small intestine: Is surgery beneficial for survival?

BACKGROUND: Neuroendocrine neoplasia of the small intestine (siNEN) are frequently diagnosed with liver metastases. The impact of the presence of liver metastases on overall survival and the necessity of surgery for liver metastasis is discussed controversially. The aim of this study is to evaluate and compare the overall long-term survival of patients with siNENs with and without liver metastasis at initial diagnosis and the possible benefit of surgical treatment as compared to active surveillance of metastases. 123 consecutive patients with siNENs were treated between 1965 and 2016. All clinical and histological records were reevaluated including analysis of the proliferation rates in all specimens. The 1-, 5-, 10- and 20-year overall survival was estimated by Kaplan-Meier analysis for patients with and without liver metastasis and according to the type of treatment (surgical vs. surveillance) of liver metastases if present. RESULTS: The 1-, 5-, 10- and 20-year overall survival rate was 89.0%, 68.4%, 52.8% and 31.0% in patients without and 89.5%, 69.5%, 33.2% and 3.6% in those with liver metastases. No statistically significant differences were observed comparing the two groups. Within the group of patients with liver metastases, the type of treatment (surgical vs. surveillance) was in favor of patients undergoing surgery. Multivariate analysis showed that the presence of liver metastases upon diagnosis was an individual risk factor associated with worse survival. CONCLUSION: The presence of liver metastasis at initial diagnosis does not have a statistically significant influence on survival. Surgery for hepatic metastasis seems to show a benefit for overall survival and may be indicated especially in patients symptomatic due to high tumor burden and serotonin hypersecretion to reduce hormone activity.

Measurements of Plasma-Free Metanephrines by Immunoassay Versus Urinary Metanephrines and Catecholamines by Liquid Chromatography with Amperometric Detection for the Diagnosis of Pheochromocytoma/Paraganglioma.

Studies conflict concerning the use of enzyme immunoassays (EIA) for plasma free metanephrines (P-MNs) vs. other methods for pheochromocytoma/paraganglioma (PPGL) diagnosis. We compared commercially available EIAs for P-MNs with high-pressure liquid chromatography (HPLC) for 24 h-urinary MNs (U-MNs) and -catecholamines (U-CATs). 943 (565 female, 378 male) patients (54 PPGL, 889 Non-PPGL) were studied. Simultaneous measurements of all parameters analyzed at the central lab of our university hospital was mandatory for inclusion. Sensitivity of P-MNs (94.4%) was similar to that of U-MNs (100%), and both were higher than of U-CATs (77.8%), specificity of P-MNs (100%) higher than of U-MNs (73.6%), and similar to U-CATs (99.8%). With the recently proposed downward adjusted ULN of P-MNs to correct for the reported negative bias of the EIAs sensitivity (98.1%) raised non-significantly, but specificity decreased significantly (94.8%). Areas under receiver-operating characteristic curves indicated comparable diagnostic performance of P-MNs (0.989) vs. U-MNs (0.995), both better than U-CATs (0.956). In summary, the EIAs to measure P-MNs performed similarly to U-MNs by HPLC, and both better than U-CATs by HPLC. The post-test probability of PPGL given a positive test result was best for P-MNs, and higher than for the other pairs of analytes. Downward corrections of ULN of P-MNs did not improve test performances.

Early Diagnosis of Medullary Thyroid Cancer: Are Calcitonin Stimulation Tests Still Indicated in the Era of Highly Sensitive Calcitonin Immunoassays?

Background: Measurements of both basal (b) calcitonin (CT) and calcium (Ca)-stimulated CT (Ca-sCT) levels are performed to identify medullary thyroid cancer (MTC) at an early stage when used as part of the diagnostic workup of thyroid nodules (CT screening). Novel immunochemiluminometric assays, which are highly sensitive and specific for monomeric CT and avoid cross-reactivity, have been introduced over the past decade. No prospectively generated data have so far become available to answer the frequently raised question as to whether Ca-sCT in contrast to bCT alone is helpful and, therefore, still indicated for the early detection of MTC. Methods: Ca-stimulation tests were performed in 149 consecutive patients with thyroid nodules and elevated bCT. Regardless of Ca-sCT levels, all patients had an operation applying a uniform surgical protocol, including thyroidectomy and systematic lymph node dissection. Recently published sex-specific cutoff levels for the differentiation of MTC and other C-cell pathologies (C-cell hyperplasia [CCH]) were used to compare the diagnostic performance of bCT or Ca-sCT alone and in combination using receiver-operating characteristic (ROC) analysis. In addition, CT cutoff levels to predict lateral lymph node metastasis were evaluated for bCT compared with Ca-sCT. Follow-up for all patients was documented and correlated with initial CT levels. Results: MTC was identified in 76 (50.1%) patients, in 21/76 (27.6%) with lymph node and in 4 (5.3%) with distant metastasis. Using predefined cutoff levels, patients could effectively be subdivided into a group above the cutoff level with definitive diagnosis of MTC (100%) and below (gray zone) with a significant overlap of CCH and MTC (all classified as pT1a; males: 19/58 [37.5%], females: 7/41 [17.1%]). The areas under the ROC curve (AUC) were excellent for the diagnosis of MTC in all tests. Determination of bCT proved to be superior for both diagnosing MTC in males (AUC for bCT: 0.894; AUC for Ca-sCT: 0.849) and females (bCT: 0.935; Ca-sCT: 0.868) and also for diagnosing lymph node metastasis in the lateral compartment (males: bCT: 0.925; Ca-sCT: 0.810; females: bCT: 0.797; Ca-sCT: 0.674). Combining both tests did not improve diagnostic accuracy. Using a cutoff level of >85 pg/mL for females and >100 pg/mL for males, the sensitivity for diagnosing lateral neck lymph node metastasis was 100%. Below these cutoff levels, no patient showed persistent or recurrent disease (median follow-up: 46 [ ± 27] months). Conclusions: Predefined sex-specific bCT cutoff levels are helpful for the early detection of MTC and for predicting lateral neck lymph node metastasis. Ca-sCT did not improve preoperative diagnostics. bCT levels >43 and >100 pg/mL for males and of >23 and >85 pg/mL for females are relevant for advising patients and planning the extent of surgery.

The determination of real fluid requirements in laparoscopic resection of pheochromocytoma using minimally invasive hemodynamic monitoring: a prospectively designed trial.

BACKGROUND: Hemodynamic instability is frequently observed during adrenalectomy for pheochromocytoma (PCC). Guidelines recommend liberal preoperative volume administration. However, it is unclear whether fluid deficiency or vasoplegia causes shifting hemodynamics and whether minimally invasive hemodynamic monitoring with esophageal Doppler (EDM) can help visualize intraoperative changes avoiding volume overload and complications. METHODS: Ten patients with biochemically verified PCC and five patients with hormonally inactive adrenal tumors (HIAT; control group) were treated following a strict protocol. During laparoscopic adrenalectomy, goal-directed fluid therapy was performed using EDM. Hemodynamic and biochemical data were documented. The primary outcome variables were fluid requirement and hemodynamic parameters. RESULTS: Applying EDM, total intraoperative fluid administration was slightly higher in PCC patients than in patients with HIAT (2100 ± 516 vs. 1550 ± 622 ml, p = 0.097; 12.9 ± 4.8 vs. 8.3 ± 0.7 ml kg-1 h-1, p = 0.014). Hemodynamics varied considerably within the PCC group and was associated with type and level of secreted catecholamines. Arterial blood pressure and systemic vascular resistance index reached their minimum in the 10-min period after resection of PCC. Without liberal fluid administration, an increase in cardiac index was observed in both groups comparing baseline measurements to end of surgery. This increase was statistically significant only in PCC patients (PCC: 2.31 vs. 3.15 l min-1 m-2, p = 0.005; HIAT: 2.08 vs. 2.56 l min-1 m-2, p = 0.225). CONCLUSIONS: As vasoplegia, but not hypovolemia, was documented after tumor resection, there is no evidence that PCC patients profit from liberal fluid administration during laparoscopic adrenalectomy. To avoid volume overload, noninvasive techniques such as EDM should be routinely used to visualize the variable intraoperative course. TRIAL REGISTRATION: ClinicalTrials.gov, Identifier: NCT01425710.

Effectiveness of anti-osteoporotic treatment after successful parathyroidectomy for primary hyperparathyroidism: a randomized, double-blind, placebo-controlled trial.

PURPOSE: After successful surgery for primary hyperparathyroidism, bone mineral density (BMD) does not improve equally in all patients. As no trial has so far aimed to influence normalization of BMD, it was the goal of this investigation to determine whether pharmacological treatment is effective in improving regain of BMD after successful parathyroidectomy in patients with preoperatively diagnosed osteoporosis or osteopenia and to evaluate when treatment may be indicated. METHODS: In this randomized, placebo-controlled, double-blind trial, 52 patients were treated with strontium ranelate 2 g daily + 1000 mg calcium + 800 IU vitamin D (strontium group; SG) or with 1000 mg calcium + 800 IU vitamin D alone (placebo group; PG) for 1 year. The main outcome measures were BMD (lumbar spine, femoral neck, radius) and bone turnover markers. RESULTS: The baseline characteristics were similar in both groups. Absolute BMD (1.007 ± 0.197 vs. 0.897 ± 0.137 g/cm2; p = 0.024) and both relative (9.94 vs. 3.94%; p < 0.001) and absolute (0.09 ± 0.06 vs. 0.03 ± 0.04 g/cm2; p < 0.001) changes in lumbar-spine BMD were significantly higher in the SG than in the PG. Compared to baseline, BMD significantly increased in both groups at the lumbar spine (p < 0.001 and p = 0.001, respectively) and femoral neck (both p < 0.001), whereas radius BMD only changed significantly in the SG. However, the proportion of patients with osteoporosis/osteopenia significantly declined only at the lumbar spine in the SG (from 69.0 to 37.9%; p = 0.034), whereas no decrease was found in the PG. No severe adverse events occurred. CONCLUSIONS: Postoperative anti-osteoporotic treatment can positively influence regain of BMD mainly in the lumbar spine and should be considered. Without treatment, most patients and especially those with low preoperative markers of bone turnover remained osteoporotic/osteopenic 1 year after surgery.

Intertumor heterogeneity in 60 pancreatic neuroendocrine tumors associated with multiple endocrine neoplasia type 1.

BACKGROUND: Patients with multiple endocrine neoplasia type 1 (MEN-1) develop multiple pancreatic neuroendocrine neoplasias (PNENs). Size at diagnosis and growth during follow-up are crucial parameters. According to the WHO 2017, grading is another important parameter. The impact of grading compared to size (WHO 2000) on the clinical course needs to be evaluated. METHODS: Sixty PNENs of six patients with MEN-1 were retrospectively evaluated. RESULTS: Fifty-one tumors with a diameter of < 20 mm were graded as G1. Two of 9 tumors with diameters of ≥20 mm were graded as G2. Tumor size of ≥20 mm correlated significantly with higher proliferation (p = 0.000617). Lymph node metastases were documented in two patients with a total of 19 tumors. In one patient, all 13 tumors (diameter: 0.4 to 100 mm) were classified as G1. However, metastases were documented in 9/29 lymph nodes. In the other patient, 5 tumors (3.5 to 20 mm) were classified as G1. The sixth tumor (30 mm) was classified as G2 (Ki-67: 8%). Metastases were revealed in 2/20 lymph nodes. CONCLUSIONS: Tumor size of ≥20 mm seems to correlate with more aggressive MEN-1 related pancreatic disease, regardless of individual proliferation. Tumors ≥20 mm and tumors graded as G2 should be treated surgically regardless of their size.

Calcium-stimulated calcitonin - The "new standard" in the diagnosis of thyroid C-cell disease - clinically relevant gender-specific cut-off levels for an "old test".

INTRODUCTION: Pentagastrin (Pg) stimulated calcitonin (sCT) was used to enhance accuracy in medullary thyroid cancer (MTC) diagnosis. As it is now unavailable, calcium (Ca) has been recommended as an alternative. The aim of this study was to define gender-specific cut-off values to predict MTC in patients with elevated basal CT (bCT) following Pg-sCT and Ca-sCT stimulation and to compare the time courses of CT release during stimulation. MATERIALS AND METHODS: The stimulation tests were applied in 62 consecutive patients with thyroid nodules. Basal calcitonin was measured by chemiluminescent immunometric assay. All patients underwent thyroidectomy and bilateral central neck dissection. C-cell pathology was confirmed by histological and immunohistochemical evaluation. RESULTS: In 39 (0.63) patients MTC was documented while isolated C-cell hyperplasia (CCH) was identified in 23 (0.37) patients. Medullary thyroid cancer was predicted in males with bCT values > 43 pg/mL or sCT concentrations > 470 pg/mL (Pg-sCT) or > 1500 pg/mL (Ca-sCT), and in females with bCT concentrations > 23 pg/mL or sCT concentrations > 200 pg/mL (Pg-sCT) or > 780 pg/mL (Ca-sCT), respectively. Pg-sCT correctly predicted MTC in 16 (0.66) compared to 13 (0.54) after Ca-sCT in males and in 12 (0.80) compared to 11 (0.73) in females; without statistical significance. In patients with CCH or low tumor burden, there was a tendency of faster CT release after Ca stimulation (CT peak after 3min in > 60%) compared to patients with advanced MTC (CT peak after 3min in < 10%). CONCLUSIONS: Using gender-specific cut-off values, Ca could replace Pg to predict MTC with similar diagnostic power.

Medullary Thyroid Carcinoma: Do Ultrasonography and F-DOPA-PET-CT Influence the Initial Surgical Strategy?

BACKGROUND: At the time of diagnosis, one-third of medullary thyroid carcinoma (MTC) patients show lymph node (LN) or distant metastasis. A metastasized MTC requires different surgical strategies. OBJECTIVE: This study aimed to determine the value of ultrasound and [18F]fluoro-dihydroxyphenylalanine positron emission tomography with computed tomography (F-DOPA-PET-CT) in localizing MTC, as well as LN and distant metastasis. METHODS: The study included 50 patients (24 males/26 females) with preoperative ultrasound, F-DOPA-PET-CT, and histologically proven MTC. Imaging results were correlated with both preoperative basal calcitonin (bCt) levels and final histology. RESULTS: Tumors were classified as pT1a:17 (diameter, mean ± standard deviation: 5.8 ± 3.0 mm), pT1b:15 (15.0 ± 3.2 mm), pT2:9 (27.3 ± 7.0 mm), and pT3:9 (38.3 ± 24.2 mm). The median bCt level was 202 pg/mL (lower/upper quartile: 82/1074 pg/mL). Ultrasound was positive for tumor in 45/50 (92%) patients (20.0 ± 16.0 mm) and negative in 5 patients (3.2 ± 2.2 mm). Overall, 43/50 (86%) patients had positive F-DOPA local scans (20.0 ± 16.4 mm), while 7 (14%) patients were negative (7.7 ± 8.1 mm). Lastly, 21/50 (42%) patients had LN metastasis; 8/21 (38%) patients had positive LNs suspected with ultrasound, and 12/21 (57%) patients had positive LNs suspected with F-DOPA. Tumor and LN sensitivity of ultrasound was 92% and 43%, respectively, and 86% and 57% of F-DOPA-PET-CT, respectively. In 3/50 (6%) patients and 3/50 (6%) patients, mediastinal LN metastasis and distant metastasis, respectively, were diagnosed only by F-DOPA-PET-CT. CONCLUSION: Ultrasound and F-DOPA-PET-CT are sensitive for the localization of MTC but not for the presence and location of LN metastasis (limitations: size/number). Only F-DOPA ensures the diagnosis of distant metastasis and influences the extent of LN surgery. Surgical strategy cannot be predicted based on neither ultrasound nor F-DOPA-PET-CT.

Surgical Treatment of Small Intestinal Neuroendocrine Tumors G1/G2.

Although the majority of neuroendocrine tumors of the small intestine (siNETs) classified as low-grade G1 or G2 show slow local growth, they are frequently diagnosed at an advanced stage of metastatic disease. The surgical treatment is curative in stages I-III or palliative in stage IV in an attempt to avoid local complications of bowel obstruction and ischemia of the small bowel by unremoved lymph node metastases. Individualized surgical procedures performed by experienced surgeons considering tumor multifocality and the primary extent of lymph node metastases along the mesenteric vessels are recommended to remove as much tumor volume as possible, while avoiding major complications intraoperatively and small bowel syndrome postoperatively.

Diagnosis and treatment of gastroenteropancreatic neuroendocrine tumors: current data on a prospectively collected, retrospectively analyzed clinical multicenter investigation.

BACKGROUND: The aim of this prospectively collected, retrospectively analyzed clinical investigation was to describe "unmasked" clinical symptoms and methods of diagnosis, treatment, and short-term follow-up of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) diagnosed during 1 year in Austria. METHODS: In total, 277 patients with GEP-NETs were documented. All tumors were immunhistochemically defined according to recently summarized criteria (World Health Organization, European Neuroendocrine Tumour Society). A standardized questionnaire comprising 50 clinical and biochemical parameters (clinical symptoms, mode of diagnosis, treatment, follow-up) was completed by attending physicians. RESULTS: The most common initial symptoms were episodes of abdominal pain, diarrhea, weight loss, gastrointestinal bleeding, flushing, and bowel obstruction. Overall, 48.1% of tumors were diagnosed by endoscopy, 43.7% were diagnosed during surgery, 5% were diagnosed by fine-needle aspiration of the primary or metastases, and 2.5% were diagnosed during autopsy; 44.5% of tumors were not suspected clinically and were diagnosed incidentally during various surgical procedures. Overall, 18.7% of tumors were removed endoscopically and 67.6% were removed surgically; 13.7% of patients were followed without interventional treatment. Endoscopic or surgical intervention was curative in 81.4% of patients and palliative in 18.6% of patients. At the time of diagnosis, information on metastasis was available in 83.7% of patients with malignant NETs. Lymph node or distant metastases were documented in 74.7% of patients. In 19.3% of patients, 41 secondary tumors were documented, with 78.0% classified histologically as adenocarcinomas. CONCLUSION: This investigation summarizes the clinical presentation and current practice of management of GEP-NETs and thereby extends the understanding and clinical experience.

Gastroenteropancreatic neuroendocrine tumours: the current incidence and staging based on the WHO and European Neuroendocrine Tumour Society classification: an analysis based on prospectively collected parameters.

As incidence data on gastroenteropancreatic neuroendocrine tumours (GEP-NETs) have so far only been retrospectively obtained and based on inhomogeneous material, we conducted a prospective study in Austria collecting all newly diagnosed GEP-NETs during 1 year. Using the current WHO classification, the tumor, nodes, metastases (TNM) staging and Ki67 grading and the standard diagnostic procedure proposed by the European Neuroendocrine Tumor Society (ENETS), GEP-NETs from 285 patients (male: 148; female: 137) were recorded. The annual incidence rates were 2.51 per 100,000 inhabitants for men, 2.36 per 100,000 for women. The stomach (23%) was the main site, followed by appendix (21%), small intestine (15%) and rectum (14%). Patients with appendiceal tumours were significantly younger than patients with tumours in any other site. About 46.0% were classified as benign, 15.4% as uncertain, 31.9% as well differentiated malignant and 6.7% as poorly differentiated malignant. Patients with benign or uncertain tumours were significantly younger than patients with malignant tumours. Among the malignant tumours of the digestive tract, 1.49% arose from neuroendocrine cells. For malignant gastrointestinal NETs, the incidence was 0.80 per 100,000: 40.9% were ENETS stage I, 23.8% stage II, 11.6% stage III and 23.8% stage IV. The majority (59.7%) were grade 1, 31.2% grade 2 and 9.1% grade 3. NETs of the digestive tract are more common than previously reported; the majority show benign behaviour, are located in the stomach and are well differentiated. G3 tumours are very rare.