ENETS Consensus Guidelines Update for Gastroduodenal Neuroendocrine Neoplasms

Local resection of rectal neuroendocrine tumor with first clinical manifestation of giant liver metastasis by transanal endoscopic microsurgery: A case report

RATIONALE

Rectal neuroendocrine tumor (NET) is a relatively rare tumor. Well-differentiated NETs (G1 and G2) rarely display distant metastasis at initial diagnosis. Currently, treatment for the primary lesions of rectal NETs with liver metastasis remains controversial. The liver metastasis was resected in local hospital. Transanal endoscopic microsurgery (TEM) has emerged as an effective minimally invasive surgery for local resection of lower rectal lesions. Herein, we reported the initial application of TEM to remove the rectal primary lesion in patients with low rectal NETs (G2) with giant liver metastases.

PATIENT CONCERNS

The patient, a 45-year-old woman, was primarily diagnosed with hepatocellular carcinoma and underwent curative resection of a giant liver lesion in a local hospital. Nevertheless, the postoperative pathologic examination revealed that the lesion was an NET (G2). The colonoscopy then showed a nodule 1.4 cm in diameter, 4 cm above the anal verge, located on the anterior wall of the rectum. The biopsy revealed that the nodule was also an NET (G2). However, the patient did not consent to abdominoperineal resection based on concerns for quality of life.

DIAGNOSES

Rectal NET with liver metastasis.

INTERVENTIONS

The patient underwent curative resection of liver metastasis. And, TEM was adopted to resect the primary tumor in rectum.

OUTCOMES

The patient has been disease-free for 2 years with a good quality of life and presents no local recurrence in the rectum.

LESSONS

TEM is an appropriate palliative operation for therapy of rectal NETs with distant metastases, especially for primary rectal NETs located in low rectal.

Diagnosis and Management of Upper Gastrointestinal Neuroendocrine Tumors

Upper gastrointestinal neuroendocrine tumors (NETs) are rare tumors which are increasingly recognised by practising endoscopists. After confirmation by endoscopic biopsies of these focal lesions, many questions may arise. As NETs are less frequently encountered compared to other malignancies or gastrointestinal pathology, many endoscopists may not fully understand the natural history, diagnosis and management of these tumors. In this review, we aim to update the practising endoscopist on the key clinical features and management of patients with upper gastrointestinal NET.

Neuron-Specific Enolase as an Immunohistochemical Marker Is Better Than Its Reputation

The diagnosis of neuroendocrine neoplasms (NENs) may be challenging and is based on typical morphological features and positive staining for antibodies of neuroendocrine differentiation. Neuron-specific enolase (NSE) being a cytosolic marker may be useful in this setting. NSE is by many considered nonspecific, due to the finding of this marker in tumors considered not to be of neuroendocrine origin. Our aim was to determine whether this is true and whether NSE is more specific than previously realized. We examined 178 tumors (carcinomas and NENs) from breast, lung, stomach, and kidney using immunohistochemistry with the following markers: chromogranin A, synaptophysin, CD56, secretagogin, and NSE. Expression of NSE was compared with that of the other markers. NSE was expressed in 138 (78%) of all tumors. Of the NSE-expressing tumors, 95 (68%) cases expressed one or more additional neuroendocrine markers. The staining intensity and number of NSE-expressing tumor cells were highest among tumors of neuroendocrine origin and clear cell renal cell carcinomas. A positive association was found between NSE expression and the number of additional neuroendocrine markers expressed in each of the tumors. Practically all tumors positive for an accepted neuroendocrine marker also expressed NSE.

The slow progressive nature of duodenal neuroendocrine tumor: a case report of long-term observation over 14 years

The number of duodenal neuroendocrine tumors has recently increased, but their natural history has not been well characterized. Here we report the case of a 59-year-old female undergoing complete resection by endoscopic mucosal resection after monitoring endoscopic morphologic changes and the size increment of a duodenal neuroendocrine tumor over the longest follow-up duration. An elevated lesion was initially detected on the duodenal bulb. Endoscopic biopsy from this lesion was performed three times during the follow-up, but all of the specimens simply demonstrated the presence of gastric metaplasia. Thereafter, in the esophagogastroduodenoscopy performed 14 years after the initial examination, a slight depression was detected in the center of the lesion together with an incremental change of its size. The histopathologic diagnosis of neuroendocrine tumor was made by deeper tissue sampling, and the patient subsequently underwent endoscopic mucosal resection for this tumor and was finally diagnosed with a G1 duodenal neuroendocrine tumor with pT2 cN0, cM0, stage IIa in the TNM classification. This is the first case demonstrating the slowly progressive nature of such a tumor with the longest follow-up of a duodenal neuroendocrine tumor ever reported, which could provide important information regarding the natural history and management of such tumors.

Gastrointestinal manifestations of neuroendocrine tumours: their investigation and management

The incidence of neuroendocrine tumours (NETs) is on the rise in the UK. Patients with NETs need to be managed by a team of clinical specialties. There are a number of challenging gastrointestinal (GI) manifestations related to NETs that can occur in these patients, but a limited literature base exists to guide clinicians.Whilst life expectancy can be several years for patients with NETs, the GI symptoms can have a significant impact on their quality of life. It is therefore imperative to be familiar with the common GI manifestations associated with NETs, so symptoms can be appropriately managed with an overall aim of restoring the patient's quality of life.

[Neuroendocrine neoplasia of the stomach : What is new?]

INTRODUCTION

Neuroendocrine Neoplasms are classified according to the new WHO classification in (1.) well differentiated neuroendocrine tumors G1 (NET G1, Ki67 ≤ 2 or mitosis count <2) and (2.) well differentiated neuroendocrine tumors G2 (NET G2, Ki67 3-20 or mitosis count 2-20) and (3.) poorly differentiated neuroendocrine carcinomas G3 (NEC G3, Ki67 > 20 or mitosis count >20).

MATERIAL AND METHODS

In this study 310 NENs of the Ludwig-Maximilians-University in Munich were reevaluated according to the new WHO classification.

RESULTS

7% of the analyzed NENs were presented as neoplasias of the stomach. In NENs of the stomach three distinct subtypes are recognized: (1) type 1 associated with autoimmune chronic atrophic gastritis (2) type 2, associated with multiple endocrine neoplasia (MEN1) and Zollinger-Ellison Syndrom; and (3) type 3, sporadic tumors.

DISCUSSION

Precursor lesions (i. e. hyperplasia of the ECL cells) are found in patients with hypergastrinaemia (type 1 and 2). This article should provide insights into the diagnosis of NENs of the stomach with emphasis on the new international standard.

Advances in the diagnosis and treatment of gastric neuroendocrine neoplasms

Gastric neuroendocrine neoplasms (g-NENs) are a group of heterogeneous tumors arising from the endocrine cells of stomach. Most g-NENs progresses slowly and have a long disease course; however, some other g-NENs grow rapidly, similar to the progression of gastric adenocarcinoma. g-NENs have complex and diverse clinical manifestations and their prognosis and treatment strategies depend highly on clinical subtype, pathological grade, tumour stage, and other factors. Due to their low prevalence, most clinicians have limited knowledge about g-NENs. Missed diagnosis and excessive/inadequate treatment is common in clinical settings. Thus, the diagnosis and treatment of g-NENs needs to be further standardized.

Molecular Imaging of Gastroenteropancreatic Neuroendocrine Tumors: Current Status and Future Directions

Through diagnostic imaging and peptide receptor radionuclide therapy, nuclear medicine has earned a major role in gastroenteropancreatic neuroendocrine tumors (GEP NETs). GEP NETs are diagnosed fortuitously or on the basis of symptoms or hormonal syndrome. The functional tumor characteristics shown by radionuclide imaging allow for more accurate staging and treatment selection. Tumor grade helps determine which tracer should be selected. In the past, ¹¹¹In-pentetreotide has been successful in well-differentiated (G1 and G2) tumors. However, PET/CT imaging with novel somatostatin analogs (e.g., ⁶⁸Ga-DOTATOC, ⁶⁸Ga-DOTATATE, ⁶⁸Ga-DOTANOC, and ⁶⁴Cu-DOTATATE) now offers improved sensitivity. ¹⁸F-fluorodihydroxyphenylalanine (¹⁸F-FDOPA) is another interesting radiopharmaceutical. ¹⁸F-FDOPA sensitivity is influenced by a tumor's capacity to take up, decarboxylate, and store amine precursors. ¹⁸F-FDOPA sensitivities are highest in ileal NETs and may also be helpful in insulinomas. A high uptake of ¹⁸F-FDG with a low uptake of somatostatin analog usually indicates poorly differentiated tumors (G3). Starting from these principles, this article discusses theranostic approaches to GEP NETs, taking into account both primary and metastatic lesions.

Subtype classification and management of gastric neuroendocrine neoplasms

Gastric neuroendocrine neoplasms (g-NENs) are a group of heterogeneous tumors arising from endocrine cells in the stomach. Because of the low incidence, clinical misdiagnosis and mismanagement of g-NENs may occasionally occur. In this review, I summarize the epidemiology, pathology, tumor staging, clinical classification, diagnostic algorithm, treatment and prognosis of g-NENs, to explain the standard diagnosis and management, as well as the latest advances in g-NEN research. The author advocates the four-type classification of g-NENs, and emphasizes that type 1 g-NENs are a recurrent disease which needs long-term follow-up. Molecular mechanism of recurrence of and medical therapy for type 1 g-NENs are the future research direction for neuroendocrine neoplasms.

Management of follow-up of neuroendocrine neoplasias

Neuroendocrine neoplasias (NEN) comprise heterogeneous epithelial neoplasms with a large variety of clinical presentations, treatment options and outcomes. Since potentially all NEN bear malignant potential it is important for long-term clinical management and improvement of outcome to decide on successful and oncologically and economically meaningful follow-up strategies. Evidence-based outcome data validating specific follow-up strategies are, however, not available to date and thus outcome data, known prognostic factors and clinical experience guide the decisions on follow-up regimens. The review summarizes general recommendations as well as specific considerations based on tumor entities, clinicopathological tumor characteristics and clinical experience. Follow-up shall serve the patient to improve outcome, benefit from more effective therapies and suffer less from unnecessary and/or toxic therapeutic interventions and finally preserve or gain a good quality of life.