Pathology reporting of neuroendocrine tumors: essential elements for accurate diagnosis, classification, and staging

Rectal neuroendocrine tumor during anorectal surgery: three case reports and a review of the literature

Background

Rectal neuroendocrine tumors (NET) are thought to originate from the diffuse neuroendocrine system. The lack of apparent signs of illness and the patient's non-specific presentations often cause a delay in diagnosis, until in their final stages of cancer. Thus, rectal NETs pose a significant challenge to most physicians.

Case presentation

This article presents three cases of rectal NETs discovered during anorectal surgery. Owing to their atypical symptoms, they were initially diagnosed as mixed hemorrhoids or perianal fistulas. However, the patients were diagnosed with rectal NETs and thus underwent endoscopic dissection or transanal endoscopic microsurgery. Histological analysis revealed three rectal NETs, one G1 and two G2. All patients were followed-up for more than 6 months, with excellent outcomes without recurrence.

Conclusions

The etiology, pathogenesis, therapeutic methods, prevention, and prognosis of rectal NETs remain challenging. Given the variable understanding of the most appropriate operative approaches for rectal NETs, our objective was to broaden the perspective of this infrequent disease by delivering distinctive individual experiences and emphasizing the therapeutic significance of delicate surgery.

Risk Factor Analysis of Lymph Node Metastasis for Rectal Neuroendocrine Tumors: Who Needs a Radical Resection in Rectal Neuroendocrine Tumors Sized 1-2 cm?

BACKGROUND

Rectal neuroendocrine tumors (NETs) have malignant potential, and lymph node (LN) or distant metastases can occur; however, treatment of NETs 1-2 cm in size is controversial.

OBJECTIVE

This study aimed to identify predictive factors for LN metastasis and prognostic factors for recurrence of rectal NETs, especially tumors 1‒2 cm in size.

METHODS

Between October 2004 and November 2020, 453 patients underwent endoscopic or surgical treatment for rectal NETs in Seoul National University Hospital. The data on these patients were prospectively collected in our database and reviewed retrospectively. In cases of local excision, we evaluated LN metastasis with radiologic imaging, including computed tomography or magnetic resonance imaging before treatment and during the follow-up periods.

RESULTS

LN metastasis was observed in 40 patients (8.8%). A higher rate of LN metastasis was observed in larger-sized tumors, advanced T stage, lymphovascular invasion (LVI), perineural invasion (PNI), and high tumor grade. In multivariable analysis, the significant risk factors for LN metastasis were tumor size (1 ≤ size < 2 cm: hazard ratio [HR] 64.07; size ≥2 cm: HR 102.37, p < 0.001) and tumor grade (G2: HR 3.63, p = 0.034; G3: HR 5.09, p = 0.044). In multivariable analysis for tumors 1-2 cm in size, the risk factor for LN metastasis was tumor grade (G2: HR 6.34, p = 0.013).

CONCLUSIONS

Tumor grade and size are important predictive factors for LN metastasis. In NETs 2 cm in size, tumor grade is also important for LN metastasis, and radical resection should be considered.

Approaching Small Neuroendocrine Tumors with Radiofrequency Ablation

In recent years, small pancreatic neuroendocrine tumors (pNETs) have shown a dramatic increase in terms of incidence and prevalence, and endoscopic ultrasound (EUS) radiofrequency ablation (RFA) is one potential method to treat the disease in selected patients. As well as the heterogeneity of pNET histology, the studies reported in the literature on EUS-RFA procedures for pNETs are heterogeneous in terms of ablation settings (particularly ablation powers), radiological controls, and radiological indications. The aim of this review is to report the current reported experience in EUS-RFA of small pNETs to help formulate the procedure indications and ablation settings. Another aim is to evaluate the timing and the modality of the radiological surveillance after the ablation. Moreover, new studies on large-scale series are needed in terms of the safety and long-term oncological efficacy of RFA on these small lesions.

Prognostic Value of Somatostatin Receptor-Derived Volumetric Parameters from a Hybrid Standardized Uptake Value Thresholding Method in Patients with 68Ga-DOTATATE-Avid Stage IV Neuroendocrine Neoplasms: A Preliminary Study

INTRODUCTION

The ability of PET/CT imaging to delineate neuroendocrine neoplasms (NENs) and predict prognosis in affected patients is often compromised by substantial uptake heterogeneity. We hereby proposed a hybrid standardized uptake value (SUV) thresholding algorithm to extract volumetric parameters from somatostatin receptor (SSTR) PET/CT imaging and investigate their prognostic performance in patients with 68Ga-DOTATATE-avid stage IV NENs.

METHODS

For 38 retrospectively enrolled patients, we used either fixed SUV thresholding of normal liver parenchyma (method A), 41% of the SUVmax for each lesion (method B), or a hybrid method (method A for liver metastases; fixed SUV threshold of normal bone for bone metastases; method B for primary tumors and other metastases) to quantify the whole-body SSTR-expressing tumor volume (SRETVwb) and total lesion SSTR expression (TLSREwb). Patient survival was also recorded and analyzed.

RESULTS

PET/CT images revealed heterogeneous uptake of 68Ga-DOTATATE at primary and metastatic sites. Progression-free survival (PFS) and overall survival (OS) were negatively correlated with the extent of liver or bone metastases (p < 0.05), but not significantly correlated with tumor grade or 18F-FDG PET/CT positivity. By the hybrid method, PFS was significantly shorter in patients with high SRETVwb, and OS was significantly shorter in those with high SRETVwb and TLSREwb (p < 0.05). However, when derived from method A or method B, neither SRETVwb nor TLSREwb could predict patient outcomes.

CONCLUSION

Compared with other methods used in 68Ga-DOTATATE-avid stage IV NENs, our hybrid SUV thresholding method demonstrated robustness, with greater precision, reliability, and prognostic power.

The Glasgow Prognostic Score Predicts Survival Outcomes in Neuroendocrine Neoplasms of the Gastro-Entero-Pancreatic (GEP-NEN) System

Background: Across a variety of solid tumors, prognostic implications of nutritional and inflammation-based risk scores have been identified as a complementary resource of risk stratification. Methods: In this retrospective study, we performed a comparative analysis of several established risk scores and ratios, such as the Glasgow Prognostic Score (GPS), in neuroendocrine neoplasms of the gastro−entero−pancreatic (GEP-NEN) system with respect to their prognostic capabilities. Clinicopathological and treatment-related data for 102 GEP-NEN patients administered to the participating institutions between 2011 and 2021 were collected. Scores/ratios significantly associated with overall or progression-free survival (OS, PFS) upon univariate analysis were subsequently included in a Cox-proportional hazard model for the multivariate analysis. Results: The median age was 62 years (range 18−95 years) and the median follow-up period spanned 51 months. Pancreatic or intestinal localization at the initial diagnosis were present in 41 (40.2%) and 44 (43.1%) cases, respectively. In 17 patients (16.7%), the primary manifestation could not be ascertained (NNUP; neuroendocrine neoplasms of unknown primary). Histological grading (HG) revealed 24/102 (23.5%) NET/NEC (poorly differentiated; high grade G3) and 78/102 (76.5%) NET (highly or moderately differentiated; low−high grade G1−G2). In total, 53/102 (51.9%) patients presented with metastatic disease (UICC IV), 11/102 (10.7%) patients presented with multifocal disease, and 56/102 (54.9%) patients underwent a primary surgical or endoscopic approach, whereas 28 (27.5%) patients received systemic cytoreductive treatment. The univariate analysis revealed the GPS and PI (prognostic index), as well as UICC-stage IV, HG, and the Charlson comorbidity index (CCI) to predict both the PFS and OS in GEP-NEN patients. However, the calculation of the survival did not separate GPS subgroups at lower risk (GPS 0 versus GPS 1). Upon the subsequent multivariate analysis, GPS was the only independent predictor of both OS (p < 0.0001; HR = 3.459, 95% CI = 1.263−6.322) and PFS (p < 0.003; HR = 2.119, 95% CI = 0.944−4.265). Conclusion: In line with previous results for other entities, the present study revealed the GPS at baseline to be the only independent predictor of survival across all stages of GEP-NEN, and thus supports its clinical utility for risk stratification in this group of patients.

A Machine Learning Decision Support System (DSS) for Neuroendocrine Tumor Patients Treated with Somatostatin Analog (SSA) Therapy

The application of machine learning (ML) techniques could facilitate the identification of predictive biomarkers of somatostatin analog (SSA) efficacy in patients with neuroendocrine tumors (NETs). We collected data from 74 patients with a pancreatic or gastrointestinal NET who received SSA as first-line therapy. We developed three classification models to predict whether the patient would experience a progressive disease (PD) after 12 or 18 months based on clinic-pathological factors at the baseline. The dataset included 70 samples and 15 features. We initially developed three classification models with accuracy ranging from 55% to 70%. We then compared ten different ML algorithms. In all but one case, the performance of the Multinomial Naïve Bayes algorithm (80%) was the highest. The support vector machine classifier (SVC) had a higher performance for the recall metric of the progression-free outcome (97% vs. 94%). Overall, for the first time, we documented that the factors that mainly influenced progression-free survival (PFS) included age, the number of metastatic sites and the primary site. In addition, the following factors were also isolated as important: adverse events G3-G4, sex, Ki67, metastatic site (liver), functioning NET, the primary site and the stage. In patients with advanced NETs, ML provides a predictive model that could potentially be used to differentiate prognostic groups and to identify patients for whom SSA therapy as a single agent may not be sufficient to achieve a long-lasting PFS.

The panel of syntaxin 1 and insulinoma-associated protein 1 outperforms classic neuroendocrine markers in pulmonary neuroendocrine neoplasms

Syntaxin-1 (STX1) is a recently described highly sensitive and specific neuroendocrine marker. We evaluated the applicability of STX1 as an immunohistochemical marker in pulmonary neuroendocrine neoplasms (NENs). We compared STX1 with established neuroendocrine markers, including insulinoma-associated protein 1 (INSM1). Typical carcinoids (n = 33), atypical carcinoids (n = 7), small cell lung carcinomas ([SCLCs] n = 30), and large cell neuroendocrine lung carcinomas (n = 17) were immunostained using tissue microarray for STX1, chromogranin A, synaptophysin, CD56, and INSM1. Eighty-four of eighty-seven (96.5%) NENs showed STX1 positivity. Carcinoids and LCNECs typically presented a combined strong membranous and weak cytoplasmic staining pattern; cytoplasmic expression was predominately observed in SCLCs. The sensitivity of STX1 was 90% in SCLCs and 100% in typical carcinoids, atypical carcinoids, and large cell neuroendocrine lung carcinomas. The overall sensitivity of STX1 in pulmonary NENs was 96.6%, and the sensitivity of the other markers was as follows: chromogranin A (85.2%), synaptophysin (85.2%), CD56 (92.9%), and INSM1 (97.7%). STX1 was found to be an excellent neuroendocrine marker of pulmonary NENs, with sensitivity and specificity surpassing that of classic markers. We propose a panel of STX1 and INSM1 for the routine immunohistochemical workup of pulmonary NENs.

Clinicopathological analysis of 250 cases of pituitary adenoma under the new WHO classification

Pituitary adenomas (PAs) are a common subtype of intracranial tumors. The aim of the present study was to analyse the clinical and pathological features of different types of pituitary adenomas (PAs) according to the 2017 World Health Organisation Endocrine Organ Tumor Classification guidelines. The clinical data of 250 patients with PAs were collected and analysed. Differences in the incidence of invasion, recurrence and apoplexy in patients between high- and low-risk PAs were compared, as were differences in the Ki-67 index between invasive and non-invasive PAs and between recurrent PAs and non-recurrent PAs. Of the 250 cases, 45 cases were diagnosed as somatotroph adenomas, 26 cases as lactotroph adenomas, 1 case as thyrotroph adenoma, 61 cases as corticotroph adenomas, 93 cases as gonadotropin adenomas, 15 cases as null cell adenomas and 9 cases as plurihormonal adenomas. There were 5 types of high-risk pituitary adenoma identified: 17 cases of sparsely granulated somatotroph adenoma, 11 cases of lactotroph adenoma in men, 3 cases of plurihormonal PIT-1 positive adenoma and 42 cases of silent corticotroph adenoma. Crooke's cell adenoma was not identified. High-risk PAs had significantly higher rates of invasion, recurrence and apoplexy compared with that in low-risk types (P<0.001). Invasive PAs had a significantly higher Ki-67 index compared with that in non-invasive PAs (3.5±1.8 vs. 2.8±1.3; P<0.01). Recurrent PAs had a significantly higher Ki-67 index compared with that in non-recurrent PAs (3.9±1.9 vs. 2.8±1.3; P<0.001). According to the 2017 classification criteria, patients most frequently had gonadotrophin cell adenomas, followed by corticotroph adenomas and the proportion of null cell adenomas was reduced. Differences were noted in the proliferation, recurrence and apoplexy characteristics of high-risk PAs and low-risk PAs. The invasion and recurrence of PAs were found to be related to the Ki-67 index.

The North American Neuroendocrine Tumor Society Consensus Paper on the Surgical Management of Pancreatic Neuroendocrine Tumors

This manuscript is the result of the North American Neuroendocrine Tumor Society consensus conference on the surgical management of pancreatic neuroendocrine tumors from July 19 to 20, 2018. The group reviewed a series of questions of specific interest to surgeons taking care of patients with pancreatic neuroendocrine tumors, and for each, the available literature was reviewed. What follows are these reviews for each question followed by recommendations of the panel.

The Correlation Between [68Ga]DOTATATE PET/CT and Cell Proliferation in Patients With GEP-NENs

PURPOSE

Objectives of the study are to analyze the correlation between [68Ga]DOTATATE positron emission tomography (PET)/X-ray computed tomography (CT) measurements and various biological characteristics of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs), and to determine optimal cutoff value of SUVmax (standard uptake value) to differentiate neuroendocrine tumors (NETs) and neuroendocrine cancers (NECs).

PROCEDURES

Of the GEP-NEN cases (73 males, 53 females; age 18-77 years) with pathologically proven primary and/or metastatic lesions, 126 were studied. All of the short axes of lesions were larger than 0.5 cm in order to avoid the partial volume effect. Patients fasted for 6 h before the PET/CT scans. The dose of [68Ga]DOTATATE was 100-200 MBq and the acquisition began at 1 h after injection. The lesion with the highest SUVmax in each patient was analyzed.

RESULTS

In the total sample, the sensitivity of [68Ga]DOTATATE was 69.05 %. The sensitivities were significantly different among G1, G2, and G3 groups (72.22 %, 91.53 %, and 40.82 %, respectively; p < 0.01). The SUVmax of the G3 group was lowest. We also found that the sensitivity and SUVmax were significantly higher (p < 0.05) in patients with pancreatic NENs (Pan-NENs) than in patients with gastrointestinal NENs (Gi-NENs) and unknown primary NENs (Up-NENs). A significant negative correlation between SUVmax and Ki-67 was found (r = - 0.429, p < 0.01). Using SUVmax to differentiate neuroendocrine tumors (NETs) and neuroendocrine cancers (NECs), the area under the ROC curve (AUC) was 0.771 and the cutoff value of SUVmax was 11.25 (sensitivity 79.2 %, specificity 65.3 %). However, Pan-NENs did not show any statistical significance results in correlation and ROC analysis.

CONCLUSION

[68Ga]DOTATATE PET/CT results showed a negative correlation with GEP-NEN cell proliferation and were complementary to Ki-67. Pan-NENs were different from Gi-NENs and Up-NENs when compared to somatostatin receptor expression.

Vasoactive Intestinal Peptide-Secreting Tumors: A Review

Vasoactive intestinal peptide-secreting tumors (VIPomas) are a group of rare neuroendocrine tumors, which cause a typical syndrome of watery diarrhea. Most of these tumors are found in the pancreas and are usually detected at a later stage. Although curative resection is not possible in most of these tumors, both symptom and tumor control can be achieved by a multidimensional approach, to enable a long survival of most patients. There are no clear-cut guidelines for the management of VIPomas because of the rarity of this neoplasm and lack of prospective data. In this review, we discuss the available evidence on the clinical features and management of these rare tumors.

Vitamin D and vitamin B12 deficiencies in patients with small intestinal carcinoid tumour: is opioid use disorder a confounding factor in the diagnosis?

Carcinoid tumours have the ability to secrete various peptides and bioamines that lead to carcinoid syndrome manifested as cutaneous flushing, diarrhoea, bronchial constriction and cardiac involvement. The deficiencies of vitamins D and B₁₂ have previously been reported in patients with carcinoid tumours presumably due to chronic diarrhoea associated with the carcinoid syndrome. Herein, we chronicle the case of a patient with opioid use disorder who presented with small bowel obstruction that was found to be caused by a midgut carcinoid tumour. Laboratory studies revealed deficiencies of vitamins D and B₁₂ even though he denied diarrhoea and had no other aetiology of deficiencies of these vitamins. Additionally, this paper presents a review of the published medical literature pertaining to clinical features, diagnostic investigations and treatment of intestinal carcinoid tumours and explores possible explanations for the observed deficiencies in these patients.

[68Ga]-Dota Peptide PET/CT in Neuroendocrine Tumors: Main Clinical Applications

Objective:

Neuroendocrine Neoplasms (NENs) are generally defined as rare and heterogeneous tumors. The gastrointestinal system is the most frequent site of NENs localization, however they can be found in other anatomical regions, such as pancreas, lungs, ovaries, thyroid, pituitary, and adrenal glands. Neuroendocrine neoplasms have significant clinical manifestations depending on the production of active peptide.

Methods:

Imaging modalities play a fundamental role in initial diagnosis as well as in staging and treatment monitoring of NENs, in particular they vastly enhance the understanding of the physiopathology and diagnosis of NENs through the use of somatostatin analogue tracers labeled with appropriate radioisotopes. Additionally, the use of somatostatin analogues provides the ability to in-vivo measure the expression of somatostatin receptors on NEN cells, a process that might have important therapeutic implications.

Results:

A large body of evidences showed improved accuracy of molecular imaging based on PET/CT radiotracer with SST analogues (e.g. [68Ga]-DOTA peptide) for the detection of NEN lesions in comparison to morphological imaging modalities. So far, the role of imaging technologies in assessing treatment response is still under debate.

Conclusion:

This review offers the systems of classification and grading of NENs and summarizes the more useful recommendations based on data recently published for the management of patients with NENs, with special focus on the role of imaging modalities based on SST targeting with PET / CT radiotracers.

Mixed Neuroendocrine Carcinoma and Squamous Cell Carcinoma of the Colon: Case Report and Literature Review

Neuroendocrine carcinoma (NEC) of the colon is very rare, and squamous cell carcinoma (SCC) of colon cancer is rare. We recently treated a patient with both NEC and SCC that initially presented as multiple unresectable liver and lung metastases. A 68-year-old Japanese man was referred to our hospital because of diarrhea with descending colon cancer obstruction. He underwent a left colectomy. Based on immunohistochemistry results, we diagnosed mixed NEC and SCC, the primary lesion location of which was probably the lung in the final pathologic examination. He began systemic palliative chemotherapy with CDDP and CPT-11. After 3 months of treatment, shown the progressive disease, we started CDDP and VP-16. The patient was not eligible for additional chemotherapy after 2 months.

Octreotide long-acting repeatable in the treatment of neuroendocrine tumors: patient selection and perspectives

Over the past three decades, the incidence and prevalence of neuroendocrine tumors have gradually increased. Due to the slow-growing nature of these tumors, most cases are diagnosed at advanced stages. Prognosis and survival are associated with location of primary lesion, biochemical functional status, differentiation, initial staging, and response to therapy. Octreotide, the first synthetic somatostatin analog, was initially used for the management of gastrointestinal symptoms associated with functional carcinoid tumors. Its commercial development over time led to long-acting repeatable octreotide acetate, a long-acting version that provided greater administration convenience. Recent research demonstrates that octreotide’s efficacy has evolved beyond symptomatic management to targeted therapy with antitumoral effects. This review examines the history and development of octreotide, provides a synopsis on the classification, grading, and staging of neuroendocrine tumors, and reviews the evidence of long-acting repeatable octreotide acetate as monotherapy and in combination with other treatment modalities in the management of non-pituitary neuroendocrine tumors with special attention to recent high-quality Phase III trials.

Predictive Factors for Lymph Node Metastasis and Prognostic Factors for Survival in Rectal Neuroendocrine Tumors

INTRODUCTION

Neuroendocrine tumors have malignant potential, and lymph node metastasis can occur. This study aimed to identify predictive factors of lymph node metastasis and prognostic factors for survival in rectal neuroendocrine tumors.

METHODS

Sixty-four patients underwent endoscopic or surgical treatment for rectal NET. The data on these patients were collected in our database prospectively and reviewed retrospectively.

RESULTS

Transanal excision was performed in 28 (43.8%) patients, endoscopic mucosal resection or submucosal dissection was performed in 15 (23.4%) patients, and radical resection was performed in 21 (31.8%) patients. Lymph node and distant metastasis was present in 16 (25.0%) and fir (7.8%) patients. The significant risk factors for lymph node metastasis identified in the multivariable analyses were tumor size (≥ 2 cm, p = 0.003) and tumor grade (G2, p < 0.001; G3, p = 0.008). In patients with a tumor smaller than 2 cm, the risk factors for lymph node metastasis included the tumor grade, mitosis count, and Ki-67 index. The median follow-up period was 30.0 months, and recurrence developed in four (6.8%) patients. The significant prognostic factors for survival included tumor size, T stage, lymph node metastasis, and tumor grade.

CONCLUSION

Tumor grade combined with tumor size is an important predictive factor for lymph node metastasis and could serve as a prognostic factor for survival outcomes.

Patient with typical carcinoid initially diagnosed as high-grade neuroendocrine carcinoma

We report the case of a patient initially diagnosed with a high-grade neuroendocrine carcinoma, which 5 years later was determined to have a low-grade typical carcinoid. The patient received radiotherapy and numerous chemotherapy regimens for treatment of a high-grade metastatic mixed large and small cell neuroendocrine carcinoma, without a significant response to any treatment. Subsequent imaging revealed widely metastatic disease and computed tomography-guided biopsy demonstrated a carcinoid tumor with no necrosis. The patient was started on temozolomide + capecitabine, long-acting octreotide and denosumab, with everolimus planned upon disease progression. Findings from this case study highlight the importance of accurate histopathologic classification of thoracic neuroendocrine tumors at diagnosis, to avoid the unnecessary administration of aggressive chemotherapy to patients with low-grade tumors.

Grade Assignment by Ki-67 Proliferative Index, Mitotic Count, and Phosphohistone H3 Count in Surgically Resected Gastrointestinal and Pancreatic Neuroendocrine Tumors

OBJECTIVES

The aim of this study was to evaluate the concordance in grade assignment for gastroenteropancreatic neuroendocrine tumors using mitotic count (MC), Ki-67 proliferative index (KPI), and phosphohistone H3 count (PHH3C).

METHODS

Resected gastroenteropancreatic neuroendocrine tumors were graded based on MC, KPI, and PHH3C. Concordance was determined using a weighted κ statistic. Median survival across each grade category was determined using Kaplan-Meier methods.

RESULTS

Of the 110 patients, the majority had gastrointestinal primaries and grade 1 or 2 tumors. Rates of discordance in grade assignment were 29% of cases for KPI versus MC (κW = 0.26), 32% for PHH3C versus MC (κW = 0.34), and 32% for PHH3C versus KPI (κW = 0.37). There was fair agreement between grading by KPI and MC. Relative to grade by KPI and MC, PHH3C tended to upgrade tumors. The proportion alive at 3 and 5 years was not significantly different for patients with grade 1 versus grade 2 tumors.

CONCLUSIONS

The concordance between KPI and MC was fair. Phosphohistone H3 count tended to upgrade tumors using the cutoffs established by MC. Grade 1 and grade 2 tumors were associated with similar survival regardless of grading method. The overall relevance of the current cutoff values used in grading neuroendocrine tumors may need to be revisited.

Fine needle aspiration cytology of hepatic metastases of neuroendocrine tumors: A 20-year retrospective, single institutional study

BACKGROUND

Fine needle aspiration (FNA) is considered an excellent technique for documenting metastatic neuroendocrine tumors (NETs). This study aims to evaluate the accuracy of FNA in diagnosing metastatic NETs to the liver and determining the grade and origin of these metastases.

METHODS

Our laboratory information system was searched from 1997 to 2016 to identify all cases of metastatic NETs to the liver that were sampled by FNA. The cytopathology and surgical pathology reports as well as the patients' electronic medical records were reviewed. The cytohistologic type and grade of the metastatic NETs, as well as the site of the patient's primary were recorded.

RESULTS

High-grade NETs, including small cell and poorly differentiated neuroendocrine carcinomas, constituted 62% (167/271) of the cases, while low-grade NETs, including well differentiated NET (grade1 and grade 2), pheochromocytomas, paragangliomas, and carcinoid tumors of lung, constituted 38% (104/271) of cases. The most common diagnosis was metastatic small cell carcinoma accounting for 45% (122/271) of cases. The most common primary sites were lung (44%; 119/271) followed by pancreas (19%; 51/271). The FNA diagnosis was confirmed by histopathology in 121 cases that had a concurrent biopsies or resection specimens.

CONCLUSIONS

FNA is an accurate method for diagnosing metastatic NETs to the liver. There were significantly more high-grade (62%) than low-grade (38%) metastatic NETs to the liver. In our practice, lung (44%) and pancreas (19%) were the most common primary sites of metastatic NETs involving the liver. In 16% of the cases, a primary site could not be established.

Sarcoidosis mimicking metastatic progression of pancreatic neuroendocrine tumor: A case report

RATIONALE

Pancreatic neuroendocrine tumors (PNETs) account for less than 5% of all pancreatic tumors. PNETs develop from pancreatic endocrine islet cells and have a variable range of malignant potential. These neoplasms tend to have a slower growth rate than exocrine tumors and may remain undetectable for years. Achieving a correct diagnosis and staging is of key importance for the optimal management of the disease and requires experience with the disease, an accurate clinical status evaluation and a critical interpretation of the radiological findings derived from morphological and functional imaging techniques as well as an integrated multidisciplinary approach. The possibility that some clinical data and radiological findings encountered during the diagnostic and staging procedures may not be related to PNETs but to concomitant clinical conditions should always be taken into consideration. This is mandatory as an incorrect stadiation may lead to patients' mis-management.

PATIENT CONCERNS

We report the case of a 34-year-old female, with a past medical history of idiopathic acute pancreatitis, presenting with a severe upper abdominal pain, steady and radiating to the back.

DIAGNOSES

Initial investigations incidentally detected a nonfunctioning pancreatic neuroendocrine tumor (NF-PNET) of intermediate grade G2. Subsequent investigations aimed at determining a correct tumor staging showed a negative indium-111- OctreoScan but an increased 18F-labeled fluorodesossiglucose (18F-FDG) uptake in multiple bilateral nodules in the lungs and in 1 nodular lesion located in the right gluteal subcutaneous tissue. An early tumor progression of a G2 NF-PNET that had to be treated with chemotherapy was suspected.

INTERVENTIONS

The histological examination of the gluteal subcutaneous nodule showed noncaseating granulomas, disproving the initial clinical suspect and allowing the diagnosis of active sarcoidosis in the G2 NF-PNET patient.

LESSONS

A misdiagnosis and a consequent therapeutic mismanagement were avoided with the support of an integrated multidisciplinary team.

Synaptophysin-Ki67 double stain: a novel technique that improves interobserver agreement in the grading of well-differentiated gastrointestinal neuroendocrine tumors

A common problem in the assessment of Ki67 proliferative index in well-differentiated gastrointestinal neuroendocrine tumors is distinguishing tumor from non-tumor. This is because background stromal lymphocytes, entrapped non-neoplastic glands, and the delicate vascular network characteristic of neuroendocrine tumors frequently contain a subset of proliferating cells. Furthermore, in small biopsies, crush and cautery artifact can alter the morphologic appearance of tumor cells, making the Ki67 proliferative index more difficult to assess. To address these issues, we developed a synaptophysin-Ki67 double stain using a commercially available immunohistochemistry kit, allowing simultaneous visualization of tumor and proliferating nuclei. To test this method, three gastrointestinal pathologists individually graded 50 gastrointestinal neuroendocrine tumors first using synaptophysin-Ki67 double-stained slides and then, after a washout period, using Ki67-only stained slides (along with routine hematoxylin- and eosin-stained slides). Interobserver agreement on Ki67 proliferative index was moderate using the Ki67-only stained slides (intraclass correlation 0.51, 95% confidence interval: 0.35-0.66) and improved using the synaptophysin-Ki67 double stain (intraclass correlation 0.79, 95% confidence interval: 0.69-0.86). Similarly, interobserver agreement on tumor grade was fair with Ki67-only stained slides (κ=0.39, P<0.001) and improved with the double stain (κ=0.58, P<0.001). Analysis of individual pathologists' scores revealed that fewer total number of tumor cells counted correlated with higher grade designation and appeared to contribute to grade discordance. In tumors cited as particularly challenging to assess by the pathologists, three of four tumors were grade discordant with the Ki67-only stain, whereas all four tumors were grade concordant with the synaptophysin-Ki67 stain. The synaptophysin-Ki67 double stain is the first technique to address specifically the histomorphologic challenges of evaluating Ki67 proliferative index in well-differentiated gastrointestinal neuroendocrine tumors. Although further validation is needed, this study provides evidence that the synaptophysin-Ki67 double stain can improve interobserver agreement.

CXCR4/CXCL12/CXCR7 axis is functional in neuroendocrine tumors and signals on mTOR

Objective

To evaluate the possible crosstalk between C-X-C chemokine receptor 4 (CXCR4)/C-X-C motif chemokine 12 (CXCL12)/C-X-C chemokine receptor 7 (CXCR7) axis with the mammalian target of rapamycin (mTOR) pathway in neuroendocrine tumors (NETs).

Methods

Sixty-one human NETs were included into the study. CXCR4/CXCL12/CXCR7 axis and mTOR pathway were assessed by qRT-PCR and immunohistochemistry (IHC). The effect of mTOR inhibitor, RAD001, was evaluated on CXCR4 pathway through proliferation and p-Erk and p-AKT induction. Results: CXCR4/CXCL12/CXCR7 axis and p-mTOR were found to be active and correlated with grading, Ki67 index and tumor stage. mTOR pathway activation significantly correlated with poor prognosis. In human NET cells, CXCL12 induced mTOR signalling while AMD3100 (CXCR4-antagonist) impaired it. The mTOR-antagonist, RAD001, impaired the CXCL12-dependent induction of CXCR4 downstream effectors. Combination of AMD3100 and RAD001 potentiate cell growth inhibition.

Conclusions

CXCR4/CXCL12/CXCR7 axis is active in NETs and signals on mTOR. CXCR4 might be considered a prognostic factor in NETs. Combined treatment with AMD3100 and RAD001 may provide clinical benefits in NET patients with drug-resistant.

Guidelines for the management of neuroendocrine tumours by the Brazilian gastrointestinal tumour group

Neuroendocrine tumours are a heterogeneous group of diseases with a significant variety of diagnostic tests and treatment modalities. Guidelines were developed by North American and European groups to recommend their best management. However, local particularities and relativisms found worldwide led us to create Brazilian guidelines. Our consensus considered the best feasible strategies in an environment involving more limited resources. We believe that our recommendations may be extended to other countries with similar economic standards.

Small cell neuroendocrine carcinoma of the paranasal sinus with intraoral involvement: Report of a rare case and review of the literature

The diffuse neuroendocrine system continues to be an enigmatic topic of study in pathology due to its controversial embryologic origins, biology and a variety of tumors engendered. Originally thought to be localized to the classic neuroendocrine organs (pituitary, thyroid, pancreas and adrenal medulla), the neuroendocrine cells are now known to be distributed in every organ system of the body. A number of human diseases have been linked to aberrations in the functioning of the neuroendocrine cells. Neoplasms of the neuroendocrine system can thus occur in myriad primary sites and range in behavior from benign to lethal. Small cell neuroendocrine carcinoma (SNEC) is a high-grade neuroendocrine tumor, rarely presenting in the sinonasal region. This article reports a case of a 68-year-old male patient with primary paranasal SNEC showing intraoral involvement. The diagnosis is based on a thorough clinical, histopathological and immunohistochemical workup to differentiate it from the other small round blue cell tumors.

Small Cell Carcinoma of the Pancreas: A Surgical Disease

OBJECTIVES

Primary pancreatic small cell carcinomas (PSCCs) are rare, and benefits of surgery are unknown. Utilizing the National Cancer Data Base, surgical outcomes of PSCC were determined and compared with pancreatic ductal adenocarcinoma (PDAC).

METHODS

Patients with histologically confirmed PSCC (n = 541) and PDAC (n = 156,733) were identified from the National Cancer Data Base (1998-2011). Parametric comparisons of patient and outcomes data were made. Unadjusted Kaplan-Meier and Cox proportional hazards analyses were performed.

RESULTS

Primary pancreatic small cell carcinomas accounted for 0.2% of all pancreatic tumors. Demographics were similar to PDAC. A higher proportion of PSCC were metastatic at diagnosis (75.6% vs 53.6%, P < 0.001). In stage I/II, 45.6% of PDAC versus 21.8% of PSCC underwent surgery. Node status, lymphovascular invasion, margin negativity rates, and perioperative outcomes were similar. Median unadjusted overall survival was similar for resected PDAC and PSCC (16.9 vs 20.7 months; P = 0.337). On multivariable analysis within resectable PSCC (stages I-II), the greatest independent predictors of mortality were age 65 years or older (hazards ratio, 2.78; 95% confidence interval, 1.56-4.97; P = 0.00055) and nonreceipt of surgery (hazards ratio, 2.66; 95% confidence interval, 1.24-5.71; P = 0.01).

CONCLUSIONS

Although PSCC commonly presents with distant disease, patients with anatomically resectable tumors derive similar benefit from aggressive surgical intervention as PDAC and should be counseled accordingly.

Ki67 Scoring in Pancreatic Neuroendocrine Tumors By a New Method

Ki67 scoring is required for the grading of pancreatic neuroendocrine tumors. Ongoing debate exists about the best scoring method in terms of accuracy and practicality. Manual counting of cells in camera-captured/printed images is a widely used and accepted method and considered the most reliable one among the manual methods. It requires counting 500 to 2000 cells to determine the Ki67 score accurately and it is time and energy consuming. We investigated the possibility of achieving the same results by counting only a particular fraction of tumor cells in a printed image in a series of 45 (24 grade 1 and 21 grade 2) pancreatic neuroendocrine tumors. After counting Ki67-positive tumor cells in the whole image, the tumor cells were counted within one-tenth of the same image with the aid of a previously prepared grid on an acetate sheet. The cell number obtained was multiplied by 10 to estimate the total cell count and the Ki67 score was calculated. The agreement between the results of the acetate grid and conventional whole-image counting method was assessed. Near-perfect agreement was achieved regarding the total cell count and Ki67 score. The agreement on tumor grade between the two methods was perfect. The time spent on the process was significantly less than that spent on the conventional method. Although it needs to be validated in a larger series, the acetate grid method might be considered an alternative method for Ki67 scoring in neuroendocrine tumors.

The Impact of Phosphohistone-H3-Assisted Mitotic Count and Ki67 Score in the Determination of Tumor Grade and Prediction of Distant Metastasis in Well-Differentiated Pancreatic Neuroendocrine Tumors

This study investigated the impact of phosphohistone-H3 (PHH3)-assisted mitotic count by comparing its performance with conventional mitotic count and Ki67 score as well as the status of distant metastasis. A total of 43 surgically resected pancreatic neuroendocrine tumors (panNET) with complete follow-up information has been subjected to a standardized assessment with respect to mitotic count (both conventional and PHH3-assisted) and Ki67 score. Five participants assessed mitotic count and the time spent was recorded in both methods. All tumors were assigned to a G1 category of mitotic rate on conventional mitotic count that failed to identify three tumors with a G2 category of mitotic rate on PHH3. Near-perfect and fair agreements were achieved among observers when using PHH3 and conventional method, respectively. The mean time spent to determine mitotic count on PHH3-stained slides was significantly shorter (p < 0.001). The performance of PHH3-assisted mitotic grade category was significant as the three cases with a G2 mitotic category were associated with distant metastasis (p = 0.01). Despite its performance, the PHH3-assisted mitotic count downgraded 17 cases that were classified as G2 based on Ki67 scores in this series. The Ki67 grade category was either the same or higher than the mitotic grade category. Ten patients developed distant metastasis. Eleven tumors exhibited vascular invasion characterized by intravascular tumor cells admixed with thrombus. Our results indicate that PHH3-assisted mitotic count facilitates an accurate mitotic count with a perfect agreement among observers. The small size of this cohort is an important limitation of the current study, a G2 mitotic grade category based on PHH3 immunohistochemistry was one of the correlates of panNETs with distant metastasis. While the prognostic impact of PHH3-assisted mitotic count needs to be clarified in larger cohorts, Ki67 scores designated higher grade category in all cases; thus, it was the best determinant of the tumor grade. More importantly, the presence of vascular invasion along with the Ki67 grade category was found to be independent predictors of distant metastasis.

Primary intracranial neuroendocrine tumor with ectopic adrenocorticotropic hormone syndrome: A rare and complicated case report and literature review

Neuroendocrine tumors (NETs) and ectopic adrenocorticotropic hormone (ACTH) syndrome are frequent in adult patients. However, primary intracranial NETs, exhibiting immunonegativity for ACTH, high serum ACTH level and treated with anterior skull base reconstruction, are rare and complicated. We herein present a case of a primary intracranial NET immunonegative for ACTH, resulting in ectopic ACTH syndrome. A 40-year-old woman presented with intermittent rhinorrhea, rapid weight gain, polydipsia, polyuria, hypertension, dimness, bilateral exophthalmus, diminution of vision in the left eye and pigmentation of the skin of the face and trunk. Computed tomography (CT) and magnetic resonance imaging scans revealed a sizeable enhancing tumor in the anterior cranial fossa, which infiltrated the sphenoid and ethmoid sinuses bilaterally, the left maxillary sinus and the nasal cavity. Abdominal CT scans revealed bilateral adrenal hyperplasia. The biochemical findings included hypokalemia and high glucose, cortisol, plasma ACTH, 24-h urinary free cortisol and testosterone levels. The neoplasm was exposed through a right frontal craniotomy, while anterior skull base reconstruction was performed during surgery. The intracranial surgery achieved gross removal of the tumor; however, part of the tumor remained in the nasal cavity. Histopathological examination of the surgical specimen confirmed the diagnosis of a low-grade small-cell NET, exhibiting immunonegativity for ACTH. A postoperative abdominal CT scan demonstrated bilateral regression of the adrenal gland hyperplasia and the serum ACTH level returned to normal after 16 days. To the best of our knowledge, there are no previous reports of primary intracranial NETs, immunohistochemically negative for ACTH, resulting in ectopic ACTH syndrome.

Primary intracranial neuroendocrine tumor: two case reports

BACKGROUND

Neuroendocrine tumor originates from the diffuse neuroendocrine system. Intracranial originating is lower to 0.74 %.

CASE PRESENTATION

We present two cases of primary intracranial neuroendocrine tumor A 39-year-old woman was admitted with headache, fever, polydipsia and polyuria. Biochemical and endocrinological results showed hyponatremia, hypothyroidism and hypopituitarism. MRI scans demonstrated an obviouslyenhancing lesion in seller and superseller area. Then a gross removal of tumor was achieved during the single nostril transsphenoidal approach surgery. Pathological diagnosis was high-grade small-cell neuroendocrine tumor. A 40-year-old woman presented with multiple symptoms and neurological deficit. Neuroimaging results demonstrated a huge obviously-enhancing tumor in anterior cranial fossa. Biochemical and hormone findings revealed hypokalemia, high glucose and hypercortisolemia. The intracranial surgery achieved a gross removal through a right frontal craniotomy. Pathological diagnosis was low-grade small-cell neuroendocrine tumor with immuno-negativity for ACTH.

CONCLUSION

The mechanism, diagnosis, and treatment of neuroendocrine tumor are still challenging.

Benign and malignant tumors of the rectum and perirectal region

Although most rectal masses are histologically characterized as adenocarcinomas, the rectum and perirectal region can be affected by a wide variety of tumors and tumor-like conditions that can mimic the symptoms caused by rectal adenocarcinoma, including mucosal or submucosal rectal tumors such as lymphoma, gastrointestinal stromal tumor, leiomyosarcoma, neuroendocrine tumor, hemangioma, and melanoma, as well as tumors of the perirectal region such as developmental cyst, neurogenic tumor, osseous tumor, and other miscellaneous conditions. As a group, tumors of the rectum are considerably different from the group of tumors that arise in the perirectal region: they are most often neoplastic, symptomatic, and malignant, whereas tumors arising in the perirectal region are most commonly congenital, asymptomatic, and benign. Proctoscopy with biopsy is the most important method for the diagnosis of rectal tumors, but this procedure cannot determine the precise intramural extension of a rectal tumor and cannot accurately distinguish submucosal and intramural tumors from extramural tumors. Cross-sectional imaging, especially transrectal ultrasound and magnetic resonance imaging, allows evaluation of the entire bowel wall thickness and the perirectal tissues, helping further characterize these tumors. Recognition of the existence of these masses and their key clinical and imaging features is crucial for clinicians to accurately diagnose and appropriately manage these conditions.

The spectrum of neuroendocrine tumors: histologic classification, unique features and areas of overlap

Neuroendocrine neoplasms are diverse in terms of sites of origin, functional status, and degrees of aggressiveness. This review will introduce some of the common features of neuroendocrine neoplasms and will explore the differences in pathology, classification, biology, and clinical management between tumors of different anatomic sites, specifically, the lung, pancreas, and prostate. Despite sharing neuroendocrine differentiation and histologic evidence of the neuroendocrine phenotype in most organs, well-differentiated neuroendocrine tumors (WD-NETs) and poorly differentiated neuroendocrine carcinomas (PD-NECs) are two very different families of neoplasms. WD-NETs (grade 1 and 2) are relatively indolent (with a natural history that can evolve over many years or decades), closely resemble non-neoplastic neuroendocrine cells, and demonstrate production of neurosecretory proteins, such as chromogranin A. They arise in the lungs and throughout the gastrointestinal tract and pancreas, but WD-NETs of the prostate gland are uncommon. Surgical resection is the mainstay of therapy, but treatment of unresectable disease depends on the site of origin. In contrast, PD-NECs (grade 3, small cell or large cell) of all sites often demonstrate alterations in P53 and Rb, exhibit an aggressive clinical course, and are treated with platinum-based chemotherapy. Only WD-NETs arise in patients with inherited neuroendocrine neoplasia syndromes (e.g., multiple endocrine neoplasia type 1), and some common genetic alterations are site-specific (e.g., TMPRSS2-ERG gene rearrangement in PD-NECs arising in the prostate gland). Advances in our understanding of the molecular basis of NETs should lead to new diagnostic and therapeutic strategies and is an area of active investigation.

Genomic Characterization of Poorly Differentiated Neuroendocrine Carcinoma in a Pediatric Patient

Primary neuroendocrine carcinomas (NEC) are rare tumors in children and young adults, resulting in a lack of standardized treatment approach. To refine the molecular taxonomy of these rare tumors, we performed whole exome sequencing in a pediatric patient with mediastinal NEC. We identified a somatic mutation in HRAS gene and LOH regions in NF2, MYO18B, and RUX3 genes. In addition, a germline heterozygous somatic variant in BRCA2 with LOH at that same position in the tumor tissue was also found. Our data provide valuable insight into the genomic landscape of this tumor, prompting further investigation of therapeutic targets.

Efficacy and Safety of Carboplatin and Etoposide Combination Chemotherapy for Extrapulmonary Neuroendocrine Carcinoma: A Retrospective Case Series

Background: Neuroendocrine carcinoma (NEC) is a rare tumor type, and a standard therapy for NEC has not yet been established. From 2008 to 2013, carboplatin-etoposide combination therapy has been used to treat almost all NEC patients in our department, and the objective of the present study was to investigate the therapeutic effects of carboplatin-etoposide combination therapy in NEC. Methods: This retrospective study was conducted based on medical records from 2008 to 2013. Eligible patients had been pathologically diagnosed with NEC and had received a carboplatin-etoposide combination as first-line chemotherapy. Results: Nineteen patients were included in the study, and the overall response rate was 47.4%. The median overall survival was 12.7 months, and the median progression-free survival was 7.0 months. The median survival times were 10.8 and 8.9 months in NEC patients with primary sites in the gastrointestinal tract and hepatobiliary-pancreatic system, respectively. Median progression-free survival times were 5.0 and 3.1 months, respectively. The major toxicities were grade 3 and 4 leukopenia (73.7%), neutropenia (78.9%), anemia (31.6%), and thrombocytopenia (26.3%). Conclusions: Carboplatin-etoposide combination therapy for NEC may have comparable effectiveness and milder adverse events than cisplatin-etoposide combination therapy.

Pathologic Classification of Neuroendocrine Neoplasms

The pathologic classification of neuroendocrine neoplasms has evolved over the past decades, as new understanding of the biological behavior, histologic characteristics, and genetic features have emerged. Nonetheless, many aspects of the classification systems remain confusing or controversial. Despite these difficulties, much progress has been made in determining the features predicting behavior. Genetic findings have helped establish relationships among different types of neuroendocrine neoplasms and revealed potential therapeutic targets. This review summarizes the current approach to the diagnosis, classification, grading, and therapeutic stratification of neuroendocrine neoplasms, with a focus on those arising in the lung and thymus, pancreas, and intestines.

Cytology Specimen Management, Triage and Standardized Reporting of Fine Needle Aspiration Biopsies of the Pancreas

The recent advances in pancreas cytology specimen sampling methods have enabled a specific cytologic diagnosis in most cases. Proper triage and processing of the cytologic specimen is pivotal in making a diagnosis due to the need for ancillary testing in addition to cytological evaluation, which is especially true in the diagnosis of pancreatic cysts. Newly proposed terminology for pancreaticobiliary cytology offers a standardized language for reporting that aims to improve communication among patient caregivers and provide for increased flexibility in patient management. This review focuses on these updates in pancreas cytology for the optimal evaluation of solid and cystic lesions of the pancreas.

Calculation of the Ki67 index in pancreatic neuroendocrine tumors: a comparative analysis of four counting methodologies

Ki67 index is now an essential part of classification of pancreatic neuroendocrine tumors. However, its adaptation into daily practice has been fraught with challenges related to counting methodology. In this study, three reviewers used four counting methodologies to calculate Ki67 index in 68 well-differentiated pancreatic neuroendocrine tumors: (1) 'eye-ball' estimation, which has been advocated as reliable and is widely used; (2) automated counting by image analyzer; (3) manual eye-counting (eye under a microscope without a grid); and (4) manual count of camera-captured/printed image. Pearson's correlation (R) was used to measure pair-wise correlation among three reviewers using all four methodologies. Average level of agreement was calculated using mean of R values. The results showed that: (1) 'eye-balling' was least expensive and fastest (average time <1 min) but had poor reliability and reproducibility. (2) Automated count was the most expensive and least practical with major impact on turnaround time (limited by machine and personnel accessibility), and, more importantly, had inaccuracies in overcounting unwanted material. (3) Manual eye count had no additional cost, averaged 6 min, but proved impractical and poorly reproducible. (4) Camera-captured/printed image was most reliable, had highest reproducibility, but took longer than 'eye-balling'. In conclusion, based on its comparatively low cost/benefit ratio and reproducibility, camera-captured/printed image appears to be the most practical for calculating Ki67 index. Although automated counting is generally advertised as the gold standard for index calculation, in this study it was not as accurate or cost-effective as camera-captured/printed image and was highly operator-dependent. 'Eye-balling' produces highly inaccurate and unreliable results, and is not recommended for routine use.

Development of multifocal nodular lesions of a liver mimicking hepatic metastasis, following resection of an insulinoma in a child

Insulinoma, which arises from insulin-producing pancreatic beta cells, is a rare tumor in children. Only 5%-10% of insulinomas are malignant and undergo metastasis. We report a case of an 11-year-old girl who experienced hypoglycemia-related seizures induced by an insulinoma; after resection of the primary tumor, she developed hepatic focal nodular hyperplasia (FNH). Laboratory test results indicated marked hypoglycemia with hyperinsulinemia. Abdominal ultrasonography (US) and computed tomography results were normal; however, magnetic resonance imaging (MRI) showed a solid mass in the pancreatic tail. Therefore, laparoscopic distal pancreatectomy was performed. Two months after the surgery, an abdominal MRI revealed multiple nodular lesions in the liver. An US-guided liver biopsy was then performed, and histological examination revealed FNH without necrosis or mitotic activity. The patient has been free of hypoglycemia for 2 years, and recent MRI studies showed a decrease in the size of FNH lesions, without any evidence of metastasis. Even though no metastatic lesions are noted on imaging, close observation and follow-up imaging studies are required in a child with insulinoma that has malignant potential on histopathologic findings.

Somatostatin receptors in bronchopulmonary neuroendocrine neoplasms: new diagnostic, prognostic, and therapeutic markers

CONTEXT AND OBJECTIVES

Gastroenteropancreatic neuroendocrine neoplasms are known for their overexpression of somatostatin receptors (SSTRs), which provide the molecular basis for diagnostic and therapeutic interventions. In contrast, few data on the SSTR expression profile exist for bronchopulmonary neuroendocrine neoplasms (BP-NEN).

DESIGN AND SETTINGS

A total of 240 formalin-fixed, paraffin-embedded specimens from 26 typical carcinoid (TC), 30 atypical carcinoid (AC), and 34 small cell lung cancer (SCLC) patients were examined retrospectively by immunohistochemistry (IHC) using specific rabbit monoclonal antibodies and evaluated by the immunoreactive score. Adjacent slides from 20 samples of each tumor type were subjected to additional RT-quantitative PCR mRNA analysis.

RESULTS

With different expression patterns, SSTRs were present in most of the tumor sections, at both the protein and mRNA levels. The RT-quantitative PCR data correlated with the IHC scores. SSTR1 was detected in approximately 65% of the TC and AC, but hardly in the SCLC, whereas both SSTR2A and SSTR5 were present in approximately 45% of each entity. Furthermore, the SSTR1 expression level was positively correlated with patient survival.

CONCLUSIONS

Our results suggest that SSTRs can be used as novel diagnostic, prognostic, and therapeutic markers of BP-NEN. The differences in the SSTR expression profile between the three types of BP-NEN may help to set a diagnostic cutoff and predict patient prognosis. Similar to TC and AC, our results also revealed a previously unappreciated high level of SSTR2A expression in SCLC within a subgroup of patients. However, in most cases, pan-somatostatin analogs may represent an additional therapeutic option.

Neuroendocrine tumor in the mandible: a case report with imaging and histopathologic findings

Neuroendocrine tumors (NETs) arise from neuroendocrine cells and are mostly observed in the gastrointestinal tract, pancreas, and lungs. NETs in the oral and maxillofacial region are extremely rare. We report a case of a 59-year-old woman with an NET in the mandible. The patient did not show any symptoms except for remarkable swelling and bleeding. The lesion appeared as a radiolucent honeycomb abnormality with bone destruction on panoramic radiography. The histopathologic diagnosis following a biopsy was NET. Contrast-enhanced computed tomography (CT), 18F-fluorodeoxyglucose positron emission computed tomography (18F-FDG PET/CT), and adrenal scintigraphy-labeled meta-iodobenylguanidine were the modalities added to identify the primary site. Multiple lesions were confirmed in the gastrointestinal tract. Endoscopy was performed to identify the lesions, and several lesions were observed protruding from the mucous membranes. However, the endoscopy specimens did not yield an accurate diagnosis because adequate samples were not acquired. Blood and urine tests revealed no functional activity caused by the tumors. Although the origin was not histopathologically confirmed with endoscopy, this patient was situationally diagnosed with nonfunctional NET originating from the duodenum, as demonstrated by the metastases in the mandible.

Important of case-reports/series, in rare diseases: Using neuroendocrine tumors as an example

At present the publishing of case reports or case series involving small numbers of cases is controversial. While in the past they were commonly published by most journals, recently a number of prominent journals have either stopped publishing them or markedly reduced the numbers published. However, recently an increasing case is being made for their value and a number of new journals have been started devoted specifically to their publication. One of the arguments used for their value is their prominent role in rare diseases either in their recognition, full description or development of treatments. However this aspect has not been specifically studied. In this editorial this aspect is specifically examined using their role in neuroendocrine tumors as an example. Furthermore, the background of the controversy is briefly reviewed to better understand the context of this editorial.

[Gastroenteropancreatic neuroendocrine neoplasms. Role of biopsies]

Neuroendocrine neoplasms of the pancreas and the gastrointestinal tract are heterogeneous regarding etiology (e.g. sporadic or hereditary), histomorphology, hormone expression, hormone-related functional activity and especially the malignant potential. In neuroendocrine neoplasms the biopsy-based diagnosis plays an important role for the clinical management of patients. The diagnosis most importantly relies on the differentiation (e.g. organoid versus diffuse growth patterns) and the grading of tumors. The latter is based on the proliferation activity as determined by Ki-67 immunostaining and mitotic count and results in the current tumor classification into neuroendocrine tumors G1, neuroendocrine tumors G2 or neuroendocrine carcinomas G3. Occasionally, tumors may show mixed differentiation containing a non-neuroendocrine cancer component. The neuroendocrine markers synaptophysin and chromogranin A are recommended for the immunohistochemical confirmation of the diagnosis. Furthermore, biopsy material can be used to investigate the expression of therapy-related markers, such as somatostatin receptor-2A. Moreover, if needed, the expression of transcription factors and hormones can be determined to obtain information on the possible site of origin of metastatic neuroendocrine neoplasms or to determine the syndrome-inducing hormone in functionally active neuroendocrine neoplasms. Finally, using the stomach as an example, biopsies may also be successfully used to investigate neuroendocrine precursor lesions which may harbor prognostic significance.

Efficacy of somatostatin analogues in the treatment of neuroendocrine tumours based on the results of recent clinical trials

Due to their inhibitory effects on hormone secretion, somatostatin analogues are of pivotal importance in the symptomatic treatment of hormone-secreting neuroendocrine tumours. Although several earlier clinical observations supported the view that these biological agents are capable of inhibiting the growth of neuroendocrine tumours, the PROMID study published in 2009 was the first to confirm the inhibitory effect of octreotide on tumour growth and demonstrated the prolongation of progression free survival. These findings have been confirmed and extended by the most recent CLARINET trial with lanreotide published in 2014. Somatostatin analogues are capable of inhibiting tumour growth and stabilizing disease irrespective of the hormonal activity of the tumour and, therefore, their applicability is expected to be extended to the treatment of hormonally inactive neuroendocrine tumours, as well. Orv. Hetil., 2014, 155(48), 1908–1912.

Therapeutic strategies for neuroendocrine liver metastases

Patients who have neuroendocrine tumors frequently present with liver metastases. A wide panel of treatment options exists for these patients. Liver resection with curative intent achieves the best long-term results. Highly selected patients may be considered for liver transplantation. Substantial recurrence rates reported after surgical approaches call for neoadjuvant and adjuvant concepts. Liver-directed, locally ablative procedures are recommended for patients with limited, nonresectable tumor burden. Angiographic liver-directed techniques, such as transarterial embolization, transarterial chemoembolization, and selective internal radiotherapy, offer excellent palliation for patients with liver-predominant disease. Peptide receptor radionuclide therapy is a promising palliative procedure for patients with hepatic and/or extrahepatic metastases. The efficacy of these treatment options needs to be evaluated in randomized trials. Somatostatin analogues have demonstrated effectiveness not only for symptomatic relief in patients with secreting tumors but also for the control of proliferation in small intestinal neuroendocrine tumors and most recently also in those originating from the pancreas. Chemotherapy is an option mainly for those with pancreatic neuroendocrine tumors and high-grade tumors irrespective of the origin. Novel drugs targeting specific pathways within the tumor cell have produced improved progression-free survival compared with placebo in patients with pancreatic neuroendocrine tumors. Despite such a diverse armamentarium, there is uncertainty with regard to the optimal treatment regimens. Newly introduced molecular-based markers, along with the conduction of clinical trials comparing the efficacy of treatment modalities, offer a chance to move the treatment of neuroendocrine tumor disease toward personalized patient care. In this report, the authors review the approaches for treatment of neuroendocrine liver metastases, identify shortcomings, and anticipate future perspectives. Furthermore, clinical practice recommendations are provided for currently available treatment options. Although multiple modalities are available for the treatment of neuroendocrine liver metastases, optimal management is unclear. The current knowledge pertaining to these treatment options is analyzed.

Small bowel neuroendocrine tumors: the benefits of surgical intervention

Well-differentiated SI NETs are on the rise. Due in part to the indolent nature of these tumors, patients typically have a delay in diagnosis and present with metastatic disease. Surgeries for symptoms of either chronic intermittent small bowel obstruction and/or ischemia or from carcinoid syndrome have proven to provide excellent palliation. Most recently, several series have demonstrated an improved survival in those patients in whom the primary, locoregional disease has been resected. Several newer adjuncts have been developed to aid in the hepatic directed therapies such as ablation therapies, embolization and Y spheres. The ability to cytoreduce 70% or more of the hepatic tumor burden has been shown to not only to provide a biochemical and as such a clinical response, but also appears to prolong survival. All patients with SI NETs should be assessed in a multidisciplinary clinic and the first line of therapy should always be to assess surgical resectabilty.