Neuroendocrine Lesions Research Articles

Insulinoma-associated protein 1 (INSM1) immunohistochemical expression in normal, hyperplastic, and neoplastic canine neuroendocrine tissues.

Insulinoma-associated protein 1 (INSM1), a recently identified neuroendocrine marker, is a transcriptional regulator with highly conserved INSM1 homologues in various species. This study investigated the immunohistochemical reactivity of the INSM1 antibody in 20 normal canine neuroendocrine tissues from various anatomical locations, 87 hyperplastic or neoplastic tissues of neuroendocrine origin, and 62 non-neuroendocrine neoplasms and compared the results with those of chromogranin A and synaptophysin in neuroendocrine neoplasms. Western blot was performed on fresh canine pituitary glands and canine parathyroid glands to confirm the specificity of the anti-INSM1 antibody. The results showed that the anti-INSM1 antibody could detect nuclear expression in normal canine neuroendocrine tissues, except for the parathyroid glands. INSM1 was detectable in 79/87 (91%) of the hyperplastic and neoplastic neuroendocrine lesions, but all parathyroid carcinomas and parathyroid adenomas (three samples each) were negative for INSM1. In contrast, INSM1 was detected in only one of 62 (2%) non-neuroendocrine neoplasms. The overall percentage of neuroendocrine neoplasms that immunolabeled positively for all three markers was 89%. In addition, the nuclear expression of INSM1 was easier to interpret than that of chromogranin A or synaptophysin. These findings confirm that INSM1 is a useful immunohistochemical marker for diagnosing canine neuroendocrine neoplasms, except for parathyroid neoplasms, and should be considered as part of immunohistochemistry panels to improve diagnostic capability.

Spectra of well-differentiated neuroendocrine lesions in the extrahepatic biliary system: a case series.

Neuroendocrine tumours (NETs) occurring in the extrahepatic biliary system are exceedingly rare. While NETs typically manifest as mass lesions, the occurrence of microscopic neuroendocrine cell proliferation without a distinct mass remains undocumented at this location. This study aims to characterise the clinicopathological features of a series of well-differentiated neuroendocrine lesions involving the extrahepatic biliary tree, including mass forming NETs and microscopic non-mass-forming neuroendocrine cell proliferation, designated neuroendocrine cell micronests (NCMs). Surgical resections of NETs/NCMs involving the extrahepatic bile ducts and gallbladder were identified from electronic pathology databases among seven institutions spanning from January 2011 to September 2023. Clinical and histological findings were recorded. Ten patients (four female, six male: age range = 34-75 years) were included in the study. Histopathological examination revealed visible mass-forming lesions in four cases (1.6-14.0 cm in size), identified in the gallbladder (n = two) or extrahepatic bile duct (n = two), all diagnosed as well-differentiated NETs. The remaining six cases revealed incidental non-mass-forming NCMs in either the cystic duct (n = two), common bile duct (n = three) or gallbladder (n = one), ranging from < 0.1 to 0.4 cm; four were associated with biliary lithiasis. No evidence of metastasis or recurrence was seen in the follow-up period (range = 0.1-11.2 years). This study highlights the spectrum of extrahepatic biliary well-differentiated neuroendocrine lesions, ranging from incidental microscopic NCMs to grossly apparent mass-forming NETs, potentially requiring different clinical management. Noteworthy is the frequent association of incidental microscopic neuroendocrine cell proliferations with biliary lithiasis, indicating a potential neuroendocrine metaplastic pathogenesis that merits further exploration.

Ectopic Cushing's Syndrome in Pediatric Age

Cushing's syndrome due to ectopic ACTH secretion is a rare clinical condition resulting from a dysregulated ACTH secretion by neuroendocrine tumors. The overall incidence of endogenous Cushing's syndrome is 0.7-2.4 per million people annually, with children accounting for only 10% of new cases each year. When the patient first presented clinically, she was a 17-year-old girl who displayed psychiatric symptoms. Blood tests showed diabetes mellitus and hypokalemia. She had hypertension and vertebral collapses. The hormone assay showed hypercortisolism, and because of this, she began taking metyrapone. The results of the 68Ga-PET/DOTATOC and 18FDG-PET scans were negative. The clinical course was intermittent. After one year, a 68Ga-PET/DOTATOC showed a nodule in the thymic lodge. Despite the thymectomy, the hypercortisolism persisted. A subsequent 68Ga-PET/DOTATOC repeated three months after surgery revealed an uptake corresponding to the thymic lodge. She underwent another surgery, which is finally being resolved. ACTH levels were monitored before, during, and post-surgery. The laboratory provided the ACTH results promptly, and thoracic surgeons waited for hormonal results before concluding the procedure. The adopted strategy permitted us to monitor the surgery outcome. The heterogeneity of ectopic Cushing's syndrome makes diagnosis difficult. 68Ga-PET/DOTATOC proves to be a tracer with good sensitivity and specificity for the identification of ACTH-secreting neuroendocrine lesions. The short half-life of ACTH is found to be a strategy to monitor the complete surgical resection of the neuroendocrine lesion.

Revisiting Pulmonary Sclerosing Pneumocytoma.

Pulmonary sclerosing pneumocytoma (PSP) is a quite rare tumor outside Eastern countries. This rarity, together with a wide histological appearance, makes its correct identification a diagnostic challenge for pathologists under the microscope. Historically, PSP was considered a vascular-derived neoplasm (sclerosing hemangioma), but its immunohistochemical profile clearly supports its epithelial origin. No specific molecular fingerprint has been detected so far. This short narrative revisits the clinical, histological, immunohistochemical, and molecular aspects of this tumor, paying special attention to some controversial points still not well clarified, i.e., clinical aggressiveness and metastatic spread, multifocality, the supposed development of sarcomatoid change in a subset of cases, and tumor associations with lung adenocarcinoma and/or well-differentiated neuroendocrine hyperplasia/tumors. The specific diagnostic difficulties on fine-needle aspiration cytology/biopsy and perioperative frozen sections are also highlighted. Finally, a teaching case of tumor concurrence of lung adenocarcinoma, neuroendocrine lesions, and PSP, paradigmatic of tumor association in this context, is also presented.

Neuroendocrine Lesions Arising From Mediastinal Teratoma-A Case Report and Literature Review.

Background. Neuroendocrine lesions arising from mediastinal teratomas are rare tumors with only small number of patients reported in literature. The behavior of these lesions appears to be different from traditional neuroendocrine neoplasms. A comprehensive review will be valuable for histologic assessment and treatment planning for similar cases. Case presentation. We present an example of a 57-year-old man who presented with cough. Subsequent work-up revealed an anterior mediastinal mass of 2.1 cm on computed tomography. The patient underwent robot-assisted thoracoscopic thymectomy. Histological examination revealed a mature cystic teratoma with a neuroendocrine component consisting of clusters of tumor cells with round to oval nuclei and a "salt-and-pepper" chromatin pattern. The tumor cells were immunoreactive to cytokeratin, synaptophysin, chromogranin, and INSM1, with a Ki-67 proliferative index of 4%. A histological diagnosis was mature teratoma with well-differentiated low-grade neuroendocrine tumor (carcinoid) was made. The patient was well and without disease after complete surgical excision at 10 months. Literature review. Literature reviewed yielded 13 examples of neuroendocrine lesions arising from mediastinal teratomas. No disease-related mortality was reported, even in lesions with high-grade neuroendocrine, carcinomatous, or immature teratomatous components. Conclusions. Surgical removal is the mainstay of treatment of these lesions, and the presence of a neuroendocrine component does not appear to negatively affect prognosis.

Co-existing Neuroendocrine Tumors in the Ileum and Pancreas: A Clinico-Pathological Challenge.

Ileal (I) and pancreatic (Pan) neuroendocrine tumors (NETs) are among the most common digestive neuroendocrine neoplasms (NENs). Coexisting NETs at both sites are rare, and establishing the primary or metastatic nature of the two lesions may be crucial for the appropriate treatment. We reviewed all the clinical reports of patients with INETs or PanNETs, diagnosed and treated in our ENETS Center of Excellence between 2012 and 2022. We selected patients with a history of synchronous or metachronous neuroendocrine (NE) lesions at the ileum and pancreas. For those with available histological samples from both sites, an immunohistochemistry (IHC) analysis for CDX2, Islet1, and serotonin has been performed. We found seven patients with NET in both the ileum and pancreas. F to M ratio was 4:3, and the median age at first diagnosis was 54years (42-79). Five cases had synchronous lesions; in 2 cases, PanNETs were diagnosed respectively 8 and 56months, after INETs. In four patients, with available histological samples from both the sites, a pathologic review and the IHC analysis have been performed, identifying three different scenarios: (i) primary INET metastatic to the pancreas, (ii) primary PanNET metastatic to the ileum, and (iii) synchronous primary PanNET and INET. In our experience, coexisting ileal and pancreatic NENs are rare occurrences. A multidisciplinary evaluation case-by-case and, whenever feasible, a comprehensive histopathological examination are needed to distinguish between metastatic and primary disease, in order to properly treat the patient.

Pancreatic neuroendocrine tumours: a comparison of cytological classification systems

AimsCytological classification systems provide a standardised interpretation framework for reporting cytological specimens. Three well-known classification systems can be applied when reporting pancreatic cytology. This study aimed to compare the accuracy...

An audit of metastatic tumors to the liver highlighting the spectrum of differential diagnosis: A retrospective study from a tertiary cancer center in North India

ABSTRACT Background: Space-occupying lesions of the liver can broadly be divided into benign and malignant and further as primary and metastatic lesions. Among the malignant lesions of the liver, metastatic lesions of unknown primary origin present as one of the most common clinical dilemmas. Objectives: The primary objective was to study the histomorphological and immunohistochemical profiles of the secondaries to the liver. The secondary objective was to outline an approach toward an accurate diagnosis of the primary site and exclusion of the close differentials, especially in the case of round-cell tumors and spindle cell lesions. Materials and Methods: This retrospective cross-sectional study was conducted from May 2018 to September 2020 at the Department of Pathology, Homi Bhabha Cancer Hospital and Mahamana Pandit Madan Mohan Malaviya Cancer Center, Varanasi, Uttar Pradesh, India. All patients diagnosed with metastatic liver lesions were studied. The cases were reviewed for histomorphological and immunohistochemical findings, and the data were analyzed using Microsoft Excel. Results: A total of 452 cases were studied, and the mean age was 54.8 ± 13.5 (standard deviation) years with the age ranging from 7 months to 88 years (median, 56; interquartile range, 46-65 years) with female (n = 243, 53.8%) predominance. Adenocarcinomas (n = 302, 66.8%), followed by neuroendocrine lesions (n = 63, 13.9%), were the most common histology, while melanoma (n = 2, 0.4%) was the least common. The common sites of the primary were pancreaticobiliary (n = 231, 51.1%), lung (n = 58, 12.8%), breast (n = 31, 6.9%), and colorectal (n = 20, 4.4%). Less frequent lesions involving the liver, such as spindle cell lesions, lymphomas, melanomas, and germ cell tumors, were also noted. Conclusions: The liver is one of the most common sites of metastasis from various organs. Adenocarcinoma is the most common tumor, amid which metastasis from the pancreaticobiliary tract is the most common site of primary. Hence, a stepwise approach of immunohistochemistry in conjunction with clinicoradiological assessment is necessary for an apt diagnosis and treatment.

The lesion detection rate of Ga-68 DOTATATE PET/MR in multiple endocrine neoplasia type 1.

The purpose of the study was to determine the usefulness of Ga-68 DOTATATE PET/MR in the identification of tumours in individuals with multiple endocrine neoplasia type 1 (MEN1). In this retrospective investigation, five individuals who had tested positive for a hereditary MEN1 variant underwent Ga-68 DOTATATE PET/MR between May 2020 and January 2023. Several types of tumours associated with MEN1 were studied. MEN1-related tumours included pituitary, parathyroid, gastroenteropancreatic, and adrenal. The rates of lesion identification between MRI, Ga-68 DOTATATE PET, and Ga-68 DOTATATE PET/MRI were examined. The maximum and mean standard uptake values (SUVmax and SUVmean) were evaluated in carefully delineated volumes of interest (VOI) for the relevant tumours. Of the 24 primary lesions, 14 were identified by Ga-68 DOTATATE PET, 18 by MRI, and 20 by Ga-68 DOTATATE PET/MRI. Two pituitary tumours were detected by all three techniques. All parathyroid tumours that were not detected by Ga-68 DOTATATE PET and MRI were found by Tc-99m MIBI SPECT/CT or/and EUS. Ga-68 DOTATATE PET/MR detected more gastroenteropancreatic lesions. All adrenal tumours not identified by Ga-68 DOTATATE PET were found by MRI or CT. The median SUVmax for lesions identified on Ga-68 DOTATATE PET/MRI was 18.4 (range, 3.8-85.2), and the median SUVmean was 12.0 (range, 2.3-49.8). The combination of Ga-68 DOTATATE PET and MRI demonstrated a higher detection rate and may be more useful in the work-up of MEN1 providing a panoramic view of MEN1-related lesions. To increase the identification of MEN1-associated neuroendocrine lesions in the parathyroid gland, approaches other than Ga-68 DOTATATE PET/MRI should be used.

Liver Imaging in Gastroenteropancreatic Neuroendocrine Neoplasms.

The incidence of neuroendocrine neoplasms (NENs) has gradually increased over the past few decades with the majority of patients presenting with metastases on initial presentation. The liver is the most common site of initial metastatic disease, and the presence of liver metastasis is an independent prognostic factor associated with a negative outcome. Because NENs are heterogenous neoplasms with variable differentiation, grading, and risk of grade transformation over time, accurate diagnosis and management of neuroendocrine liver lesions are both important and challenging. This is particularly so with the multiple liver-directed treatment options available. In this review article, we discuss the diagnosis, treatment, and response evaluation of NEN liver metastases.

Primary Well-Differentiated Neuroendocrine Tumor/Carcinoid of the Prostate: Case Report and Review of Literature.

Primary well-differentiated neuroendocrine tumor (WDNT)/carcinoid of the genitourinary tract is rare. Many WDNT reported in the prostate gland have been seen in close association with conventional prostatic adenocarcinoma and/or label for prostate-specific immunohistochemical markers and are best considered prostatic adenocarcinomas with "carcinoid-like" features. We present a case of primary WDNT/carcinoid incidentally detected in a 67-year-old man who underwent radical prostatectomy for Grade group 2 prostatic adenocarcinoma. Morphologically, the neuroendocrine (NE) lesion appeared distinct from the prostatic adenocarcinoma, labeled for NE markers, was negative for prostatic markers (NKX3.1, PSA, and ERG), and showed an overall low Ki-67 proliferation index (<1%). Follow-up was uneventful with no evidence of residual disease or metastasis.

Comparison between findings of gallium-68 Dota PET-CT and contrast enhanced CT scan in neuroendocrine tumors.

Objective: To compare the efficiency of contrast enhanced CT-SCAN and Gallium 68-DOTA PET CT for the detection of neuroendocrine lesions. Study Design: Cross Sectional and Analytical study. Setting: INMOL (Institute of Nuclear Medicine and Oncology Lahore). Period: February 2020 to December 2020. Material &amp; Methods: Total of 70 patients between 18-68 year of age coming to Nuclear Medicine department of INMOL (Institute of Nuclear Medicine &amp; Oncology Lahore) were included in the study convenient sampling technique were used to collect the data. Results: 70 patients were selected who had malignant type of tumor (mass forming or metastatic) patients, 29(41%) were diagnosed with Pancreatic Tumors, 12 (17%) were diagnosed with Metastatic Tumors, 10 (14%) were diagnosed with Mesenteric Tumors, 7 (10%) were diagnosed with Renal Tumors, 7 (10 %) were diagnosed with Liver Tumors, 3 (4%) were diagnosed with Thyroid Tumors, 1(1.4 %) was Breast Tumor and 1(1.4%) was mediastinal Tumor. In CT-Scan out of 70 patients 42(60%) patients were diagnosed with tumor while 28(40%) patients were normal, meanwhile in PET CT, out of 70 patients 55(79%) patients were diagnosed with tumor while 15(21%) patients were normal. Out of 70 patients PET CT was able to identify all 55/55 tumor patients correctly while CT visualized 42 patients correctly but omitting I 3 patients, causing false negative diagnosis. PET CT has sensitivity and Specificity of 100% &amp; 99.9% respectively whereas CT had sensitivity &amp; Specificity of 76.8 % and 51.8% respectively. Conclusion: In contrast with international studies PET CT have better diagnostic finding for evaluation and follow up of Neuroendocrine tumors as compared to contrast enhanced CT Scan. We can say PET CT is a good and better modality other then any contrast enhanced modality like contrast enhanced CT scan for the evaluation of neuroendocrine tumors.

Urothelial Rests, Incidental Finding in a Patient with Acute Appendicitis: A Case Report and Literature Review

Background Urothelial rests, also known as Walthard rests, are benign nests of epithelial cells that most often are found in the female gynecologic tract. Only four of these urothelial rests have been described in the appendix. Case report: A 10-year-old female underwent an appendectomy for appendicitis. Histologically, there was acute appendicitis, and an incidental urothelial rest was identified, confirmed by immunostains positive for p63, CK7, and negative for synaptophysin. CD34 highlighted a rim of endothelial cells. Conclusion: Urothelial rests, which often appear in the female gynecologic tract, can occur in other sites such as the appendix. These benign lesions require differentiation from neuroendocrine lesions. The rim of endothelial cells in our report supports a vascular migrational origin.

Discordant Uptake Between Diagnostic 68Ga-HA-DOTATATE PET/CT and Posttherapy 177Lu-HA-DOTATATE SPECT/CT in Patients With Neuroendocrine Tumors.

Patients with unresectable or metastasized neuroendocrine tumors are assumed eligible for PRRT (peptide receptor radionuclide therapy) with 177Lu-HA-DOTATATE if tumor uptake on somatostatin receptor imaging is higher than normal liver tissue. In our clinic, 2 patients presented with sufficient uptake of 68Ga-HA-DOTATATE in most metastases but with limited uptake in liver lesions. Posttherapy 177Lu imaging, however, showed good uptake in all neuroendocrine tumor lesions, including all liver metastases. Therefore, the presence of liver metastases in which the uptake of 68Ga-HA-DOTATATE is not or only slightly higher than in surrounding normal liver tissue should not be an absolute contraindication for PRRT.

Lung cancer mimickers - a case series of seven patients and review of the literature.

Background: Lung is the third most frequent identified site of malignancy and lung cancer is the most lethal type of cancer in the world. Several benign lung diseases or proliferations may mimic lung carcinoma in its clinical, pathological, and radiological presentation, which makes the differential diagnosis life changing. This case series was designed to describe the main diagnosis encountered in a multidisciplinary emergency hospital during the last years in Romania. Results: The most challenging cases encountered during the recent years were those of lung hamartoma associated with eosinophilic pneumonia because of the multicentricity of the disease and the suspicion for metastasis in the clinical setting, pulmonary aspergillosis that presented as a cystic lesion with a 9 mm mural nodule, actinomycosis discovered as firm nodule showing aspects of false pleural invasion, cryptococcosis – a hilar mass for which a pneumectomy was prepared, pulmonary parasitosis that presented as a nodule with irregular borders, causing pleural retraction, one case of inflammatory myofibroblastic tumor of the lung, one case of tumorlet type neuroendocrine lesion in a patient with history of melanoma and renal oncocytoma, admitted under the suspicion of lung metastasis. Conclusions: These are some of the main mimickers of primary or secondary lung cancers and one must be aware of these similitudes to avoid higher cost procedures, psychological stress for the patient and higher mortality.

Neuroendocrine Tumors of the Thyroid and Their Mimics.

This paper will review neuroendocrine lesions of the thyroid and the differential diagnosis with the most significant such tumor of the thyroid, that is, medullary thyroid carcinoma. A brief overview of the understanding of this tumor's identification as a lesion of C cells and its familial and syndromic associations will be presented. Then, a discussion of the various mimics of medullary carcinoma will be given with an approach to the types of tests that can be done to arrive at a correct diagnostic conclusion. This review will focus on practical "tips" for the practicing pathologist.

Clinical impact of Ga68-DOTATOC PET/CT on neuroendocrine tumors. A preliminary experience

Ga-68-DOTATOC PET/CT is a recently introduced imaging technique for the diagnosis and follow-up of neuroendocrine tumors.A prospective observational study was conducted in seven patients who underwent a Ga-68-DOTATOC PET/CT study. They were suspected of active neuroendocrine tumor lesions, either on initial diagnosis or as a possible recurrence and/or progression of already known tumors. The results of prior imaging studies (MRI, thoracoabdominal CT scan, octreotide…), had been negative or inconclusive.All positive Ga-68-DOTATOC PETs were true positives, confirmed by pathological examination. There were no false positive results. Only one false negative result was found.Ga-68-DOTATOC PET/CC is more sensitive and specific for the detection of primary neuroendocrine tumor lesions, allows for a more complete extension study, and detects recurrences in earlier stages, conditioning changes in staging and surgical treatment. It provides additional information on somatostatin receptor overexpression, which is essential for the indication of PRRT (peptide receptor radionuclide therapy) with Lu177 dotatate.

Development and Validation of Diffuse Idiopathic Pulmonary Neuroendocrine Hyperplasia Diagnostic Criteria

IntroductionDiffuse idiopathic pulmonary neuroendocrine hyperplasia (DIPNECH) is a rare condition that is likely underdiagnosed owing to the lack of established and validated diagnostic criteria. These clinical guidelines are empirical and created on the basis of a limited number of studies. This study was designed to validate the existing criteria and to identify new clinical parameters that can accurately diagnose DIPNECH. MethodsPatients with DIPNECH were identified from a cohort that underwent surgical lung resection for pulmonary carcinoids. The study cohort included a total of 105 consecutive cases with neuroendocrine lesions. Initial diagnostic predictors of DIPNECH were selected from the literature. We employed univariate and multivariate models to evaluate the association of clinical, pathologic, radiologic variables with the likelihood of DIPNECH. ResultsUnivariate analysis identified age, sex, chronic obstructive pulmonary disease diagnosis, obstructive abnormalities, pulmonary nodules, mosaicism, absolute numbers of pulmonary neuroendocrine lesions (PNELs), and the number of tumorlets as significant DIPNECH predictors (for p < 0.05). After adjustment for sampling variations, the ratio of the total number of PNELs to the number of bronchioles was found to be considerably higher in DIPNECH category. Multivariate analysis identified the total number of PNELs and multiple pulmonary nodules (>10) as independent predictors of DIPNECH. The performance of our criteria revealed an accuracy of 76% in detecting DIPNECH cases. ConclusionsWe proposed a set of diagnostic criteria for DIPNECH on the basis of an expert-panel approach integrating pathological features, radiology, and clinical data. Our findings will help identify DIPNECH patients, without a pathological confirmation of a neuroendocrine lesion. Before the implementation of these criteria in clinical practice, they require further validation in multi-institutional cohorts.

Impacto clínico del PET/TC Ga68-DOTATOC en tumores de origen neuroendocrino. Experiencia preliminar

Ga-68-DOTATOC PET/CT is a recently introduced imaging technique for the diagnosis and follow-up of neuroendocrine tumors.A prospective observational study was conducted in seven patients who underwent a Ga-68-DOTATOC PET/CT study. They were suspected of active neuroendocrine tumor lesions, either on initial diagnosis or as a possible recurrence and/or progression of already known tumors. The results of prior imaging studies (MRI, thoracoabdominal CT scan, octreotide...), had been negative or inconclusive.All positive Ga-68-DOTATOC PETs were true positives, confirmed by pathological examination. There were no false positive results. Only one false negative result was found.Ga-68-DOTATOC PET/CC is more sensitive and specific for the detection of primary neuroendocrine tumor lesions, allows for a more complete extension study, and detects recurrences in earlier stages, conditioning changes in staging and surgical treatment. It provides additional information on somatostatin receptor overexpression, which is essential for the indication of PRRT (peptide receptor radionuclide therapy) with Lu177 dotatate.

Pancreatic grade 3 neuroendocrine tumors behave similarly to neuroendocrine carcinomas following resection: a multi-center, international appraisal of the WHO 2010 and WHO 2017 staging schema for pancreatic neuroendocrine lesions

BackgroundIn 2017, the WHO updated their 2010 classification of pancreatic neuroendocrine tumors, introducing a well-differentiated, highly proliferative grade 3 tumor, distinct from neuroendocrine carcinomas. The aim of this study was to investigate the clinical significance of this update in a large cohort of resected tumors. MethodsUsing a multicenter, international dataset of patients with pancreatic neuroendocrine lesions, patients were classified both according to the WHO 2010 and 2017 schema. Multivariable survival analyses were performed, and the models were evaluated for discrimination ability and goodness of fit. ResultsExcluding patients with a known germline MEN1 mutation and incomplete data, 544 patients were analyzed. The performance of the WHO 2010 and 2017 models was similar, however surgically resected grade 3 tumors behaved very similarly to neuroendocrine carcinomas. ConclusionThe addition of a grade 3 NET classification may be of limited utility in surgically resected patients, as these lesions have similar postoperative survival compared to carcinomas. While the addition may allow for a more granular evaluation of novel treatment strategies, surgical intervention for high grade tumors should be considered judiciously.