Imaging features of carcinoid tumors of the gastrointestinal tract. AJR Am J Roentgenol. 2013;201:773-786. [PMID: 24059366 DOI: 10.2214/ajr.12.9758]

Imaging Update for Hereditary Abdominopelvic Neuroendocrine Neoplasms

ABSTRACT

Neuroendocrine neoplasms have shown a linear increase in incidence and prevalence in recent decades, primarily due to improved cross-sectional imaging, expanded use of endoscopic procedures, and advanced genetic analysis. However, diagnosis of hereditary neuroendocrine tumors is still challenging because of heterogeneity in their presentation, the variety of tumor locations, and multiple associated syndromes. Radiologists should be familiar with the spectrum of these tumors and associated hereditary syndromes. Furthermore, as the assessment of multiple tumor elements such as morphology, biochemical markers, and presence of metastatic disease are essential for the treatment plan, conventional anatomic and functional imaging methods are fundamental in managing and surveilling these cases. Our article illustrates the role of different cross-sectional imaging modalities in diagnosing and managing various hereditary abdominopelvic neuroendocrine tumors.

21 years of evolution of primary hepatic neuroendocrine neoplasm in a patient with primary sclerosing cholangitis: A case report

INTRODUCTION AND IMPORTANCE

Primary hepatic neuroendocrine neoplasms(PHNEN) are among the rarest primitive neuroendocrine neoplasms. Main prognostic factor is histological. We report an unusual case of a PHNEN with 21 years of evolution in the setting of a primary sclerosing cholangitis(PSC).

CASE PRESENTATION

A 40 year old man presented in 2001 with clinical signs of obstructive jaundice. CT-scan and MRI showed a 4 cm large hypervascular proximal hepatic mass evoking hepatocellular carcinoma(HCC) or cholangiocarcinoma. Exploratory laparotomy found an aspect of advanced chronic liver disease of the left lobe. Extemporaneous biopsy of a suspicious nodule showed signs of cholangitis. Left lobectomy was performed and postoperatively the patient received ursodeoxycholic-acid and biliary stenting. After 11 years of follow-up, jaundice reappeared with a stable hepatic lesion.A percutaneous liver biopsy was done. Pathology showed a G1 neuroendocrine tumor. Endoscopy, imagery and Octreoscan were normal, supporting the diagnosis of PHNEN. PSC was diagnosed on tumor-free parenchyma. The patient is on liver transplantation waiting list.

CLINICAL DISCUSSION

PHNENs are exceptional. Pathology findings, endoscopy and imagery are necessary to rule out an extra hepatic NEN with liver metastasis. While G1 NEN are known for their slow evolution, this 21 year latency is extremely rare. The presence of PSC adds to the complexity of our case. Surgical resection is recommended when possible.

CONCLUSION

This case showcases the extreme latency of some PHNEN as well as possible overlap with PSC. Surgery is the most recognized treatment. Liver transplantation seems to be necessary for us, as the rest of the liver shows signs of PSC.

Correlation of four-phase CT findings of rectal neuroendocrine neoplasms with different World Health Organization grades

PURPOSE

To investigate the four-phase computed tomography (CT) features of rectal neuroendocrine neoplasms (R-NENs) as they relate to different World Health Organization pathological grades.

METHODS

A total of 42 patients who underwent pre-operative four-phase CT for evaluation of neoplasms confirmed as different pathological grades of R-NENs by surgery were included. The CT features were retrospectively analyzed by two radiologists in consensus including the tumor location, shape, long diameter, necrosis, boundary, transmural invasion, CT attenuation values of noncontrast and different enhancement phases, intra mesenteric metastasis, lateral lymph node metastasis, and distant metastasis. The differences among R-NENs of different pathological grades were analyzed using T-test, analysis of variance, and non-parametric rank sum test.

RESULTS

Among 42 cases (23 males, 19 females, aged 57 ± 10.48 years) of R-NENs, neuroendocrine tumors G1, G2, and G3 (NET G1, NET G2, NET G3) and neuroendocrine carcinoma (NEC) were 13, 13, 3 and 13 cases, respectively. There were statistically significant differences in tumor long diameter, shape, necrosis, boundary, transmural invasion, CT values in delayed phase, intra mesenteric metastasis, lateral lymph node metastasis, and liver metastasis of different pathological grades (P < 0.001, P = 0.014, P = 0.004, P < 0.001, P < 0.001, P = 0.038, P = 0.006, P = 0.022, and P = 0.020, respectively).

CONCLUSION

Features on four-phase CT can correlate with WHO pathological grades of R-NENs; this may be helpful for preoperative diagnosis and prognosis evaluation.

Diagnostic Management of Gastroenteropancreatic Neuroendocrine Neoplasms: Technique Optimization and Tips and Tricks for Radiologists

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) comprise a heterogeneous group of neoplasms, which derive from cells of the diffuse neuroendocrine system that specializes in producing hormones and neuropeptides and arise in most cases sporadically and, to a lesser extent, in the context of complex genetic syndromes. Furthermore, they are primarily nonfunctioning, while, in the case of insulinomas, gastrinomas, glucagonomas, vipomas, and somatostatinomas, they produce hormones responsible for clinical syndromes. The GEP-NEN tumor grade and cell differentiation may result in different clinical behaviors and prognoses, with grade one (G1) and grade two (G2) neuroendocrine tumors showing a more favorable outcome than grade three (G3) NET and neuroendocrine carcinoma. Two critical issues should be considered in the NEN diagnostic workup: first, the need to identify the presence of the tumor, and, second, to define the primary site and evaluate regional and distant metastases. Indeed, the primary site, stage, grade, and function are prognostic factors that the radiologist should evaluate to guide prognosis and management. The correct diagnostic management of the patient includes a combination of morphological and functional evaluations. Concerning morphological evaluations, according to the consensus guidelines of the European Neuroendocrine Tumor Society (ENETS), computed tomography (CT) with a contrast medium is recommended. Contrast-enhanced magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI), is usually indicated for use to evaluate the liver, pancreas, brain, and bones. Ultrasonography (US) is often helpful in the initial diagnosis of liver metastases, and contrast-enhanced ultrasound (CEUS) can solve problems in characterizing the liver, as this tool can guide the biopsy of liver lesions. In addition, intraoperative ultrasound is an effective tool during surgical procedures. Positron emission tomography (PET-CT) with FDG for nonfunctioning lesions and somatostatin analogs for functional lesions are very useful for identifying and evaluating metabolic receptors. The detection of heterogeneity in somatostatin receptor (SSTR) expression is also crucial for treatment decision making. In this narrative review, we have described the role of morphological and functional imaging tools in the assessment of GEP-NENs according to current major guidelines.

Neuroendocrine neoplasm imaging: protocols by site of origin

With the relatively low incidence of neuroendocrine neoplasms (NEN), most radiologists are not familiar with their optimal imaging techniques. The imaging protocols for NENs should be tailored to the site of origin to accurately define local extension of NEN at time of staging. Patterns of spread and recurrence should be taken into consideration when choosing protocols for detection of recurrence and metastases. This paper will present the recommended CT and MRI imaging protocols for gastro-enteric and pancreatic NENs based on site of origin or predominant pattern of metastatic disease, and explain the rationale for MRI contrast type, contrast timing, as well as specific sequences in MRI. We will also briefly comment on PET/CT and PET/MRI imaging protocols.

Gastric neuroendocrine neoplasms: a primer for radiologists

Gastric neuroendocrine neoplasms are uncommon tumors with variable differentiation and malignant potential. Three main subtypes are recognized: type 1, related to autoimmune atrophic gastritis; type 2, associated with Zollinger-Ellison and MEN1 syndrome; and type 3, sporadic. Although endoscopy alone is often sufficient for diagnosis and management of small, indolent, multifocal type 1 tumors, imaging is essential for evaluation of larger, high-grade, and type 2 and 3 neoplasms. Hypervascular intraluminal gastric masses are typically seen on CT/MRI, with associated perigastric lymphadenopathy and liver metastases in advanced cases. Somatostatin receptor nuclear imaging (such as Ga-68-DOTATATE PET/CT) may also be used for staging and assessing candidacy for peptide receptor radionuclide therapy. Radiotracer uptake is more likely in well-differentiated, lower-grade tumors, and less likely in poorly differentiated tumors, for which F-18-FDG-PET/CT may have additional value. Understanding disease pathophysiology and evolving histologic classifications is particularly useful for radiologists, as these influence tumor behavior, preferred imaging, therapy options, and patient prognosis.

Small bowel neuroendocrine neoplasm: what surgeons want to know

Neuroendocrine neoplasms of the small bowel are a diverse group of tumors with a broad spectrum of imaging findings and clinical implications. Most tumors originate in close proximity to the ileocecal valve and most commonly metastasize to the mesentery and liver. This review will highlight the imaging findings of primary and metastatic small bowel neuroendocrine neoplasm that are most relevant to the surgical team.

Performance of Multidetector Computed Tomography and Negative Versus Positive Enteric Contrast for Evaluation of Gastrointestinal Neuroendocrine Neoplasms

BACKGROUND

Routine computed tomography (CT) scans are thought to have poor performance for detection of gastrointestinal (GI) neuroendocrine neoplasms (NENs), which leads to delayed workup. Detection of even 1 bowel tumor can guide diagnostic workup and management. The purposes of this study were to assess the accuracy of multidetector computed tomography (MDCT) and to compare negative versus positive enteric contrast in detecting at least 1 GI tumor per patient with suspected or confirmed diagnosis of a NEN.

METHODS

This retrospective study included 107 patients with intravenous and oral contrast (65 positive, 40 negative, and 2 no oral contrast) abdominopelvic MDCT. Two abdominal radiologists independently analyzed the CTs for detection and localization of bowel NENs. Surgical pathology was considered the reference standard. Analyses included κ and summary statistics, McNemar test, Pearson χ2 test, and Fisher exact test.

RESULTS

Among the 107 CT scans, there were 30 pathology negative studies and 77 studies with positive pathology for GI NEN. Interreader agreement for CT evaluation was substantial (κ = 0.61). At least 1 GI NEN per patient was detected with 51% to 53% sensitivity, 87% to 93% specificity, 91% to 95% positive predictive value (PPV), 42% negative predictive value, and 63% accuracy for each reader, and 57% accuracy when only the concordant (ie, matching) results of the 2 readers were considered. Computed tomography scans with negative enteric contrast had significantly higher sensitivity for concordant results than CTs with positive enteric contrast (58% vs 30%, P = 0.01). Specificity (100% vs 95%, P = 0.5), PPV (100% vs 93%, P = 0.49), negative predictive value (39% vs 39%, P = 0.99), and accuracy (67% vs 51%, P = 0.10) were not significantly different for negative versus positive enteric contrast for the concordant results. There was no significant difference in GI NEN localization between the readers.

CONCLUSIONS

Routine MDCT with either positive or negative enteric contrast can detect at least 1 GI tumor per patient with more than 90% PPV and more than 50% accuracy in patients suspected of GI NEN. Using negative enteric contrast improves sensitivity for GI NEN versus positive enteric contrast. In addition, there is high accuracy in localizing the bowel tumor with positive or negative enteric contrast, which may guide surgery. Radiologists should have heightened awareness that evaluating such scans closely may lead to detection of primary bowel NENs at a higher rate than previously reported.

Gastric neuroendocrine neoplasms: A review

Gastric neuroendocrine neoplasms (g-NENs) or neuroendocrine tumors are generally slow-growing tumors with increasing incidence. They arise from enterochromaffin like cells and are divided into four types according to clinical characteristic features. Type 1 and 2 are gastrin dependent, whereas type 3 and 4 are sporadic. The reason for hypergastrinemia is atrophic gastritis in type 1, and gastrin releasing tumor (gastrinoma) in type 2 g-NEN. The diagnosis of g-NENs needs histopathological investigation taken by upper gastrointestinal endoscopy. g-NENs are positively stained with chomogranin A and synaptophysin. Grading is made with mitotic index and ki-67 proliferation index on histopathological analysis. It is crucial to discriminate between types of g-NENs, because the management, treatment and prognosis differ significantly between subtypes. Treatment options for g-NENs include endoscopic resection, surgical resection with or without antrectomy, medical treatment with somatostatin analogues, netazepide or chemotherapy regimens. Follow-up without excision is another option in appropriate cases. The prognosis of type 1 and 2 g-NENs are good, whereas the prognosis of type 3 and 4 g-NENs are close to the prognosis of gastric adenocancer.

Immunoglobulin G4-related systemic disease: mesenteric and peritoneal involvement with radiopathological correlation and differential diagnoses

Since its first introduction in 2003 by Kamisawa et al., IgG4-related disease has gained wide interest in the imaging community, and several manuscripts have been published regarding its imaging features. In addition to initial observations in the pancreaticobiliary system, it is now well known that the disease may involve every organ system in the body. There is not much information in the imaging literature about the involvement of mesentery, omentum, and peritoneum in this disease. This article aims to provide more information about the imaging findings of IgG4-related disease regarding these areas by making radiopathological correlations and discussing the possible differential diagnoses.

Duodenal tumors on cross-sectional imaging with emphasis on multidetector computed tomography: a pictorial review

Duodenal tumours are uncommon, but they can cause significant morbidity and mortality. As stomach and colon are a more common site of gastrointestinal malignancies, radiologists sometimes neglect the duodenum. Multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) can accurately locate and characterize mass-forming duodenal lesions, making them invaluable for the differential diagnosis and determining management strategies such as biopsy or surgery. Although conventional endoscopy continues to play an important role in the diagnosis of duodenal tumors, MDCT and MRI are very useful for evaluating the duodenal wall, extraduodenal space, and surrounding viscera, as well as the intraluminal content seen on endoscopy. This pictorial review aims to illustrate the most common benign and malignant mass-forming duodenal lesions and to focus on the imaging features that are most helpful in reaching the correct diagnosis.

Primary renal carcinoid tumors: Three case reports

RATIONALE

Primary renal carcinoid tumors are very rare and only about 100 cases have been reported in the medical literature. There are even fewer articles on the imaging manifestations of primary renal carcinoid tumors.

PATIENT CONCERNS

We present 3 cases of patients with lumbago and hematuria. These were cases of primary renal carcinoid tumors with initial suspicion of suprarenal epithelioma.

DIAGNOSES

Renal lesions were detected on abdomen computed tomography (CT) imaging. The 3 cases presented as solid/cystic solid renal mass with uniform or non-uniform density, calcification in the mass, and enhanced heterogeneity.

INTERVENTIONS

The laparoscopic partial/radical nephrectomy were performed.

OUTCOMES

The postoperative histological diagnosis were primary renal carcinoid tumors. Case 2 been lost to follow-up in 3 patients, and the other 2 patients (Case 1 and 3) are still alive. Case 1 had intrahepatic metastases.

LESSONS

Primary renal carcinoid tumors mostly present as solid mass/cystic solid mass with calcification and delayed enhancement of heterogeneity on CT imaging, but the diagnosis depends on pathological diagnosis. Hence, raising awareness of the CT features of the rare tumor in the kidney may broaden the knowledge base of radiologists.

Imaging neuroendocrine tumors: Characterizing the spectrum of radiographic findings

Neuroendocrine tumors (NET) are a group of neoplasms with neuroendocrine differentiation affecting a wide range of organs. Functional NETs present with symptoms due to the particular hormone produced. Functional NETs are usually small at diagnosis and therefore can be challenging to diagnose. In contrast, non-functioning NETs are generally larger and present with mass effect. Imaging plays an indispensable role in diagnosis, staging and management of patients with NETs. The optimal modality and technique for imaging of NETs depend on the location of primary and metastatic lesions. Regardless of the imaging modality, dynamic contrast-enhanced imaging is essential for evaluation of NETs. In general, CT scan is typically the primary imaging modality for evaluating NETs. MRI is used as a complementary modality, being superior to other modalities to assess liver metastasis. Nuclear medicine imaging is also widely used in NET assessment.

Prediction of the World Health Organization Grade of rectal neuroendocrine tumors based on CT histogram analysis

OBJECTIVES

To investigate the diagnostic value of contrast-enhanced computed tomography (CECT) histogram analysis in predicting the World Health Organization (WHO) grade of rectal neuroendocrine tumors (R-NETs).

MATERIALS AND METHODS

A total of 61 (35 G1, 12 G2, 10 G3, and 4 NECs) patients who underwent preoperative CECT and treated with surgery to be confirmed as R-NETs were included in this study from January 2014 to May 2019. We depicted ROIs and measured the CECT texture parameters (mean, median, 10th, 25th, 75th, 90th percentiles, skewness, kurtosis, and entropy) from arterial phase (AP) and venous phase (VP) images by two radiologists. We calculated intraclass correlation coefficient (ICC) and compared the histogram parameters between low-grade (G1) and higher grade (HG) (G2/G3/NECs) by applying appropriate statistical method. We obtained the optimal parameters to identify G1 from HG using receiver operating characteristic (ROC) curves.

RESULTS

The capability of AP and VP histogram parameters for differentiating G1 from HG was similar in several histogram parameters (mean, median, 10th, 25th, 75th, and 90th percentiles) (all p < 0.001). Skewness, kurtosis, and entropy on AP images showed no significant differences between G1 and HG (p = 0.853, 0.512, 0.557, respectively). Entropy on VP images was significantly different (p = 0.017) between G1 and HG, however, skewness and kurtosis showed no significant differences (p = 0.654, 0.172, respectively). ROC analysis showed a good predictive performance between G1 and HG, and the 75th (AP) generated the highest area under the curve (AUC = 0.871), followed by the 25th (AP), mean (VP), and median (VP) (AUC = 0.864). Combined the size of tumor and the 75th (AP) generated the highest AUC.

CONCLUSIONS

CECT histogram parameters, including arterial and venous phases, can be used as excellent indicators for predicting G1 and HG of rectal neuroendocrine tumors, and the size of the tumor is also an important independent predictor.

Large cell neuroendocrine carcinoma in the unusual location of the descending colon

Neuroendocrine neoplasms are most often found in the small intestine, rectum, appendix, and stomach. The colon, excluding the appendix and the cecum, is a rare location for these neoplasms and often gives rise to highly proliferative, poorly differentiated tumors with aggressive features and dismal prognosis. A 32-year-old male presents with a large cell neuroendocrine carcinoma arising from an unusual location, the descending colon. The patient's clinical and imaging characteristics resembles those seen in the much more common neoplasm, colonic adenocarcinoma. Computed tomography and In-111 octreotide scan are limited in diagnosing large cell neuroendocrine carcinoma. Pathologic correlation of a surgical specimen is required to make the correct diagnosis.

Anatomic and Functional Imaging of Neuroendocrine Tumors

OPINION STATEMENT

Neuroendocrine tumors (NETs) can occur in a wide variety of organs and display a spectrum of pathologic behavior. Accurate and effective imaging is paramount to the diagnosis, staging, therapy, and surveillance of patients with NET. There have been continuous advancements in the imaging of NET which includes anatomic and functional techniques.

Carcinoid Syndrome: A Review

Carcinoid syndrome (CS) is a paraneoplastic syndrome caused by the release of serotonin and other substances from well-differentiated neuroendocrine tumors (NETs). The hallmark symptoms of carcinoid syndrome are flushing and diarrhea; atypical signs and symptoms can include wheezing, abdominal pain, valvular heart disease, telangiectasias, pellagra, and the complications of mesenteric fibrosis, including ureteral obstruction, bowel obstruction, and bowel ischemia. These symptoms are mediated by the release of serotonin (5-HT), histamine, kallikrein, prostaglandins, and tachykinins. The diagnosis of CS requires these symptoms and corresponding elevations in lab tests. Treatment options include surgery and medical management with somatostatin analogs.

Multiple liver metastases originating from synchronous double cancer of neuroendocrine tumor and rectal cancer: a case report

Background

Neuroendocrine tumor (NET) is a relatively rare tumor and can develop in almost any organ, but primary mesenteric NETs are extremely rare. In addition, liver metastases from synchronous double cancer of neuroendocrine tumor graded as G1 and second primary malignancies (SPMs) have never been reported before. We herein report a case of multiple liver metastases from synchronous double cancer of NET (G1) at the ileal mesentery and rectal cancer.

Case presentation

A 66-year-old man was identified as having tumors in the rectum and the ileal mesentery by computed tomography (CT). He underwent laparoscopic low anterior resection for rectal cancer and biopsy of the ileal mesentery lymph node and was diagnosed with rectal cancer as pT3 pN1 cM0 (stage IIIB) and NET (G1) of the ileal mesentery. He received oxaliplatin and capecitabine (XELOX) for 3 months as adjuvant chemotherapy for rectal cancer. The NET (G1) of the ileal mesentery was low grade and had not expanded at follow-up. A CT scan performed 4 years after the surgery indicated multiple liver metastases. All the metastases had the same findings on CT and magnetic resonance imaging (MRI). Thus, the patient underwent the first stage of modified associating liver partition and portal vein ligation for staged hepatectomy (modified ALPPS), comprising partial hepatectomies of segments 3 and 4, ligation of the right branch of portal vein, and hepatic partition on the demarcation line, followed by the second stage of modified ALPPS (right lobectomy). Histopathological findings revealed that the 14 nodules were metastatic liver tumors of rectal cancer and the 2 nodules were liver metastases of the NET (G1).

Conclusions

Our findings suggest that synchronous double cancer of NET and gastrointestinal cancer may be indistinguishable in preoperative images. However, curative resection, precise pathological diagnosis, and adequately adjusted treatment may result in a better prognosis.

Appendicular neoplasms and consequences in patients undergoing surgery for suspected acute appendicitis

INTRODUCTION

In patients treated with an appendectomy for acute appendicitis, the specimen is generally sent for histological evaluation. In an era of increasing non-operative treatment for acute appendicitis, it is important to know the incidence, the diagnostic accuracy, and treatment consequences of appendicular neoplasms that are found in acute appendicitis. We hypothesize that pre- and intra-operative parameters might predict an appendicular neoplasm.

METHODS

Data was used from our previous prospective observational cohort study. All patients undergoing surgery for suspected acute appendicitis were included. The primary outcome was the incidence of appendicular neoplasms in patients operated for acute appendicitis. Secondary outcomes were pre-operative diagnostics and imaging outcomes, intra-operative surgical judgment, and postoperative management and outcome. Possible predictors of an appendicular neoplasm were identified and used in multivariable logistic regression. Patients with an appendicular neoplasm were followed for 3 years after initial appendectomy.

RESULTS

A total of 1975 patients underwent surgery for suspected acute appendicitis and in 98.3% (1941/1975) the appendix was removed. In 1.5% (30/1941) of these patients, an appendicular neoplasm was found. Among the malignant neoplasms, the majority were grade 1 neuroendocrine tumors (NET) in 65% (13/20). On pre-operative imaging, there was no suspicion of malignancy. In three cases, there was an intra-operative suspicion of malignancy. Multivariable analysis showed only age as an independent predictor for appendicular neoplasms. No recurrent or new malignancy was found during follow-up.

DISCUSSION

The incidence of appendicular neoplasm in patients undergoing an acute appendectomy is very low and clinical risk factors could not be identified.

Disorders of neural crest derivates in oncoradiological practice

Hundreds of articles discuss the imaging characteristics and molecular background of prominent gastrointestinal (GI) motility disorders and tumors of the peripheral nervous system, but according to our knowledge an article focusing on the classification and developmental background of these heterogeneous diseases is not to be found. Our aim is to give insight on the common features of several diseases and tumors, starting with their common source of origin, the neural crest (NC). The NC is a transient cell population of the embryo, which differentiates into several organs/structures of our body (sympathetic trunk, adrenal medulla). Although the incidence of the individual tumors of NC cells is not high by themselves, the summation of these incidences may be relevant in the daily routine. In the introduction we mention the most prominent developmental routes and molecular pathways of NC cells, which is crucial to understand the pathogenesis and the wide range of involved cell types from the colon to the adrenal gland. We summarized the most important, useful pathological findings and imaging techniques from the X-ray to the positron emission tomography—computed tomography (CT) in order to help the identification of these diseases. This article may help to better understand NC lineage and its unique, diverse role during ontogeny, which may influence the radiologists to change several convictions, or understand better the background and/or connections of a wide range of tumors and syndromes.

CT detection of primary and metastatic ileal carcinoid tumor: rates of missed findings and associated delay in clinical diagnosis

PURPOSE

To determine the rate of missed CT findings of ileal carcinoid tumor prior to pathologic diagnosis and the resultant diagnostic delay.

METHODS

Initially, 74 patients with abdominal and pelvic CT prior to pathologically-proven diagnosis of ileal carcinoid were identified. Patients were excluded when the original CT study (n = 6) or report (n = 4) was not available, resulting in a final cohort of 64 patients (mean age, 58.3 years; 29 M/35F); 27 (42%) patients had more than one abdominal CT prior to diagnosis. All available CT studies prior to diagnosis were retrospectively reviewed for the presence of the primary ileal tumor and metastatic disease (mesenteric and hepatic).

RESULTS

Primary ileal tumors were prospectively missed on at least one CT scan in 64% (32/50) of patients with retrospectively identifiable disease. CT findings of mesenteric spread were missed at least once in 46% (25/54) of cases where present in retrospect. By the final pre-operative CT, hepatic metastases and bowel wall thickening were present in 55% (35/64) and 52% (33/64) of cases, respectively. In patients with missed ileal and/or mesenteric findings resulting in diagnostic delay, mean delay was 40 months (range 4-98 months).

CONCLUSION

Initial presentation of ileal carcinoid tumor, even with mesenteric involvement, is often missed prospectively at abdominal CT, leading to delay in diagnosis until bowel or mesenteric findings become more obvious, or hepatic metastatic disease manifests. Radiologists should make a concerted effort to evaluate the bowel and mesentery in patients with long-standing vague abdominal symptoms.

Dual-phase computed tomography angiography of intestinal carcinoid tumor as a lead point for cecocolic intussusception in a dog

In an 8-year-old Labrador Retriever with progressive anorexia, constipation, and depression, CT revealed intussusception of the cecum into the ascending colon and a small cecal mass showing strong enhancement on arterial phase. The ileocecocolic junction was surgically resected and histologically diagnosed as cecocolic intussusception with carcinoid tumor. The carcinoid tumor worked as a lead point of intussusception in this case. Dual phasic CT is useful to assess the presence of gastrointestinal tumors as lead points in old dogs with intussusception.

Multimodality Imaging of Ileal Neuroendocrine (Carcinoid) Tumor

OBJECTIVE. The purpose of this article is to provide a multimodality imaging review of ileal carcinoid tumor. CONCLUSION. Ileal carcinoid tumors display a variety of radiologic findings. Delay in diagnosis is common because of initial nonspecific symptoms and subtle imaging findings. Reviewing the multimodality imaging appearance of the primary tumor, metastatic disease, and associated ancillary findings can help improve patient care.

Usefulness of Capsule Endoscopy and Double-balloon Enteroscopy for the Diagnosis of Multiple Carcinoid Tumors in the Small Intestine: Case Reports and a Literature Review

The incidence of carcinoid tumor in the small intestine is increasing; however, its preoperative diagnosis is difficult. We recently experienced three cases of multiple carcinoid tumors in the small intestine successfully detected using capsule endoscopy (CE), followed by a pathological diagnosis using double-balloon enteroscopy (DBE). To diagnose multiple carcinoid in the small intestine appropriately, we reviewed the information of five cases reported to date along with our three recent cases. The literature review demonstrated that CE and DBE are useful for detecting and diagnosing small intestinal carcinoids and tumor multiplicity, which aids in determining the appropriate resection range.

Diagnostic imaging of gastrointestinal neuroendocrine tumours (GI-NETs): relationship between MDCT features and 2010 WHO classification

AIMS

We aimed to present our series of gastrointestinal neuroendocrine tumours (GI-NETs) in order to illustrate and highlight the associated contrast-enhanced multi-detector computed tomography (MDCT) features. We also attempted to identify a relationship between MDCT imaging and the 2010 World Health Organization (WHO) classification system.

MATERIALS AND METHODS

We selected all patients with pathologically proven GI-NETs diagnosed between January 2010 and August 2017. Only patients undergone contrast-enhanced MDCT imaging in the immediate preoperative period were included in our study. Later, two expert radiologists retrospectively assessed MDCT intestinal and extra-intestinal signs. We also analysed the relationship between MDCT imaging and the 2010 WHO classification.

RESULTS

A total of 20 patients (13 males, 7 females, age range 37-89 years, mean age 69.9 years) were included in our study. The majority of GI-NETs (85%) occurred in the small bowel and mainly in the terminal ileum. Forty-five percentage of our GI-NETs were diagnosed after an access to emergency medical service for obstruction symptoms or gastrointestinal bleeding. Regarding intestinal signs, 15/20 patients showed an intraluminal nodular mass and 5/20 a wall thickening. Extra-intestinal signs were present in 75% of cases. Desmoplastic reaction and lymph nodes metastases were significantly correlated with higher grade of GI-NETs.

CONCLUSIONS

The majority of GI-NETs appears as intraluminal mass often associated with extra-intestinal signs. We found a significantly correlation between higher grade of GI-NETs and extra-intestinal signs. MDCT imaging may be useful in predicting the pathological classification of GI-NETs.

Dual Energy Computed Tomography Scans of the Bowel: Benefits, Pitfalls, and Future Directions

Current computed tomography bowel imaging is challenging given the variable distension, content, and location of the bowel, the different appearance of tumors within and adjacent to bowel, and peristaltic artifacts. Published data remain sparse. Derangements in enhancement may be highlighted, image artifacts reduced, and radiation dose from multiphase scans minimized. This modality is suited for imaging bowel tumor detection and characterization, gastrointestinal bleeding, and bowel inflammation, and ischemia. Experimental results on computed tomography colonography and novel bowel contrast material offer hope for major improvements in bowel interrogation. It is likely to become increasingly valuable for bowel-related disease diagnosis and monitoring.

Magnetic Resonance Enterography for Inflammatory and Noninflammatory Conditions of the Small Bowel

Magnetic resonance enterography (MRE) is an effective noninvasive tool for evaluation of inflammatory and noninflammatory conditions of the small bowel. MRE allows for repeated evaluation of patients with Crohn disease without exposure to ionizing radiation, and can be used to assess disease status and direct management. MRE also allows evaluation of neoplastic and other nonneoplastic conditions of the small bowel. Adequate patient preparation and acquisition techniques are required for optimal image quality.

Midgut neuroendocrine tumor presenting with acute intestinal ischemia

Neuroendocrine tumors represent a heterogeneous group of neoplasms that arise from neuroendocrine cells and secrete various peptides and bioamines. While gastrointestinal neuroendocrine tumors, commonly called carcinoids, account for about 2/3 of all neuroendocrine tumors, they are relatively rare. Small intestine neuroendocrine tumors originate from intestinal enterochromaffin cells and represent about 1/4 of small intestine neoplasms. They can be asymptomatic or cause nonspecific symptoms, which usually leads to a delayed diagnosis. Imaging modalities can aid diagnosis and surgery remains the mainstay of treatment. We present a case of a jejunal neuroendocrine tumor that caused nonspecific symptoms for about 1 year before manifesting with acute mesenteric ischemia. Abdominal X-rays revealed pneumatosis intestinalis and an abdominal ultrasound and computed tomography confirmed the diagnosis. The patient was submitted to segmental enterectomy. Histopathological study demonstrated a neuroendocrine tumor with perineural and arterial infiltration and lymph node metastasis. The postoperative course was uneventful and the patient denied any adjuvant treatment.

Management of neuroendocrine tumors of unknown primary

Neuroendocrine neoplams (NENs) are mostly relatively indolent malignancies but a significant number have metastatic disease at diagnosis mainly to the liver. Although in the majority of such cases the primary origin of the tumor can be identified, in approximately 11-22% no primary tumor is found and such cases are designated as NENs of unknown primary origin (UPO). This has significant therapeutic implications with respect to potentially resectable hepatic disease and/or application of appropriate medical therapy, either chemotherapeutic agents or targeted treatment, as the response to various treatments varies according to the origin of the primary tumor. This lack of tumor specific orientated treatment may also account for the relatively poorer prognosis of NENs of UPO compared to metastatic NENs with a known primary site. In the majority of cases the primary tumors are located in the small bowel and the lung, but a number may still elude detection. Occasionally the presence of a functional syndrome may direct to the specific tissue of origin but in the majority of cases a number of biochemical, imaging, histopathological and molecular modalities are utilized to help identify the primary origin of the tumor and direct treatment accordingly. Several diagnostic algorithms have recently been developed to help localize an occult primary tumor; however, in a number of cases no lesion is identified even after prolonged follow-up. It is expected that the delineation of the molecular signature of the different NENs may help identify such cases and provide appropriate treatment.

UNBS5162 inhibits the proliferation of esophageal cancer squamous cells via the PI3K/AKT signaling pathway

C‑X‑C motif chemokine ligand (CXCL) signaling has been demonstrated to be involved in cancer invasion and migration; therefore, CXCL antagonists may serve as anticancer drugs by preventing tumor proliferation. The present study aimed to investigate whether a pan antagonist of CXCLs, UNBS5162, may inhibit esophageal cancer proliferation and to identify the underlying mechanisms. Cell proliferation and cell colony formation results, which were determined by a Cell Counting Kit‑8 assay and crystal violet staining, respectively, demonstrated that UNBS5162 inhibited esophageal cancer cell proliferation. Following treatment with UNBS5162, Transwell migration and Matrigel invasion assays, and flow cytometry with Annexin V‑fluorescein isothiocyanate and propidium iodide staining, were performed to investigate cell migration, invasion and apoptosis in human esophageal cancer cells. The results indicated that invasion and migration was reduced in UNBS5162‑treated cells, while apoptosis was increased. Western blotting experiments confirmed that UNBS5162 downregulated the protein expression of proteins associated with the phosphatidylinositol 3‑kinase (PI3K)/AKT signaling pathway, including the levels of phosphorylated (p)‑AKT, p‑mechanistic target of rapamycin kinase, ribosomal protein S6 kinase β1 and cyclin D1. In addition, upregulated expression of programed cell death 4 was observed following UNBS5162 treatment. The present study demonstrated that UNBS5162 is a novel naphthalimide that may have potential therapeutic use for the prevention of esophageal cancer proliferation and metastasis via the PI3K/AKT signaling pathway.

Multimodality Imaging Findings in Carcinoid Tumors: A Head-to-Toe Spectrum

Carcinoid tumors are a rare biologically heterogeneous group of neuroendocrine tumors with a spectrum ranging from benign indolent to aggressive metastatic tumors. They belong to the category of amine precursor uptake and decarboxylase tumors, or apudomas. The most common sites for primary locations are the gastrointestinal and respiratory tracts; however, any organ can be involved. The clinical presentation depends on location, aggressiveness, production of biologically active amines and peptides, paraneoplastic syndromes, and tendency for metastasis. Their reported age-adjusted incidence has increased in recent years, partly due to improved detection at radiologic imaging and endoscopy. Not a ll neuroendocrine cell tumors are carcinoids. Numerous systems have been proposed regarding their nomenclature and classification. Cross-sectional and functional imaging plays an important role in diagnosis, lesion characterization, and staging. Awareness of nomenclature, classification, common sites of involvement, and imaging presentation are pivotal for making the diagnosis. Knowledge of the diverse clinical, pathologic, and radiologic spectrum of carcinoid tumors involving various organs of the body is important for diagnosis and patient management. ^©RSNA, 2017.

Magnetic Resonance Imaging of Neuroendocrine Tumor Hepatic Metastases: Does Hepatobiliary Phase Imaging Improve Lesion Conspicuity and Interobserver Agreement of Lesion Measurements?

OBJECTIVE

The aim of this study was to determine if magnetic resonance imaging (MRI) performed with hepatobiliary phase imaging results in higher lesion conspicuity and produces lesion measurements with higher interobserver agreement than other MRI sequences when imaging neuroendocrine hepatic metastases.

METHODS

Patients who had MRIs with both gadoxetate disodium and gadopentetate dimeglumine contrast within a 6-month span were identified, and 23 hepatic lesions were selected. Three radiologists and 1 oncologist measured the greatest diameter of each lesion on the following sequences: T2 weighted, T1 weighted, postcontrast (dynamic, delayed, and hepatobiliary phase), and diffusion weighted. Signal intensity ratio (SIlesion/SIliver) and contrast-to-noise ratio ([SIlesion - SIliver]/noise) were calculated for all lesions on each sequence. The interobserver agreement of measurements on each sequence was calculated using concordance correlation coefficient.

RESULTS

Diffusion-weighted sequences had the highest signal intensity ratio ranging from 147% to 187% (vs other sequences range of 19.6%-130%). One hepatobiliary sequence had the highest contrast-to-noise ratio with a value of 41 (vs other sequences range of 3.2-28.1). Lesion measurements on all sequences showed high-interobserver agreement, with hepatobiliary sequences showing some of the highest levels of agreement.

CONCLUSIONS

Our results support the use of contrast agents with hepatobiliary excretion when imaging neuroendocrine tumors metastatic to liver.

Imaging of Neuroendocrine Tumors: Indications, Interpretations, Limits, and Pitfalls

Imaging is critical in the diagnosis, prognosis, and management of neuroendocrine tumors (NETs). NETs share common imaging features, but each type exhibits unique features. Computed tomography scans or MRI of the abdomen is used to assess tumor burden routinely. Functional imaging with octreotide scan or gallium-68 somatostatin analog PET is used selectively to confirm diagnosis and guide therapy. Clinicians and radiologists should be familiar with the indications and interpretations of imaging modalities. Novel functional imaging modalities likely will be developed to detect small NETs, predict prognosis, guide therapeutic choices, and design novel therapies.

Predicting appendiceal tumors among patients with appendicitis

BACKGROUND

As nonoperative management of appendicitis gains popularity, vigilance for appendiceal tumors becomes increasingly important. We hypothesized that, among patients presenting with acute appendicitis, those with advanced age, multiple comorbidities, atypical presentation, and complicated appendicitis would be more likely to have underlying appendiceal tumors.

METHODS

We performed a 4-year retrospective cohort analysis of 677 consecutive adult patients who underwent appendectomy for appendicitis at our tertiary care center. Patients with an appendiceal tumor on their final pathology report were compared to patients with no tumor. Conditions present on admission were used to create a multivariate logistic regression model to predict appendiceal tumor. Risk factors were reported as odds ratio (OR) [95% CI]. Model strength was assessed by area under the receiver operating characteristic curve.

RESULTS

Seventeen patients (2.5%) had an appendiceal tumor. Within this group. 14 underwent immediate appendectomy, two initially had nonoperative management but failed to improve on antibiotics and underwent appendectomy during the initial admission, and one had successful nonoperative management and elective appendectomy 19 days after discharge. Four variables contributed to the multivariate model to predict the presence appendiceal tumor: age ≥ 50 (OR 3.6 [1.1-11.4]), outpatient steroid/immunosuppressant use (OR 12.1 [2.0-72.5]), the absence of migratory right lower quadrant pain (OR 4.7 [1.2-18.1]), and the appearance of a phlegmon on CT scan (OR 7.0 [1.6-30.2]); model area under the receiver operating characteristic curve: 0.860 [0.705-0.969].

CONCLUSION

For patients presenting with acute appendicitis, conditions present on admission may predict underlying appendiceal tumor. Patients with advanced age, multiple comorbidities, atypical presentation, and complicated appendicitis should be considered for appendectomy during the index admission or at earliest convenience if nonoperative management is necessary.

LEVEL OF EVIDENCE

Prognostic study, level III.

Diagnosis and management of gastrointestinal neuroendocrine tumors: An evidence-based Canadian consensus

The majority of neuroendocrine tumors originate in the digestive system and incidence is increasing within Canada and globally. Due to rapidly evolving evidence related to diagnosis and clinical management, updated guidance on the diagnosis and treatment of gastrointestinal neuroendocrine tumors (GI-NETs) are of clinical importance. Well-differentiated GI-NETs may exhibit indolent clinical behavior and are often metastatic at diagnosis. Some NET patients will develop secretory disease requiring symptom control to optimize quality of life and clinical outcomes. Optimal management of GI-NETs is in a multidisciplinary environment and is multimodal, requiring collaboration between medical, surgical, imaging and pathology specialties. Clinical application of advances in pathological classification and diagnostic technologies, along with evolving surgical, radiotherapeutic and medical therapies are critical to the advancement of patient care. We performed a systematic literature search to update our last set of published guidelines (2010) and identified new level 1 evidence for novel therapies, including telotristat etiprate (TELESTAR), lanreotide (CLARINET), everolimus (RADIANT-2; RADIANT-4) and peptide receptor radionuclide therapy (PRRT; NETTER-1). Integrating these data with the clinical knowledge of 16 multi-disciplinary experts, we devised consensus recommendations to guide state of the art clinical management of GI-NETs.

De-misty-fying the mesentery: an algorithmic approach to neoplastic and non-neoplastic mesenteric abnormalities

Mesenteric abnormalities are often incidentally discovered on cross-sectional imaging performed during daily clinical practice. Findings can range from the vague "misty mesentery" to solid masses, and the possible etiologic causes encompass a wide spectrum of underlying pathologies including infectious, inflammatory, and neoplastic processes. Unfortunately, the clinical and imaging findings are often non-specific and may overlap. This article discusses the various diseases that result in mesenteric abnormalities. It provides a framework to non-invasively differentiate these entities, when possible.

Incidental Detection of Neuroendocrine Carcinoma of Rectum During Staging Workup of Renal Cell Carcinoma

Malignancies of rectum and kidneys are common pathologies in clinical practice; however, the incidence of these malignancies coexisting together is unclear. The main purpose of this article was to show the usefulness of computed tomography (CT) in diagnosing these rare synchronous tumors. We report a case of neuroendocrine carcinoma of the rectum in a 57-year-old male patient who came for staging workup of renal cell carcinoma (RCC) of the left kidney. To our knowledge, this is the first case of synchronous RCC and rectal neuroendocrine carcinoma coexisting in the same patient.

Mesenteric changes in an ultrasound examination can facilitate the diagnosis of neuroendocrine tumors of the small intestine

Neuroendocrine tumors make up an interesting pathology of a variable clinical picture, prognosis, localization, endocrine activity and degree of malignancy.

The Role of Plasma Chromogranin A as Assessment of Treatment Response in Non-functioning Gastroenteropancreatic Neuroendocrine Tumors

PURPOSE

Chromogranin A (CgA) has been considered to be valuable not only in the diagnosis but also in monitoring the disease response to treatment. However, only a few studies have been published on this issue. We purposed to evaluate whether biochemical response using plasma CgA level is reliable in concordance with the clinical response of grade 1-3 nonfunctiong gastroenteropancreatic neuroendocrine tumors (GEP-NETs).

MATERIALS AND METHODS

Between March 2011 and September 2013, a total of 27 cases in 18 patients were analysed, clinically and radiologically while serial CgA tests were also conducted during treatment. Tumor responses were defined by both Response Evaluation Criteria in Solid Tumors (RECIST) criteria ver. 1.1 and biochemical criteria based on the CgA level.

RESULTS

Among the 27 cases analysed, no difference in the basal CgA level was observed with regard to gender, primary tumor site, tumor grade (World Health Organization classification), liver metastasis, number of metastatic site, and line of chemotherapy. The overall response rate (RR) by RECIST criteria ver. 1.1 was six out of the 27 cases (22.2%) and eight out of the 27 cases (29.6%) for biochemical RR. The overall concordance rates of the response based on RECIST and biochemical criteria were 74%. In grades 1 and 2 GEP-NETs (n=17), the concordance rate of the disease control was 94.1%. There was a significant difference for progression-free survival (PFS) between responders and non-responder in accordance to biochemical criteria (35.73 months vs. 5.93 months, p=0.05).

CONCLUSION

This study revealed that changes of the plasma CgA levels were associated with tumour response. Additionally, biochemical response based on serial CgA may be a predictive marker for PFS in GEP-NETs.