Neuroendocrine tumors of the pancreas: endoscopic diagnosis

Diagnostic Modalities, Management Considerations, and Outcomes of Insulinoma: A Case Series from a Tertiary Care Centre

Introduction

Insulinomas are rare, usually sporadic, and typically benign pancreatic neuroendocrine tumours. Pre-operative localization is challenging and evidence on comparative analysis of anatomic and scintigraphic modalities for pre-operative tumour localization is limited, even in contemporary series.

Methods

The current study was designed to study the clinical features and management challenges of insulinomas managed at a tertiary care centre. Clinical features, diagnosis, imaging techniques, surgical procedures, and outcomes details were collated. Pre-operative imaging techniques (CT/MRI, nuclear scintigraphy) were compared with intraoperative and histopathological findings to assess their accuracy of localization.

Results

Thirty-seven patients (15 females [42%]; median age 36 years [IQR 28-49]) were included in the study. In four patients (10.8%), the tumour occurred in the setting of multiple endocrine neoplasia type 1 (MEN 1) while the remaining were sporadic. The sensitivity of pre-operative localization was 61.5% (multiphasic CT), 66.6% (multiphasic MRI), 100% (68Ga Exendin-4 PET-CT), and 91.6% (EUS). Three patients with normal multiphasic CT had localization on 68Ga Exendin-4 PET-CT. The positive predictive value (PPV) of both Exendin-PET-CT and EUS was similar at 91.6% and 91.6%, respectively. All patients (except one with nesidioblastosis), who underwent enucleation or partial pancreatic resection, were cured.

Conclusion

68Ga Exendin-4 PET-CT based is a non-invasive imaging modality that has high sensitivity and PPV and can be used as a first-line imaging modality. The overall prognosis of these tumours is good with high cure rates attained following surgical resection.

Radiofrequency Ablation of Pancreatic Solid Tumors

Today, endoscopic ultrasound-guided radiofrequency ablation has become increasingly accepted for the treatment of different precancerous and neoplastic lesions of the pancreas, particularly in patients who are unfit for surgery. However, thermal ablation has long been suspected to induce pancreatitis or to injure adjacent structures. Published case reports and case series on this topic are of limited size and are often based on a heterogeneous study population, reporting on functional and nonfunctional pancreatic neuroendocrine tumors. Nevertheless, the overall results are promising, with high technical success and relatively low complication rates.

EUS-guided radiofrequency ablation for pancreatic insulinoma: experience in 2 tertiary centers

BACKGROUND AND AIMS

Insulinoma is the most frequent functional neuroendocrine tumor of the pancreas, and preserving surgery is the treatment of choice. EUS-guided radiofrequency ablation (EUS-RFA) is a novel and promising technique that induces tissue necrosis of localized lesions. This article presents a preliminary clinical experience in treating pancreatic insulinomas <2 cm by EUS-RFA, focusing on safety and efficacy.

METHODS

The clinical course of patients with pancreatic insulinoma treated by EUS-RFA at 2 tertiary referral centers was analyzed.

RESULTS

Between November 2017 and December 2020, 7 patients were included (6 women; mean age, 66 years). EUS-RFA was feasible in all patients with immediate hypoglycemia relief after only 1 single treatment session; 6 of 7 achieved complete response by cross-sectional imaging and remained asymptomatic (median follow-up, 21 months; range, 3-38). Three patients had minor adverse events. One elderly patient developed a large retrogastric collection 15 days after treatment and died 1 month after EUS-RFA.

CONCLUSIONS

Management of pancreatic neuroendocrine tumors <2 cm by EUS-RFA seems to be effective with an acceptable safety profile. However, further evidence focusing on long-term survival and recurrence is needed.

Detection rate of endoscopic ultrasound and computed tomography in diagnosing pancreatic neuroendocrine neoplasms including small lesions: a multicenter study

BACKGROUND/PURPOSE

The detection ability and role of different imaging modalities to detect pancreatic neuroendocrine neoplasms (PNENs) including small lesions is unclear. This study aimed to compare the ability of endoscopic ultrasound (EUS) and computed tomography (CT) to detect PNENs.

METHODS

Data of patients who underwent EUS and contrast-enhanced CT and were diagnosed with PNENs were analyzed. The detection rates of pancreatic lesions with EUS and CT based on tumor size and influencing factors were investigated.

RESULTS

For 256 PNEN lesions, the detection rate of EUS was better than that of CT (94.5% vs. 86.3%; p < 0.001). EUS was significantly superior to CT for PNENs ≤ 5 mm (58.3% vs 16.7%; p = 0.006) and 5-10 mm (97.7% vs 79.5%; p = 0.008). There was no significant difference in the detection rate between EUS and CT for PNENs > 10 mm (98.4% vs 96.4%; p = 0.375). Size (≤ 5 mm) and insulinoma were independent factors associated with poor EUS and CT detection rates.

CONCLUSIONS

EUS exhibited better detection ability than CT, with an excellent detection rate for PNENs > 5 mm, except for insulinomas. CT could detect PNENs > 10 mm, which are amenable to treatment.

What is the appropriate management of nonfunctioning pancreatic neuroendocrine tumours disclosed on screening in adult patients with multiple endocrine neoplasia type 1?

Multiple endocrine neoplasia type 1 (MEN1) is an inherited tumour syndrome characterised by a predisposition to the development of endocrine tumours of the parathyroid glands, pituitary and pancreas: 30%-80% of patients with MEN1 develop pancreatic neuroendocrine tumours (pNETs), with metastatic tumours and/or their sequelae contributing to increased morbidity and early mortality. The optimal management of nonfunctioning (NF) pNETs in MEN1 remains controversial. Whilst pancreatic resection is widely recommended for tumours >2 cm, for smaller tumours (≤2 cm) a well-established consensus guiding the indications for surgical intervention does not exist. Although total pancreatectomy may be curative for some patients, both short- and long-term complications make this an unsatisfactory option for many patients. For small (<2 cm) MEN1 NF-pNETs, some clinicians advocate surveillance based largely on retrospective data that suggest 50%-80% of these lesions are stable over time and infrequently exhibit accelerated growth rates. It is increasingly recognised, however, that NF-pNETs exhibit unpredictable malignant behaviour that is not determined by tumour size alone, thereby prompting other clinicians to advocate surgery for all MEN1 NF-pNETs, irrespective of size. Such uncertainty poses clinical management challenges with regards to the timing and extent of surgery, which is further hindered by the inability to stratify patients based on predicted tumour behaviour. It is therefore critical that future MEN1 research initiatives include: (a) the discovery of biomarkers that better predict tumour behaviour; (b) the evaluation of medical therapies that may delay, or even prevent, the need for pancreatic surgery; and, ultimately, (c) improvement in the quality of life for individuals with MEN1. Here, based on the published literature, we address the Clinical Question, 'What is the management of NF-pNETs disclosed on screening in adult patients with MEN1?'.

Diagnostic performance of endoscopic ultrasound-guided fine-needle aspiration for cystic and non-cystic pancreatic neuroendocrine tumors

Background and study aims  Pancreatic neuroendocrine tumors (P-NENs) are rare tumors with malignant potential. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has been shown to be superior to other imaging methods in preoperative localization and diagnosis of P-NENs. The objective of this study was to describe the EUS features of non-metastatic cystic and non-cystic P-NENs seen at a referral center and to evaluate the performance of EUS-FNA in diagnosis of P-NENs. Patients and methods  All patients with histologically confirmed, non-metastatic P-NENs, which underwent EUS-FNA prior to surgical resection at the Moffitt Cancer Center between Jan 2005 and Dec 2012 were included. Clinical, endoscopic and pathologic information was abstracted from electronic medical records. Results  Thirty-nine patients, all with non-functional P-NENs, were included in this study. Thirteen tumors were cystic and 26 were solid. Among the cystic tumors, 50 % were partly cystic and partly solid, and 50 % were fully cystic. The cystic tumors were more commonly seen at the body/tail, and the solid tumors were more uniformly distributed. Fluid could be aspirated from 50 % of the cystic tumors, all with a carcinoembryonic antigen level < 192 ng/mL. With surgical pathology as the gold standard, overall sensitivity of EUS-FNA in diagnosing cystic tumors was 62.5 %, and for solid tumors, 95 % ( P  < 0.03). Conclusions  EUS-FNA is much more sensitive in diagnosing solid P-NENs than cystic PNETs. Our results indicate that EUS-FNA may have higher sensitivity for diagnosis of cystic P-NENs than the reported sensitivity of EUS-FNA for all pancreatic cystic tumors.

Pancreatic neuroendocrine tumor: review of heterogeneous spectrum of CT appearance

OBJECTIVE

Pancreatic neuroendocrine tumors (PanNETs) are uncommon pancreatic neoplasms and can be a diagnostic challenge with heterogeneous spectrum of CT appearance. We review CT findings of PanNETs and other mimics.

CONCLUSION

PanNETs are typically hypervascular and have avid enhancement on arterial and venous phase images. However, dedicated pancreas protocol may be needed due to their sometimes atypical appearance including transient enhancement. Careful evaluation of CT findings will help differentiate PanNETs from their mimics, and can be used to establish the diagnosis of a PanNETs. Although an accurate diagnosis can be based on serological, urine, and CT scan findings, confirmation is made via pathological examination.

Insulinoma and Chronic Kidney Disease: An Uncommon Conundrum Not to Be Overlooked

A hypertensive man with chronic kidney disease (CKD) secondary to polycystic disease was hospitalized for symptoms related to hypoglycemia. Fasting test elicited symptomatic hypoglycemia after 12 hours, which was associated with inappropriately unsuppressed normal insulin and C-peptide levels. Neither ultrasonography (US) nor magnetic resonance imaging detected any pancreatic tumor. Endoscopic ultrasonography (EUS) showed a small isoechogenic nodule suspect for neuroendocrine tumor in the pancreatic head. ⁶⁸Gallium-DOTA-Tyr³-octreotide positron emission tomography/computed tomography revealed intense uptake by a small region in the pancreatic head. Surgical exploration together with intraoperative US confirmed the nodule in the pancreatic head and evidenced another hypoechogenic one in the uncinate process. Both nodules were enucleated, but only the latter, which had not been previously detected by EUS, proved compatible with insulinoma on combined histology and immunohistochemistry. After nodule enucleation, hypoglycemia resolved and did not relapse. Insulinoma, as a major cause of unexplained hypoglycemia, requires careful hormonal and instrumental workup. In patients with CKD, the interpretation of biochemical criteria for the diagnosis of insulinoma can be challenging. Localization techniques may display pitfalls. Surgery is curative in most patients but long-term follow-up is required.

Rupture of small cystic pancreatic neuroendocrine tumor with many microtumors

Pancreatic neuroendocrine tumors (pNETs) are particularly rare. The various forms of PNETs, such as cystic degeneration, make differentiation from other similar pancreatic lesions difficult. We can detect small lesions by endoscopic ultrasound (EUS) and obtain preoperative pathological diagnosis by EUS-guided fine needle aspiration (FNA). We describe, here, an interesting case of pNET in a 42-year-old woman with no family history. Computed tomography and magnetic resonance imaging revealed an 18 mm × 17 mm cystic lesion with a nodule in the pancreatic tail. Two microtumors about 7 mm in diameter in the pancreatic body detected only by EUS, cystic rim and nodules all showed similar enhancement on contrast-harmonic EUS. Preoperative EUS-FNA of the microtumor was performed, diagnosing multiple pNETs. Macroscopic examination of the resected pancreatic body and tail showed that the cystic lesion had morphologically changed to a 13-mm main nodule, and 11 new microtumors (diameter 1-3 mm). Microscopically, all microtumors represented pNETs. From the findings of a broken peripheral rim on the main lesion with fibrosis, rupture of the cystic pNET was suspected. Postoperatively, pituitary adenoma and parathyroid adenoma were detected. The final diagnosis was multiple grade 1 pNETs with multiple endocrine neoplasia type 1. To the best of our knowledge, no case of spontaneous rupture of a cystic pNET has previously been reported in the English literature. Therefore, this case of very rare pNET with various morphological changes is reported.

Evolving management of insulinoma: Experience at a tertiary care centre

BACKGROUND & OBJECTIVES

Since our previous study in 2006, several new modalities for localization of cause of endogenous hyperinsulinemic hypoglycaemia such as multiphasic computed tomography (CT), multiphasic magnetic resonance imaging (MRI), endoscopic ultrasound (EUS), intraoperative ultrasound, and intra-arterial calcium infusion with arterial stimulation venous sampling (ASVS) have become available. Therefore, to evaluate the relative usefulness of various imaging modalities to guide future management in terms of diagnosis and patient care, we analyzed presentation and management of patients of endogenous hyperinsulinemic hypoglycaemia.

METHODS

In this retrospective study, medical records of patients admitted with endogenous hyperinsulinemic hypoglycaemia were retrieved. Data pertaining to clinical features, diagnosis, imaging, surgery and patient outcome were extracted. The localization of insulinoma by preoperative imaging techniques was compared with the findings at surgery to assess the accuracy of localization.

RESULTS

Fasting hypoglycaemia was present in all, and post-prandial hypoglycaemia (plasma glucose ≤50 mg/dl within four hours of meal) in 25.8 per cent. Mean duration of symptoms before reaching a diagnosis of hyperinsulinemic hypoglycaemia was 3.9 years. Mean duration of provocative fast was 21.8 h (range 6-48 h). Among the currently used imaging modalities, the sensitivity of localizing tumour was 79.3 per cent for multiphasic CT, 85 per cent for multiphasic MRI and 95 per cent for EUS. EUS detected tumour missed by both CT and MRI. All, except one of the operated patients, were cured by surgery.

INTERPRETATION & CONCLUSIONS

Our results suggest that patients with insulinoma have a varied presentation. Multiphasic contrast-enhanced MRI/CT scan, EUS and ASVS may be complimentary in pre-operative localization.

Clinicopathological features and prognosis of gastroenteropancreatic neuroendocrine tumors: analysis from a single-institution

BACKGROUND

The gastroenteropancreatic neuroendocrine neoplasm (GEP-NEN) is the most common type of neuroendocrine neoplasm. We summarized data in our centre to investigate the clinicopathological features, diagnostic methods, therapeutic approaches and prognosis for this neoplasm to increase knowledge of this disease in Asian populations.

METHOD

A total of 122 patients treated at Sun Yet-san Memorial Hospital of Sun Yat-sen University between January 2000 and December 2011 were analyzed retrospectively.

RESULTS

Pancreas was the most common site of involvement (65/122, 53.3%); this disease has no special symptoms; positive rates of chromogranin A (CgA) and synaptophysin (Syn) were 81.1% and 87.7%, respectively. The positive rate of Syn had statistical difference among the three grades, but not CgA. Some 68 patients had G1 tumors, 32 G2 tumors and 22 G3 tumors, and Chi-square test showed that higher grading was correlated with worse prognosis (χ2=32.825, P=0.0001). A total of 32 patients presented with distant metastasis, and 8 cases emerged during following up. Cox proportional hazards regression modeling showed that the tumor grade (P=0.01), lymphatic metastasis (P=0.025) and distant metastasis (P=0.031) were predictors of unfavorable prognosis. The overall 5-year survival rate was 39.6%, the 5-year survival rate of G1 was 55.7%, and the G2 and G3 were 34.2% and 0%, respectively.

CONCLUSIONS

The incidence of gastroenteropancreatic neuroendocrine tumors has risen over the last 12 years. All grades of these diseases metastasize readily, and further research regarding the treatment of patients after radical surgery is needed to prolong disease-free survival.

Nonfunctional Pancreatic Neuroendocrine Tumors: Advances in Diagnosis, Management, and Controversies

In this article, we aimed to review the literature on the clinics and management of nonfunctional pancreatic neuroendocrine tumors (NPNET). Pancreatic neuroendocrine tumors (PNET) are rare tumors with a <1/100,000 incidence and constitute approximately 2 to 10% of all pancreatic tumors. Nonfunctional PNETs are difficult to detect at early stages since they have no symptoms. Except those detected accidentally during different diagnoses, the majority of PNETs are detected in the advanced stages, with symptoms related to tumor size or liver metastasis. We reviewed the studies published in the English medical literature through PubMed and summarized the clinical features and current approaches to the treatment and follow-up of the NPNET. The common imaging techniques used for the detection of tumor localization, size, locoregional, and metastatic involvement are contrasted computed tomography, magnetic resonance imaging, endoscopic ultrasonography, and somatostatin receptor scintigraphy. Surgical resection is the only curative treatment. However, in advanced locoregional disease and liver metastasis, interventive ablative therapies such as palliative reductive surgery, selective hepatic arterial embolization, radiofrequency ablation; and systemic therapies, such as peptide receptor radionuclide therapy, chemotherapy, somatostatin analogous therapy, interferon, VEGF inhibitor, and mTOR inhibitor may be used as symptom relieving or may improve progression-free survival and total survival. Current knowledge on NPNET shows that the treatment should be personalized considering the prognostic features and life expectancy of the patient.

[Endoscopic ultrasound-guided ethanol ablation: an alternative option for the treatment of pancreatic insulinoma]

Endoscopic ultrasound is the most accurate imaging modality for the diagnosis of pancreatic cancer, and endoscopic ultrasound-guided fine needle injection has already been used for palliative interventions. Surgical resection is currently the standard treatment for pancreatic insulinoma. Medical treatment may be necessary for symptomatic patients with unresectable disease. Case reports have been published about the success of endoscopic ultrasound-guided alcoholic ablation, but it has not been reported previously in Hungarian literature. The authors present the history of an 83-year-old woman who was evaluated because of repeated hypoglycemic coma occurring during the night. Endosonographic image and laboratory findings (elevated serum insulin and chromogranin A) revealed pancreatic insulinoma. Because of severe comorbidities and high risk of surgical resection, the decision was made to ablate the insulinoma by endoscopic ultrasound-guided alcohol injection. A total of 3 mL 95% ethanol was injected into the tumor. Despite the discontinuation of the diazoxide therapy the hypoglycemic episodes disappeared. This case history confirms that endoscopic ultrasound-guided alcoholic ablation is a novel, minimal invasive alternative treatment for patients with pancreatic neuroendocrine tumors in whom surgery is not feasible.

Endoscopic diagnosis and treatment of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PNETs) are rare pancreatic neoplasms comprising only 1% to 2% of all pancreatic tumors. In recent years, the number of incidentally discovered PNETs has greatly increased given the widespread use of axial imaging. However, a significant proportion of PNETs may not be visualized on conventional imaging such as computed tomography, magnetic resonance imaging, and somatostatin receptor scintigraphy. Endoscopic ultrasound (EUS) has become an integral part of the diagnosis of PNETs because of its high sensitivity for detecting, localizing, and diagnosing PNETs. EUS-guided tissue acquisition provides histologic and immunologic confirmation, and may also allow prognostication about tumor behavior. In addition to preoperative assessment of these tumors, EUS has also been shown to have an important role in nonoperative management of small nonfunctional PNETs. Finally, recent developments suggest that interventional EUS may be used to aid intraoperative localization of PNETs and to deliver therapeutic agents for the treatment of PNETs. This review will discuss the endoscopic diagnosis and treatment of PNETs, with focus on recent advances in the utility of EUS in the clinical management of these tumors.

Pancreatic neuroendocrine tumor accompanied with multiple liver metastases

Pancreatic neuroendocrine tumor (P-NET) is rare and slow-growing. Current classifications predict its prognosis and postoperative recurrence. Curative resection is ideal, although often difficult, because over 80% of patients have unresectable multiple liver metastases and extrahepatic metastasis. Aggressive surgery for liver metastases is important to improve survival. Aggressive or cytoreductive surgery for liver metastases is indicated to reduce hormone levels and improve symptoms and prognosis. Liver transplantation was originally conceived as an ideal therapy for unresectable liver metastases. Unfortunately, there is no clear consensus on the role and timing of surgery for primary tumor and liver metastases. Surgeons still face questions in deciding the best surgical scenario in patients with P-NET with unresectable liver metastases.

Endoscopic ultrasound and pancreatic applications: what the radiologist needs to know

As the technology has improved, endoscopic ultrasound (EUS) has taken on an important role in the diagnosis of a number of different neoplastic and non-neoplastic pancreatic diseases. EUS can provide high-resolution images with subtle anatomic detail, and has also taken on an important role in the targeted biopsy of the pancreas and adjacent structures. This review seeks to familiarize radiologists with the role of EUS in the diagnosis of chronic and autoimmune pancreatitis, solid pancreatic masses, and cystic pancreatic neoplasms.

Performance of endoscopic ultrasound-guided fine needle aspiration in diagnosing pancreatic neuroendocrine tumors

Background:

Pancreatic neuroendocrine tumors (PNETs) are rare tumors of the pancreas, which are increasingly diagnosed by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). In this retrospective study, we assessed the performance of EUS-FNA in diagnosing PNETs.

Materials and Methods:

We identified 48 cases of surgically resected PNETs in which pre-operative EUS-FNA was performed. The clinical features, cytological diagnoses, and surgical follow-up were retrospectively reviewed. The diagnostic performance of EUS-FNA was analyzed as compared to the diagnosis in the follow-up. The cases with discrepancies between cytological diagnosis and surgical follow-up were analyzed and diagnostic pitfalls in discrepant cases were discussed.

Results:

The patients were 20 male and 28 female with ages ranging from 15 years to 81 years (mean 57 years). The tumors were solid and cystic in 41 and 7 cases, respectively, with sizes ranging from 0.5 cm to 11 cm (mean 2.7 cm). Based on cytomorphologic features and adjunct immunocytochemistry results, when performed, 38 patients (79%) were diagnosed with PNET, while a diagnosis of suspicious for PNET or a diagnosis of neoplasm with differential diagnosis including PNET was rendered in the 3 patients (6%). One case was diagnosed as mucinous cystic neoplasm (2%). The remaining 6 patients (13%) had non-diagnostic, negative or atypical diagnosis.

Conclusions:

Our data demonstrated that EUS-FNA has a relatively high sensitivity for diagnosing PNETs. Lack of additional materials for immunocytochemical studies could lead to a less definite diagnosis. Non-diagnostic or false negative FNA diagnosis can be seen in a limited number of cases, especially in those small sized tumors.

Pancreatic neuroendocrine tumor with cystlike changes: evaluation with MDCT

OBJECTIVE

The objective of our study was to determine the prevalence and CT appearance of cystlike changes of pancreatic neuroendocrine tumor (NET), particularly of small (≤ 3 cm) tumors.

MATERIALS AND METHODS

The clinical records, images, and pathologic reports of 74 consecutive patients (average age, 55.5 years) with surgically resected pancreatic NETs who underwent preoperative CT were retrospectively reviewed. The size and location of the pancreatic NETs were recorded. The tumors were classified on the basis of CT appearance as small (≤ 3 cm) or large (> 3 cm) and as solid, partially (≤ 50% or > 50%) cystic, or purely (≈ 100%) cystic. Peripheral contrast enhancement on CT was characterized, and lymph node and liver metastases found by pathologic examination were recorded.

RESULTS

A total of 78 pancreatic NETs were reviewed. Five were not visualized on CT, leaving 73 pancreatic NETs in 69 patients (multiple tumors were visualized on CT of three patients) for analysis. The mean size of the 73 tumors was 3.0 ± 2.6 (SD) cm (range, 0.7-13.1 cm); 52 tumors were 3 cm or smaller and 21 tumors were larger than 3 cm. Gross pathologic results confirmed that 13 of the 73 (17.8%) tumors were predominantly (> 50% or ≈ 100%) cystic: 10 of the 52 (19.2%) tumors 3 cm or smaller and three of the 21 (14.3%) tumors larger than 3 cm. Peripheral contrast enhancement was seen in 11 of the 13 (85%) predominantly cystic pancreatic NETs. Compared with solid pancreatic NETs, predominantly cystic pancreatic NETs were less commonly associated with lymph node and liver metastases.

CONCLUSION

Cystic pancreatic NETs are not rare and should be included in the differential diagnosis of a cystic pancreatic mass, particularly if the cystic mass is associated with peripheral contrast enhancement. A minority of cystic pancreatic NETs can present with no peripheral enhancement.

Magnetic resonance imaging versus endoscopic ultrasonography for the detection of pancreatic tumours in multiple endocrine neoplasia type 1

OBJECTIVE

In multiple endocrine neoplasia type 1, the main risk factor for metastases is pancreatic tumour size. We and others recommend limiting surgery to non-functioning pancreatic tumors ≥20 mm or growing, based on their size measured with endoscopic ultrasonography. Because endoscopic ultrasonography is invasive, we compared endoscopic ultrasonography (EUS) to non-invasive magnetic resonance imaging (MRI) for the detection of pancreatic tumours ≥10 mm in multiple endocrine neoplasia type 1 patients.

METHODS

A prospective study was performed in nine participating centres; 90 patients with multiple endocrine neoplasia type 1 underwent EUS and MRI with gadolinium infusion. Gastroenterologists and radiologists were blinded to the results, magnetic resonance images were reviewed centrally.

RESULTS

EUS detected 86 tumours ≥10 mm, and 48 (53.3%) patients had at least one tumour ≥10 mm. MRI detected 67 tumours ≥10 mm, and 46 (51.1%) patients had at least one tumour ≥10 mm. EUS and MRI agreement was moderate for detection of tumours ≥10 mm (Kappa coefficient=0.49), and for selection of patients with tumours ≥10 mm (Kappa coefficient=0.55). EUS and MRI missed 11/24 and 4/24 lesions ≥20 mm, respectively. EUS failed to identify 9/57 (15.7%) patients with pancreatic tumours ≥10 mm, and MRI failed to identify 11/57 (19.3%) patients with pancreatic tumours ≥10 mm.

CONCLUSIONS

EUS and MRI are complementary and should be performed at initial evaluation in multiple endocrine neoplasia type 1 patients. Whether follow-up should be based on either technique or both, requires further evaluation.

[Diagnostic endoscopic ultrasonography in the gastrointestinal tract]

Endoscopic ultrasonography is a relatively new technology that combines the use of flexible fiberoptic endoscopes with high-resolution ultrasound technology. It proved to be highly accurate and useful in the staging of gastrointestinal malignancies, as well as in characterizing the nature of subepithelial lesions and disorders of the pancreaticobiliary system. In this overview the variety of current evidence based diagnostic options of endoscopic ultrasonography are discussed.

EUS is still superior to multidetector computerized tomography for detection of pancreatic neuroendocrine tumors

BACKGROUND

The role of EUS for detection of pancreatic neuroendocrine tumors (PNETs) is not clearly defined in institutions that use multidetector CT for pancreatic imaging.

OBJECTIVE

The aims of this study were to (1) compare the detection rates of EUS and CT by type and size of PNET and calculate the incremental benefit of EUS over CT, (2) evaluate the CT detection rate for PNETs adjusted for improved CT technology over time, and (3) determine the factors associated with CT-negative PNETs.

DESIGN

Retrospective single-center cohort study.

SETTING

Johns Hopkins Hospital.

PATIENTS

Patients with pathologically proven PNETs with preoperative CT. Incidentally found PNETs (resection specimens) and those without Johns Hopkins Hospital CT imaging were excluded.

MAIN OUTCOME MEASUREMENT

Detection rates of CT and EUS were compared by using pathology as the reference standard.

RESULTS

In 217 patients (with 231 PNETs) studied, CT detected 84% of tumors (54.3% of insulinomas). The sensitivity of CT for the detection of PNETs significantly increased with improvement in CT technology (P = .02; χ(2) for trend). CT was more likely to miss lesions <2 cm (P = .005) and insulinomas (P < .0001). In 56 patients who had both CT and EUS, the sensitivity of EUS was greater than CT (91.7% vs 63.3%; P = .0002), particularly for insulinomas (84.2% vs 31.6%; P = .001). EUS detected 20 of 22 CT-negative tumors (91%).

LIMITATIONS

Retrospective nonrandomized design and referral bias.

CONCLUSIONS

The detection rate of CT has significantly improved over time. CT-negative tumors are small and more likely to be insulinomas. A sequential approach of CT followed by EUS can detect most PNETs. EUS is a more sensitive initial test for the detection of suspected insulinomas.

[Contribution of endoscopic ultrasonography to the diagnosis of neuroendocrine pancreatic tumors]

Neuroendocrine pancreatic tumors (NEPT) are relatively infrequent tumors, with an incidence of approximately 1 case per 100.000 inhabitants, representing only 1-2% of pancreatic neoplasms. Localization and staging of NEPT prior to surgery is essential to allow treatment optimization. However, localizing these tumors is often difficult, mainly because of their small size. On ultrasound, NEPT usually appear as rounded, hypoechoic and homogeneous lesions, with precise limits and peripheral enhancement due to their significant vascularization. The most precise technique for the diagnosis and localization of NEPT is endoscopic ultrasound (EUS), with a sensitivity and specificity as high as 95%, clearly superior to those of other imaging procedures. Overall diagnostic accuracy may even be increased by associating EUS-guided fine-needle aspiration.

Gastrointestinal neuroendocrine (carcinoid) tumours: current diagnosis and management

Neuroendocrine tumours (NETs) are increasing in both incidence and prevalence and, as a group, are more prevalent than either gastric, pancreatic, oesophageal or hepatobiliary adenocarcinomas, or any two of these cancers combined. Clinical awareness of the protean and intermittent symptoms of NETs (eg, sweating, flushing, diarrhoea, and bronchospasm) is critical for timely diagnosis; however, the classical carcinoid syndrome is relatively uncommon. The most useful diagnostic test for gastrointestinal NETs is measurement of plasma chromogranin A (CgA) levels. Disease extent is assessed by both anatomical imaging, and nuclear imaging with radiolabelled somatostatin analogues. Pathological evaluation comprises tumour-node-metastasis classification, a minimum pathological dataset, CgA and synaptophysin immunostaining, as well as mitotic count or Ki-67 index (a marker of cell proliferation) to define grading. Resection of the primary lesion and as much metastatic disease as possible increases the efficacy of medical therapy. Other management strategies include hepatic embolisation and peptide receptor radionuclide therapy. Patients with tumours expressing somatostatin receptors should be treated with somatostatin analogues. Depending on the tumour grade, other effective agents include cytotoxics, tyrosine kinase inhibitors, and antiangiogenics. The overarching requirement for best management of patients with NETs is to ensure that they have ready access to experienced multidisciplinary clinician groups located within centres of appropriate subspecialty expertise.

Contrast enhanced endoscopic ultrasound: More than just a fancy Doppler

Contrast enhanced endoscopic ultrasound (CEUS) is a new modality that takes advantage of vascular structure and blood flow to distinguish different clinical entities. Contrast agents are microbubbles that oscillate when exposed to ultrasonographic waves resulting in characteristic acoustic signals that are then converted to colour images. This permits exquisite imaging of macro- and microvasculature, providing information to help delineate malignant from non-malignant processes. The use of CEUS may significantly increase the sensitivity and specificity over conventional endoscopic ultrasound. Currently available contrast agents are safe, with infrequent adverse effects. This review summarizes the theory and technique behind CEUS and the current and future clinical applications.