Diagnosis of pancreatic tumors by endoscopic ultrasonography

Role of contrast-enhanced harmonic endoscopic ultrasonography (EUS) and EUS elastography in pancreatic lesions

Pancreatic cancers have a poor prognosis, and their incident rates have risen. Endoscopic ultrasonography (EUS) is an efficient and reliable diagnostic modality for pancreatic lesions, providing high spatial resolution. However, while EUS helps to detect minor pancreatic lesions, nearly all solid pancreatic lesions are hypoechoic, which creates difficulty in making differential diagnoses of pancreatic lesions. When diagnosing pancreatic lesions, the performance of image-enhanced EUS techniques is essential, such as EUS elastography or contrast-enhanced harmonic EUS (CH-EUS). CH-EUS diagnosis is based on assessing the vascularity of lesions, whereas tissue elasticity is measured via EUS elastography. Elastography is either strain or shear-wave, depending on the different mechanical properties being evaluated. The usefulness of enhanced EUS techniques is demonstrated in this review for the differential diagnosis of pancreatic lesions, including solid and cystic lesions, and pancreatic cancer staging.

Maintaining early diagnosis of pancreatic adenocarcinoma in Japan: Local resilience against COVID-19

BACKGROUND AND AIMS

This study evaluated the impact of the coronavirus disease 2019 (COVID-19) pandemic on pancreatic adenocarcinoma (PA) practice in our region and discussed the effects of our institution's regional collaborative system, the "Early Stage Pancreatic Cancer Diagnosis Project," which was originally unrelated to this study's purpose.

METHODS

We retrospectively investigated 150 patients with PA at Yokohama Rosai Hospital by defining three time periods: before (C0), during the first year (C1), and during the second year (C2) of the COVID-19 pandemic.

RESULTS

Among the three periods (C0, C1, and C2), there were significantly less patients with stage I PA (14.0%, 0%, and 7.4%, p = 0.032) in C1, and significantly more patients with stage III PA (10.0%, 28.3%, and 9.3%, p = 0.014) in C1. The pandemic significantly prolonged the median durations from disease onset to patients' first visits (28, 49, and 14 days, p = 0.012). In contrast, there was no significant difference in the median durations from referral to first visit to our institution (4, 4, and 6 days, p = 0.391).

CONCLUSIONS

The pandemic advanced the stage of PA in our region. Although the pancreatic referral network remained functional during the pandemic, there were delays from disease onset to patients' first visit to healthcare providers, including clinics. While the pandemic caused temporary damage to PA practice, the routine regional collaboration provided by our institution's project allowed for early resilience. A notable limitation is that the impact of the pandemic on PA prognosis was not evaluated.

Intermittent endoscopic ultrasound guided fine-needle aspiration for the diagnosis of solid pancreatic lesions. Pilot study

Background and purpose of the study: endoscopic ultrasound guided fine-needle aspiration (EUS-FNA) is the method of choice for sampling pancreatic solid lesions. However, there is significant heterogeneity in terms of the technique used. Intermittent aspiration has not been evaluated in pancreatic solid lesions and could improve the diagnostic performance.

METHODS

Single-blind, non-inferiority pilot study. Patients with solid pancreatic lesions and indication for EUS-FNA were prospectively included. Patients were randomly assigned to intermittent (IS) or continuous (CS) suction techniques. Diagnostic performance, cellularity, blood contamination and number of passes required to reach diagnosis were evaluated.

MAIN RESULTS

33 patients were assigned to CS (16 patients) or IS (17 patients). Diagnostic performance was 87.5% for CS and 94.1% for IS (OR 2.29, 95%CI 0.19-27.99, p = 0.51). In the IS group samples had higher cellularity (OR 1.83, 95%CI 0.48-6.91, p = 0.37) and lower blood contamination (OR 0.38, 95%CI 0.09-1.54, p = 0.18). The number of passes required to reach diagnosis was 2.12 for CS and 1.94 for IS (p = 0.64). Liquid cytology was obtained in 73.3% of IS and 61.5% of CS (OR 1.72, 95%CI 0.35-8.50).

CONCLUSIONS

The IS technique was not inferior to CS in terms of diagnostic accuracy in the evaluation of pancreatic solid lesions, with a tendency to obtain higher cellularity, lower blood contamination and frequent presence of cell block.

New Imaging Techniques for Endoscopic Ultrasonography: Contrast-Enhanced Endoscopic Ultrasonography

Conventional endoscopic ultrasonography (EUS) has limitations in the diagnosis of solid masses. Because most are depicted as a hypoechoic mass, without cytology or biopsy, it can be difficult to distinguish inflammatory masses from malignancy. Recently developed, contrast-enhanced harmonic EUS (CH-EUS) has improved characterization of digestive lesions by depicting microvessels and parenchymal perfusion, particularly for differentiating pancreatic cancer from other pancreatic solid lesions, identifying mural nodules in intraductal papillary mucinous neoplasms, and estimating malignant potential of gastrointestinal stromal tumors. CH-EUS is complementary to EUS-guided fine-needle aspiration for diagnosing pancreatic lesions, staging, and predicting chemotherapy response.

Impact of endoscopic ultrasonography (EUS) and EUS-guided fine-needle aspiration on the management of pancreatic cystic lesions

BACKGROUND AND STUDY AIMS

Endoscopic ultrasonography (EUS) and EUS-guided fine-needle aspiration (EUS-FNA) are well-recognized techniques for the study of pancreatic cystic lesions (PCLs). However, little evidence exists on their impact on clinical care. The aim of this study is to determine how often EUS and EUS-FNA alter the diagnosis and management of patients with PCLs.

PATIENTS AND METHODS

Eight physicians expert in pancreatic diseases were asked to report their diagnoses and management recommendations for 49 different PCLs. Clinical information was sequentially disclosed in a stepwise manner - progressively from clinical data plus computed tomography or MRI (level 1), to EUS (level 2) and EUS-FNA results including cytology, carcinoembryonic antigen, and amylase levels (level 3).

RESULTS

EUS led to a change in the diagnosis and management in 30% [95% confidence interval (CI): 26-35%] and 19% (95% CI: 16-23%) of cases, respectively, usually to a more intensive approach (14%; 95% CI: 11-18%). EUS-FNA altered the diagnosis and management in an additional 39% (95% CI: 34-44%) and 21% (95% CI: 17-25%) of the evaluations, respectively. EUS-FNA also increased the consensus in the diagnosis among the specialists that ranged from fair with computed tomography/MRI (κ-index=0.32) to substantial with EUS-FNA (κ-index=0.43).

CONCLUSION

EUS and EUS-FNA impact the diagnosis and management of patients with PCLs; therefore, both are necessary in the workup of these patients. EUS-FNA markedly improves the agreement between physicians in terms of diagnosis, but not management. This study highlights the need for more research and standardization in the field.

Evaluation of the Added Value of Diffusion-Weighted Imaging to Conventional Magnetic Resonance Imaging in Pancreatic Neuroendocrine Tumors and Comparison With 68Ga-DOTANOC Positron Emission Tomography/Computed Tomography

OBJECTIVES

The aims of this study were to investigate the added value of diffusion-weighted imaging (DWI) in pancreatic neuroendocrine tumor (pNET) evaluation and to compare magnetic resonance imaging (MRI) to Ga-DOTANOC positron emission tomography/computed tomography (PET/CT) results.

METHODS

Morphological MRI (T2-weighted [T2-w] + contrast-enhanced [CE] T1-w) and DWI (T2-w + DWI) and Ga-DOTANOC PET/CT in 25 patients/30 pNETs were retrospectively evaluated. Per-patient and per-lesion detection rates (pDR and lDR, respectively) were calculated. Apparent diffusion coefficient values were compared among pNET and surrounding and normal pancreas (control group, 18 patients). Apparent diffusion coefficient and standardized uptake value (SUV) values were compared among different grading and staging groups.

RESULTS

No statistically significant differences in PET/CT and MRI session detection rates were found (morphological MRI and DW-MRI, 88% pDR and 87% lDR; combined evaluation, 92% pDR and 90% lDR; Ga-DOTANOC PET/CT, 88% pDR and 80% lDR). Consensus reading (morphological/DW-MRI + PET/CT) improved pDR and lDR (100%). Apparent diffusion coefficient mean value was significantly lower compared with surrounding and normal parenchyma (P < 0.01). The apparent diffusion coefficient and SUV values of pNETs among different grading and staging groups were not statistically different.

CONCLUSIONS

Conventional MRI, DW-MRI + T2-w sequences, and Ga-DOTANOC PET/CT can be alternative tools in pNET detection. Diffusion-weighted MRI could be valuable in patients with clinical suspicion but negative conventional imaging findings. However, the consensus reading of the 3 techniques seems the best approach.

Endoscopic approach to the diagnosis of pancreatic cystic tumor

Because of the aging of the population, prevalence of medical checkups, and advances in imaging studies, the number of pancreatic cystic lesions detected has increased. Once these lesions are detected, neoplastic cysts should be differentiated from non-neoplastic cysts. Furthermore, because of the malignant potential of some neoplastic pancreatic cysts, further differentiation between benign and malignant cysts should be made regardless of their size. Although endoscopic ultrasound (EUS) has a very high diagnostic performance for pancreatic cystic lesions among the various imaging modalities, EUS findings alone are insufficient for the differentiation of pancreatic cysts and diagnosis of malignancy. In addition, cytology by EUS-guided fine-needle aspiration (FNA) has a high specificity but a low sensitivity for diagnosing malignancy in pancreatic cystic tumors. The levels of amylase, lipase, and tumor markers in pancreatic cystic fluid are considered auxiliary parameters for diagnosis of benign and malignant cysts, and a definitive diagnosis of malignancy using these parameters is difficult. Thus, in addition to EUS, cytology by EUS-FNA, and cystic fluid analysis, new techniques based on EUS-guided through-the-needle imaging, such as confocal laser endomicroscopy and cystoscopy, have been explored in recent years.

Contrast-Enhanced Endoscopic Ultrasonography for Pancreatic Tumors

OBJECTIVES

To investigate the usefulness of contrast-enhanced endoscopic ultrasonography (CE-EUS) for histological differentiation of pancreatic tumors.

METHODS

CE-EUS was performed for consecutive patients having a pancreatic solid lesion, and tumors were classified into three vascular patterns (hypervascular, isovascular, and hypovascular) at two time phases (early-phase and late-phase). Correlation between vascular patterns and histopathology of resected pancreatic cancer (PC) tissues was ascertained.

RESULTS

The final diagnoses of 147 examined tumors were PC (n = 109), inflammatory mass (n = 11), autoimmune pancreatitis (n = 9), neuroendocrine tumor (n = 8), and others (n = 10). In late-phase images, 104 of 109 PCs had the hypovascular pattern, for a diagnostic sensitivity and specificity of 94% and 71%, respectively. Of 28 resected PCs, 10 had isovascular, and 18 hypovascular, patterns on the early-phase image. Early-phase isovascular PCs were more likely to be differentiated than were early-phase hypovascular PCs (6 well and 4 moderately differentiated versus 3 well, 14 moderately, and 1 poorly differentiated, P = 0.028). Immunostaining revealed that hypovascular areas of early-phase images reflected heterogeneous tumor cells with fibrous tissue, necrosis, and few vessels.

CONCLUSION

CE-EUS could be useful for distinguishing PC from other solid pancreatic lesions and for histological differentiation of PCs.

Contrast-enhanced harmonic endoscopic ultrasound-guided fine-needle aspiration in the diagnosis of solid pancreatic lesions: a retrospective study

BACKGROUND

The negative predictive value of endoscopic ultrasonography-guided fine needle aspiration for the diagnosis of solid pancreatic lesions remains low, and the biopsy specimens are sometimes inadequate for appropriate pathological diagnosis.

AIMS

To evaluate the usefulness of a novel method of contrast-enhanced harmonic endoscopic ultrasonography-guided fine-needle aspiration for the differential diagnosis and adequate sampling of solid pancreatic lesions.

METHODS

Patients with a diagnosis of solid pancreatic lesions who underwent fine-needle aspiration guided by contrast-enhanced harmonic endoscopic ultrasonography or by endoscopic ultrasonography from October 2010 to July 2013 were retrospectively identified and classified into the CH-EUS or EUS group, respectively. Surgical pathology and/or follow-up results were defined as the final diagnosis. Operating characteristics and adequacy of biopsy specimens by fine-needle aspiration were compared between the two groups.

RESULTS

Operating characteristics for contrast-enhanced harmonic endoscopic ultrasonography-guided fine-needle aspiration in solid pancreatic lesions were as follows: area under the curve = 0.908, sensitivity = 81.6%, specificity = 100%, positive predictive value = 100%, negative predictive value = 74.1%, and accuracy = 87.9%. The percentage of adequate biopsy specimens in the CH-EUS group (96.6%) was greater than that in the EUS group (86.7%).

CONCLUSION

Simultaneous contrast-enhanced harmonic endoscopic ultrasonography during fine-needle aspiration is useful for improving the diagnostic yield and adequate sampling of solid pancreatic lesions.

Pancreatic cystic lesions: The value of contrast-enhanced endoscopic ultrasound to influence the clinical pathway

Background and Objectives:

Cystic pancreatic lesions are a growing diagnostic challenge. The aim of this study was to proof a new diagnostic concept based on contrast-enhanced endoscopic ultrasound (CE-EUS) for differential diagnosis.

Patients and Methods:

A total of 125 patients with unclear cystic pancreatic lesions were included. The initial diagnostic was made by CE-EUS dividing the lesions in a group without contrast enhancing effect in the cystic wall, septae or nodule indicating pseudocysts or dysontogenetic cysts and a group with contrast enhancing effect in the described structures indicating cystic neoplasias. The investigations were performed using a Pentax echoendoscope and Hitachi Preirus ultrasound machine. The contrast enhancer used was 4.8 mL SonoVue^® (Bracco, Italy). The group with suspected cystic neoplasia was referred for endoscopic fine-needle puncture for further diagnostic or treatment decisions.

Results:

The dividing of the groups by contrast-enhanced ultrasound was feasible because all (n = 56) suspected cystic neoplasias showed a contrast enhancing effect, whereas in only 4 from 69 pseudocystic or dysontogenetic cystic lesions a contrast enhancing effect in the wall could be observed. Endoscopic fine-needle puncture could diagnose all malignant neoplasias and relevant premalignant conditions. The long-term follow-up did not show any development of malignant cystic lesions.

Conclusion:

Using CE-EUS and endoscopic fine-needle puncture as diagnostic criteria seemed to be a feasible method to deal with different cystic lesions in daily practice.

Diagnosis and treatment of pancreatic pseudocysts and cystic tumors based on own material and quoted literature

Pseudocysts constitute the most basic cystic lesions of the pancreas. Symptomatic cysts may be treated by means of both minimally invasive methods and surgery. Currently, it is believed that approximately 5% of cystic lesions in the pancreas may in fact, be neoplastic cystic tumors. Their presence is manifested by generally irregular multilocular structures, solid nodules inside the cyst or in the pancreatic duct, frequently vascularized, as well as fragmentary thickening of the cystic wall or septation.

Clinical role of contrast-enhanced harmonic endoscopic ultrasound in differentiating solid lesions of the pancreas: a single-center experience in Korea

Background/Aims

The differential diagnosis of pancreatic solid lesions remains challenging. The aim of this study was to investigate the accuracy of contrast-enhanced harmonic endoscopic ultrasound (CEH-EUS) in differentiating pancreatic cancer from benign lesions.

Methods

We prospectively evaluated 37 patients with pancreatic solid lesions. After intravenous injection of a contrast agent (SonoVue), CEH-EUS was performed using a radial echoendoscope. Pancreatic solid lesions were classified into three vascular patterns (hyperintense, isointense, and hypointense) on the basis of CEH-EUS imaging, and these patterns were compared to the histological diagnosis.

Results

The lesions were hypervascular (n=6), isovascular (n=3), or hypovascular (n=28). Histological diagnosis was confirmed by EUS-FNA in 26 patients (22 adenocarcinomas, two focal pancreatitis, one pancreatic neuroendocrine tumor [NET], and one pancreatic tuberculosis); by surgery in 10 patients (four adenocarcinomas, three pancreatic NETs, two invasive intraductal papillary mucinous neoplasms, and one acinar cell carcinoma); and by both methods in one patient. Among pancreatic carcinomas, 28 out of 30 lesions (93%) had persistent hypovascular signals in the early and late phase, which indicates a sensitivity and diagnostic accuracy of 93% and 92%, respectively for the diagnosis of pancreatic cancer.

Conclusions

CEH-EUS was useful for characterization of pancreatic solid masses with high sensitivity and accuracy.

Clinical usefulness of plasma chromogranin a in pancreatic neuroendocrine neoplasm

Chromogranin A (CgA) is widely used as an immunohistochemical marker of neuroendocrine neoplasms and has been measurable in plasma of patients. We assessed the clinical role of plasma CgA in diagnosing pancreatic neuroendocrine neoplasm (PNEN). CgA was checked in 44 patients with pancreatic mass who underwent surgical resection from 2009 through 2011. The cutoff value for diagnosing PNEN and the relationships between CgA and clinicopathologic variables were analyzed. Twenty-six patients were PNENs and 18 patients were other pancreatic disorders. ROC analysis showed a cutoff of 60.7 ng/mL with 77% sensitivity and 56% specificity, and the area under the curve (AUC) was 0.679. Among PNEN group, the sensitivity and specificity of diagnosing metastasis were 100% and 90% respectively when CgA cutoff was 156.5 ng/mL. The AUC was 0.958. High Ki-67 index (160.8 vs 62.1 ng/mL, P = 0.001) and mitotic count (173.5 vs 74.6 ng/mL, P = 0.044) were significantly correlated with plasma CgA, but the tumor size was not. In conclusion, CgA has a little value in diagnosing PNEN. However, the high level of CgA (more than 156.5 ng/mL) can predict the metastasis. Also, plasma CgA level correlates with Ki-67 index and mitotic count which represents prognosis of PNENs.

MRI of the pancreas: problem solving tool

Advances in MR hardware and pulse sequence design over the years have improved the quality and robustness of MR imaging of the pancreas. Today, MRI is an indispensible tool for studying the pancreas and can provide useful information not attainable with other noninvasive or minimally invasive imaging techniques. In the present review, specific cases are reviewed where the strengths of MRI demonstrate the utility of this imaging modality as a problem solving tool.

Usefulness of contrast-enhanced endoscopic sonography for discriminating mural nodules from mucous clots in intraductal papillary mucinous neoplasms: a single-center prospective study

OBJECTIVES

The aim of this study was to evaluate the ability of contrast-enhanced endoscopic sonography for discrimination of mural nodules from mucous clots in intraductal papillary mucinous neoplasms of the pancreas.

METHODS

Contrast-enhanced endoscopic sonography was performed in 17 consecutive patients who had an intraductal papillary mucinous neoplasm with mural lesions. To perform contrast-enhanced endoscopic sonography, we used a second-generation sonographic contrast agent. After reconstitution with 2 mL of sterile water for injection, 0.7 mL of the agent was administered through a peripheral vein. From 10 to 30 seconds after injection of the contrast agent, the presence or absence of vascularity in mural lesions was assessed. All cases were referred to surgery, and diagnoses were finally obtained by pathologic examination. Diagnoses of mural nodules versus mucous clots based on the sonographic results were compared with tumor histopathologic findings.

RESULTS

Pathologic findings revealed 12 cases with mural nodules and 5 cases without. Contrast-enhanced endoscopic sonography depicted vascularity in all 12 cases with pathologically confirmed mural nodules, whereas all 4 cases without vascularity had mucous clots. Only 1 case without a pathologically confirmed mural nodule was overestimated by contrast-enhanced endoscopic sonography as having a mural nodule. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of contrast-enhanced endoscopic sonography for mural nodule detection were 100%, 80%, 92%, 100%, and 94%, respectively.

CONCLUSIONS

Evaluation of vascularity by contrast-enhanced endoscopic sonography could be useful for distinguishing mural nodules from mucous clots in intraductal papillary mucinous neoplasms. Contrast-enhanced endoscopic sonography could be a necessary option to determine surgical indications for intraductal papillary mucinous neoplasms when mural lesions are observed.

Contrast-enhanced harmonic endoscopic ultrasonography in pancreatic diseases

Endoscopic ultrasonography (EUS) is the most sensitive imaging method for diagnosis of pancreatic tumors. However, it still has limits in the differentiation between pancreatic cancers and inflammatory tumor-like masses. A novel technology, contrast-enhanced harmonic EUS (CH-EUS), has been developed recently. It can visualize both parenchymal perfusion and microvasculature in pancreas without Doppler-related artifacts. Therefore, it is superior to EUS and CT in detecting small pancreatic masses and differential diagnosis of pancreatic masses. CH-EUS could be used for adequate sampling of pancreatic tumors and may predict the pathological features of the pancreatic solid lesions but still cannot replace EUS-FNA now.

Contrast-enhanced endoscopic ultrasonography in digestive diseases

Contrast-enhanced endoscopic ultrasonography (CE-EUS) was introduced in the early 1990s. The concept of the injection of carbon dioxide microbubbles into the hepatic artery as a contrast material (enhanced ultrasonography) led to "endoscopic ultrasonographic angiography". After the arrival of the first-generation contrast agent, high-frequency (12 MHz) EUS brought about the enhancement of EUS images in the diagnosis of pancreatico-biliary diseases, upper gastrointestinal (GI) cancer, and submucosal tumors. The electronic scanning endosonoscope with both radial and linear probes enabled the use of high-end ultrasound machines and depicted the enhancement of both color/power Doppler flow-based imaging and harmonic-based imaging using second-generation contrast agents. Many reports have described the usefulness of the differential diagnosis of pancreatic diseases and other abdominal lesions. Quantitative evaluation of CE-EUS images was an objective method of diagnosis using the time-intensity curve (TIC), but it was limited to the region of interest. Recently developed Inflow Time Mapping™ can be generated from stored clips and used to display the pattern of signal enhancement with time after injection, offering temporal difference of contrast agents and improved tumor characterization. On the other hand, three-dimensional CE-EUS images added new information to the literature, but lacked positional information. Three-dimensional CE-EUS with accurate positional information is awaited. To date, most reports have been related to pancreatic lesions or lymph nodes. Hemodynamic analysis might be of use for diseases in other organs: upper GI cancer diagnosis, submucosal tumors, and biliary disorders, and it might also provide functional information. Studies of CE-EUS in diseases in many other organs will increase in the near future.

Differentiation between pancreatic carcinoma and mass-forming chronic pancreatitis: usefulness of high b value diffusion-weighted imaging

OBJECTIVE

To investigate the value of high b value diffusion-weighted (DW) imaging in differentiating between pancreatic carcinoma and mass-forming chronic pancreatitis (MFCP).

METHODS

Fifty-one consecutive patients with pathology-proven pancreatic carcinoma (n = 37) or MFCP (n = 14) were evaluated with DW imaging (b value, 0 and 1000 s/mm(2)) at a 3-T MR system. Overall 20 healthy volunteers were evaluated as the control group. The apparent diffusion coefficient (ADC) values of normal pancreas, pancreatic carcinoma, MFCP, and mass-associated obstructive pancreatitis were measured.

RESULTS

On high b value (1000 s/mm(2) ) DW images, both pancreatic carcinoma and MFCP were hyperintense focal lesions; mass-associated obstructive pancreatitis occurred in 17 of 37 (45.9%) pancreatic carcinoma and 8 of 14 (57.1%) MFCP. The ADC (×10(-3) mm(2) /s) of the pancreatic carcinomas (1.06 ± 0.15) was significantly lower than that of normal pancreas (1.47 ± 0.18; P < 0.01), MFCP (1.35 ± 0.14; P < 0.01) and mass-associated chronic pancreatitis (1.44 ± 0.17; P < 0.01). The ADC of MFCP was also lower than that in the normal pancreas (P = 0.025), whereas the ADC of mass-associated obstructive pancreatitis was not different from those of the MFCP (P = 0.113) and normal pancreas (P = 0.544). When 1.195 was used as the optimal cut-off value, ADC quantification obtained a sensitivity of 85.7% and a specificity of 86.5% for differentiating pancreatic carcinomas from MFCP.

CONCLUSION

High b value DW imaging in combination with ADC quantification at a 3-T MR system is useful in differentiating between pancreatic carcinoma and MFCP.

Recent advances in understanding pancreatic endocrine tumors

Pancreatic endocrine tumors (PETs) are uncommon and have an incidence of approximately 4-5 per 1 000 000 people, accounting for 1%-2% of all pancreatic neoplasms. They usually grow slowly, eventually metastasize and lead to death. PETs can be classified as functioning or non-functioning tumors based on clinical manifestation. The pathogenesis of PETs may involve abnormal expression of CD10, CD44, CD99, p27, COX2, Ki-67, KIT, CK19, ARHI, RUNX1T1, and survivin genes, loss of heterozygosity on chromosomes, hypermethylation of tumor suppressor genes, and overexpression of ghrelin. Chromogranin A (CgA) has long been used as an important broad-spectrum marker for the identification of PETs. KIT and endoglin are new independent prognostic markers for PETs. The diagnosis is based on histopathology demonstrating neuroendocrine features such as positive staining for chromogranin A and specific hormones such as gastrin, proinsulin, vasoactive intestinal peptide (VIP) and glucagon. In addition to standard localization procedures, radiology diagnosis including computed tomography (CT), positron emission tomography and computed tomography (PET/CT), magnetic resonance imaging (MRI), ultrasound (US), endoscopic ultrasound (EUS), laparoscopic ultrasound (LUS), dynamic enhanced spiral CT, selective arterial stimulation and venous sampling (ASVS), and somatostatin receptor scintigraphy (SRS) are performed. Surgery is still one of the cornerstones in the management of PETs. Laparoscopy, and drugs of somatostatin analogs are routinely used. Understanding of the recent advances of PETs has important implications for the early diagnosis and treatment of PETs.