Cystic pancreatic neuroendocrine tumors: endoscopic ultrasound and fine-needle aspiration characteristics.

BACKGROUND AND STUDY AIMS: Limited data are available on the endoscopic ultrasound (EUS) and fine-needle aspiration (FNA) characteristics of cystic pancreatic neuroendocrine tumors (CPanNets). The aims of this study were to describe the EUS and FNA characteristics of pathologically confirmed CPanNets and to compare these characteristics with mucinous cysts from matched patients. PATIENTS AND METHODS: From an EUS - FNA database (between 1999 and 2011), 19 patients with a pathologically confirmed CPanNet were identified. Patient characteristics, cyst fluid carcinoembryonic antigen (CEA) levels, pathology, and EUS findings were analyzed. For comparison, age- and sex-matched patients with mucinous cysts were randomly chosen from the same database. RESULTS: Of the 19 patients, two had multiple endocrine neoplasia type 1 and two had metastases. The median diameter of the lesions was 24 mm. EUS revealed unilocular lesions in 7 patients, thinly septated lesions with thin walls in 1, and mixed solid-cystic lesions in 11. EUS - FNA cytology confirmed neoplasm in 12 of the 19 patients (63.2 %). The median cyst fluid CEA level (n = 15) was 1.1 ng/mL (range 0.3 - 500 ng/mL). Compared with matched patients with mucinous cysts, the median cyst fluid CEA was lower (1.1 ng/mL vs. 400 ng/mL), thick walls were more common (66.7 % vs. 13.3 %), and diagnostic cytology was more likely (73.3 % vs. 20.0 %). CONCLUSIONS: Analysis of EUS and FNA results showed that the cyst fluid from CPanNets had a lower CEA concentration, a higher frequency of thick walls on EUS, and higher diagnostic cytology compared with mucinous cysts. These findings may aid in the diagnosis of CPanNets.

64-Slice multidetector row CT angiography of the abdomen: comparison of low versus high concentration iodinated contrast media in a porcine model.

OBJECTIVE: In this study we aimed to assess the image quality and degree of vascular enhancement using low-concentration contrast media (LCCM) (300 mg I ml(-1)) and high-concentration contrast media (HCCM) (370 mg I ml(-1)) on 64-slice multidetector row CT (MDCT) abdominal CT angiography (CTA). In addition, we aimed to study the feasibility of using HCCM with a reduced total iodine dose. METHODS: CTA of the abdomen on a 64-slice MDCT was performed on 15 anaesthetised pigs. Study pigs were divided into three groups of five each based on the iodine concentration and dose received: Group A (LCCM; 300 mg I ml(-1)), Group B (HCCM; 370 mg I ml(-1)) and Group C HCCM with 20% less iodine dose. The total iodine injected was kept constant (600 mg kg(-1)) in Groups A and B. Qualitative and quantitative analyses were performed to study and compare each group for image quality, visibility of the branch order of the superior mesenteric artery (SMA), artefacts, degree of enhancement in the aorta and main stem arteries and uniformity of enhancement in the aorta. Groups were compared using the analysis of variance test. RESULTS: The image quality of 64-slice MDCT angiography was excellent with a mean score of 4.63 and confident visualisation of the third to fifth order branches of the SMA in all groups. Group B demonstrated superior vascular enhancement, as compared with Groups A and C (p≤0.05). Uniform aortic enhancement was achieved with the use of LCCM and HCCM with 20% less iodine dose. CONCLUSION: 64-slice MDCT angiography of the abdomen was of excellent quality. HCCM improves contrast enhancement and overall CTA image quality and allows the iodine dose to be reduced.

Pancreatic cystic lesions: clinical predictors of malignancy in patients undergoing surgery.

BACKGROUND: Despite advances in cross-sectional imaging and the use of molecular markers, distinguishing between benign and malignant cysts remains a clinical challenge. AIMS: To identify both preoperative clinical and cyst characteristics at the time of EUS that predict malignancy. METHODS: A retrospective analysis was performed on consecutive patients with pancreatic cysts who underwent endoscopic ultrasound (EUS) and surgical resection from May 1996 to December 2007 at a tertiary centre. Clinical history, EUS characteristics, cytology, tumour markers and surgical histology were collected. Predictors of malignancy were determined by univariate and multivariate analysis using logistic regression. RESULTS: A total of 153 patients underwent a EUS and subsequent surgical intervention.Of the 153 patients, 57 (37%) had a histological diagnosis of malignancy. On univariate analysis, older age (P < 0.001), male gender (P = 0.010), jaundice (P = 0.039), history of other malignancy (P = 0.036), associated mass in cyst (P = 0.004) and malignant cytology (P < 0.001) were found to be associated with malignancy. History of pancreatitis (P = 0.008) and endoscopist impression of pseudocyst (P = 0.001) were found to be associated with benign cysts. Multivariate analysis found that only older age [Odds ratio (OR), 1.04; 95% confidence interval (CI), 1.01-1.08], male gender (OR, 2.26; 95% CI, 1.08-4.73) and malignant cytology (OR, 6.60; 95% CI, 2.02-21.58) were independent predictors of malignancy. CONCLUSIONS: Older age, male gender and malignant cytology from EUS predict malignancy at surgical resection. These characteristics may be used to estimate the probability of malignancy in a cyst and aid in management.

Management and outcomes of pancreatic cystic lesions.

The management of pancreatic cystic lesions offers a challenge to clinicians. Mucinous cystic lesions pose a low risk of the development of neoplasia that must be taken into account in long-term management. Although the natural history has not been well defined, it is likely that malignant change in the mucinous epithelium takes place over years, very similar to what is observed with Barrett's esophagus. The traditional therapy of mucinous cystic lesions has been surgical resection. Lesions in the head of the pancreas will require a Whipple resection whereas tail lesions are managed with a distal pancreatectomy and splenectomy. In patients at high risk for surgical resection, the risk/benefit ratio may be excessively high, not supporting the use of resection therapy. Ethanol ablation therapy has been thoroughly studied in hepatic, renal, and thyroid cysts. Epithelial ablation with ethanol appears to be highly effective and relatively safe. Recently, ethanol ablation has been evaluated in pancreatic cystic neoplasms. In macrocystic lesions between 1 and 5 cm, ethanol lavage will result in epithelial ablation and cyst resolution in a high percentage of patients. Pancreatitis is rarely observed clinically and is not present in resection specimens. A randomised prospective clinical trial is currently underway.

Natural orifice transesophageal mediastinoscopy and thoracoscopy.

BACKGROUND: Thoracoscopy and mediastinoscopy are common procedures with painful incisions and prominent scars. A natural orifice transesophageal endoscopic surgical (NOTES) approach could reduce pain, eliminate intercostal neuralgia, provide access to the posterior mediastinal compartment, and improve cosmesis. In addition NOTES esophageal access routes also have the potential to replace conventional thoracoscopic approaches for medial or hilar lesions. METHODS: Five healthy Yorkshire swine underwent nonsurvival natural orifice transesophageal mediastinoscopy and thoracoscopy under general anesthesia. An 8- to 9.8-mm video endoscope was introduced into the esophagus, and a 10-cm submucosal tunnel was created with blunt dissection. The endoscope then was passed through the muscular layers of the esophagus into the mediastinal space. The mediastinal compartment, pleura, lung, mediastinal lymph nodes, thoracic duct, vagus nerves, and exterior surface of the esophagus were identified. Mediastinal lymph node resection was easily accomplished. For thoracoscopy, a small incision was created through the pleura, and the endoscope was introduced into the thoracic cavity. The lung, chest wall, pleura, pericardium, and diaphragmatic surface were identified. Pleural biopsies were obtained with endoscopic forceps. The endoscope was withdrawn and the procedure terminated. RESULTS: Mediastinal and thoracic structures could be identified without difficulty via a transesophageal approach. Lymph node resection was easily accomplished. Pleural biopsy under direct visualization was feasible. Selective mainstem bronchus intubation and collapse of the ipsilateral lung facilitated thoracoscopy. In one animal, an inadvertent 4-mm lung incision resulted in a pneumothorax. This was decompressed with a small venting intercostal incision, and the remainder of the procedure was completed without difficulty. CONCLUSIONS: Transesophageal endoscopic mediastinoscopy, lymph node resection, thoracoscopy, and pleural biopsy are feasible and provide excellent visualization of mediastinal and intrathoracic structures. Survival studies will be needed to confirm the safety of this approach.

Single-operator duodenoscope-assisted cholangioscopy is an effective alternative in the management of choledocholithiasis not removed by conventional methods, including mechanical lithotripsy.

BACKGROUND AND STUDY AIMS: The widespread use of cholangioscopy in the management of difficult choledocholithiasis has been limited by the need for two expert operators. This report describes the use of a technique of single-operator duodenoscope-assisted cholangioscopy (SODAC) in the successful management of 75 patients with choledocholithiasis. PATIENTS AND METHODS: The single-operator technique, allowing simultaneous control of both the duodenoscope and cholangioscope, was prospectively studied between June 1999 and June 2001 in the diagnosis and treatment of choledocholithiasis. RESULTS: A total of 109 SODAC procedures were conducted in 75 patients to manage choledocholithiasis. The indications were: firstly, SODAC-guided electrohydraulic lithotripsy (EHL) of stones in which conventional methods, including mechanical lithotripsy, had not been successful (52 SODAC procedures in 26 patients); and secondly, direct visualization of the biliary tree after cholangiography to assess the presence of stones (57 SODAC procedures in 49 patients). The locations and numbers of the stones, but not their size, were predictive of the number of SODAC-guided lithotripsy sessions required. All of the patients were free of stones at the end of the study period, and no complications were recorded. CONCLUSIONS: Single-operator SODAC-guided electrohydraulic lithotripsy was effective in the treatment of difficult cases of choledocholithiasis in which conventional methods had previously failed. The technique may allow increased use of cholangioscopy in the management of choledocholithiasis.

Feasibility of endoscopic ultrasound-guided portal vein embolization with Enteryx.

BACKGROUND: Portal vein embolization (PVE) has been used as a preoperative strategy to induce hepatic lobar atrophy and contralateral lobe hypertrophy. We determined the feasibility of endoscopic ultrasound (EUS)-guided Enteryx (EVAL/ethylene-vinyl alcohol copolymer) embolization of the portal vein (EUS-PVE) in an animal model as a potential, minimally invasive, endoscopic technique. METHODS: EUS-guided embolization of the portal vein (EUS-PVE) using Enteryx was performed in a Yorkshire breed swine. Portal pressure measurements were obtained before and after vascular embolization. The animal was carefully monitored for seven days for evidence of abdominal pain, shock, or bleeding. An upper abdominal contrast-CT scan was performed to verify the location of the embolus. RESULTS: The PV pressure increased from 3 mmHg at baseline to a mean of 15 mmHg after EUS-PVE. The CT-scan on day 4 demonstrated Enteryx in the main portal vein with extension into the left branch. At sacrifice on day 7, a solid thrombus was visible grossly and histologically inside the main portal vein and the left branch of the portal vein. CONCLUSIONS: Selective embolization of the portal vein by EUS guidance appears to be feasible and a potential, minimally invasive, preoperative treatment option for patients undergoing extensive hepatectomy.

Detection and tumor staging of malignancy in cystic, intraductal, and solid tumors of the pancreas by EUS.

BACKGROUND: EUS can provide detailed imaging of pancreatic malignancies and direct fine needle aspiration (FNA) of pancreatic masses. The ability of EUS to detect and stage malignancy in cystic and intraductal lesions has not been investigated. Our aim was to determine the sensitivity and specificity of EUS imaging and FNA in detecting and staging of malignancy in solid, cystic, and intraductal lesions of the pancreas. METHODS: The records of 96 patients (46 solid, 26 cystic, 24 intraductal lesions) who underwent EUS followed by surgical exploration over a 3-year period were reviewed. The accuracy of EUS for detecting and staging malignancy was calculated based on the results of surgery and histology. RESULTS: EUS-guided FNA provided evidence of malignancy in solid, cystic, and ductal lesions with sensitivities of 59.5%, 50%, and 60%, respectively. The accuracy of staging by EUS was significantly less for intraductal lesions (47%), compared with cystic (100%) and solid lesions (85%) (p < 0. 05). CONCLUSIONS: EUS can be used to detect malignancy in cystic and intraductal tumors of the pancreas.

EUS diagnosis of cystic lesions of the pancreas.

BACKGROUND: Cystic tumors of the pancreas are composed of benign, premalignant, malignant, and inflammatory lesions that are traditionally difficult to diagnose. Most of the tumors are initially detected on CT/US scanning, but often the morphological characteristics are insufficient for making a definitive diagnosis. Endoscopic ultrasound (EUS) may be an ideal tool for imaging of these lesions because it can provide highly detailed imaging without interference by bowel or air. Furthermore, EUS can direct fine needle aspiration of the lesions, providing cyst fluid for cytologic examination. The findings of cyst fluid cytology can be complemented by the use of cyst fluid tumor makers such as CEA. Using the morphologic appearance by endosonography, the results of cytology, and tumor marker analysis, EUS can often differentiate between benign, malignant, and inflammatory cystic lesions of the pancreas.

Role of endoscopic ultrasound in the diagnosis of cystic lesions of the pancreas.

Endoscopic ultrasound (EUS) is an ideal imaging technique for pancreatic cystic lesions. Ultrasound is exquisitely sensitive for detecting and characterizing cysts arising in solid organs, and when the transducer is placed on an endoscope, high resolution imaging of the pancreas is achieved. Linear EUS can also guide needle aspiration of pancreatic cystic lesions and through the use of aspiration cytology, cystic tumors of the pancreas can be diagnosed. Since cytology is a relatively insensitive test, cyst fluid tumor markers such as CEA have been employed to improve the sensitivity for the detection of malignancy. Cyst fluid CEA values are uniformly low in serous cystadenomas, higher in mucinous lesions, and markedly elevated in mucinous cystadenocarcinomas. Through the use of these techniques, the ability to detect and diagnose early malignancies of the pancreas will be greatly enhanced.

EUS-guided radiofrequency ablation in the pancreas: results in a porcine model.

BACKGROUND: Our aim in this study was to investigate the feasibility and safety of performing radiofrequency (RF) ablation in the pancreas with endoscopic ultrasound (EUS). METHODS: RF was applied to normal pancreatic tissue in 13 anesthetized Yorkshire pigs with specially modified 19-gauge needle electrodes (1.0 to 1.5 cm tip). The pancreas was localized with EUS and punctured through a transgastric approach. RF current (285 +/- 120 mA) was delivered for 6 minutes. Diagnostic imaging (EUS and CT) and serum amylase and lipase levels were obtained at baseline, immediately after ablation, and 1 to 14 days after the procedure. Pigs were killed immediately (n = 5), 1 to 2 days after ablation (n = 2), and 2 weeks after the procedure (n = 6). Pathologic examination was performed. RESULTS: Sixteen ablations were performed. During ablation, round hyperechoic foci (diameter to 1.0 cm) gradually surrounded the tip of the electrode. Immediately after the procedure CT demonstrated 1 cm hypodense foci that did not enhance with iodinated contrast. In pigs killed immediately and 1 to 2 days after ablation, pathologic examination showed discrete, well-demarcated spherical foci of coagulation necrosis measuring 8 to 12 mm in diameter surrounded by a 1 to 2 mm rim of hemorrhage. Radiologic-pathologic correlation was within 2 mm. In 4 of 6 (67%) pigs killed on day 14, retraction of the coagulated focus was observed. A 1 to 3 mm fibrotic capsule surrounded the coagulated tissue in the remaining 2 pigs. One pig had mild hyperlipasemia, a focal zone of pancreatitis (<1 cm), and later a pancreatic fluid collection. Biochemical parameters were normal in the remaining pigs. Other complications included three gastric and one intestinal burn caused by improper electrode placement. CONCLUSIONS: EUS-guided RF ablation can be used safely to produce discrete zones of coagulation necrosis in the porcine pancreas. Potential clinical uses of this technology include management of small neuroendocrine tumors and possibly palliation of unresectable pancreatic adenocarcinoma.