Byoung Wook Bang

Effectiveness of contrast-enhanced harmonic endoscopic ultrasound for the evaluation of solid pancreatic masses

AIM To evaluate the usefulness of contrast-enhanced harmonic endoscopic ultrasound (CH-EUS) in differentiating between pancreatic adenocarcinomas and other pancreatic disease. METHODS This retrospective cohort study evaluated 90 patients who were seen between November 2010 and May 2013. All these patients had solid pancreatic masses that had a hypoechoic appearance on EUS. All patients underwent CH-EUS to evaluate this diagnostic methods usefulness. The mass lesions observed on CH-EUS were classified into three categories based on their echo intensity: hypoenhanced, isoenhanced, and hyperenhanced lesions. We adjusted the sensitivity and the specificity of each category for detecting malignancies. We also estimated the accuracy of CH-EUS by comparing it to a pathological diagnosis. RESULTS Of the 90 patients, 62 had a pancreatic adenocarcinoma. Fifty-seven out of 62 pancreatic adenocarcinomas showed a hypoenhanced pattern on CH-EUS. The sensitivity was 92%, the specificity 68% and the accuracy approximately 82%. The area under the curve of the receiver operating characteristic analysis for CH-EUS was 0.799. There is a significant association between the hypoenhanced pattern on CH-EUS and pancreatic duct adenocarcinoma (χ(2) = 35.264, P < 0.001). In pathological examinations, the number of specimens for EUS-fine needle aspiration (EUS-FNA) was considered insufficient for diagnosis in three patients, and in two patients, the results were reported to be negative for malignancy. Pancreatic masses in all five patients revealed a hypoenhanced pattern with CH-EUS. Three patients were diagnosed with pancreatic adenocarcinoma based on the pathology results of a biopsy, and the remaining two patients were clinically diagnosed with malignancy. CONCLUSION CH-EUS is useful for distinguishing between pancreatic adenocarcinoma and other pancreatic disease. When a pancreatic mass shows a hypoenhanced pattern on CH-EUS but involves either insufficient samples or negative results with EUS-FNA, clinicians might consider performing another pathologic diagnosis on the basis of an EUS-FNA sample or a biopsy.

Risk Factors for Long-term Outcomes after Initial Treatment in Hepatolithiasis

Hepatobiliary complications, such as stone recurrence, recurrent cholangitis, liver abscess, secondary biliary cirrhosis, and cholangiocarcinoma may occur after treatment for hepatolithiasis. However, few previous studies have addressed the risk factors and long-term outcomes after initial treatment. Eighty-five patients with newly diagnosed hepatolithiasis, actively treated for hepatolithiasis, constituted the cohort of this retrospective study. Patients were treated by hepatectomy or nonoperative percutaneous transhepatic cholangioscopic lithotomy. Long-term complications, such as recurrent cholangitis, liver abscess, secondary biliary cirrhosis, and cholangiocarcinoma, and their relationships with clinical parameters were analyzed. The mean follow-up period was 57.4 months. The overall hepatobiliary complication rate after the treatment was 17.6%. Multivariate analysis of suspected risk factors showed that complications were associated with age (HR, 1.046; CI, 1.006-1.089), bile duct stricture (HR, 4.894; CI, 1.295-18.495), and residual stones (HR, 3.482; CI, 1.214-9.981). In conclusion, several long-term hepatobiliary complications occur after hepatolithiasis treatment, and regular observation is necessary in patients with concomitant biliary stricture or residual stones.

Clinical advantages of a metal stent with an S-shaped anti-reflux valve in malignant biliary obstruction

Transpapillary stent insertion is the standard treatment for palliating malignant biliary obstruction. However, luminal occlusion often occurs due to sludge formation, tumor ingrowth, or tumor overgrowth. Currently, influx of duodenal contents by duodenobiliary reflux is considered a mechanism of stent obstruction. The aim of the present study was to evaluate the efficacy and safety of a metal stent with an anti‐reflux valve in distal malignant biliary obstruction.

Ten-day empirical sequential or concomitant therapy is more effective than triple therapy for Helicobacter pylori eradication: A multicenter, prospective study

BACKGROUND The resistance of Helicobacter pylori to antibiotics has increased the need for new empirical, first-line treatments. However, the efficacy of sequential therapy (ST) and concomitant therapy (CT) compared with triple therapy (TT) has not been adequately evaluated. AIM In this study, we evaluated the efficacy of these empirical three regimens. METHODS The 517 patients enrolled in the study were prospectively randomized to receive 10 days of TT (n=171), ST (n=170), and CT (n=176) at 5 university-affiliated hospitals from May 2013 to March 2015. The post-treatment H. pylori status was determined using the (13)C-urea breath test. RESULTS The baseline characteristics were similar among the three groups. The intention-to-treat eradication rates were 62.6%, 70.6%, and 77.8% in the TT, ST, and CT groups, respectively (p<0.01). The corresponding per-protocol eradication rates were 82.8%, 89.5%, and 94.4%, respectively (p<0.01). There were no significant differences in the compliance, side effects, and follow-up loss rates. CONCLUSION A higher eradication rate was achieved with empirical 10-day ST, and CT than with the TT regimen, with similar rates of compliance and treatment side effects.

Peroral Endoscopic Myotomy for Treating Achalasia in an Animal Model: A Feasibility Study

Background/Aims Laparoscopic Heller myotomy with antireflux procedure is considered to be a standard treatment for achalasia. Recently, peroral endoscopic myotomy (POEM) was developed and performed on patients with achalasia. However, there is no report on POEM use in South Korea. The aim of this study was to evaluate the technical feasibility of POEM in a porcine model. Methods POEM was performed on two mini pigs. We performed upper endoscopy under general anesthesia. A submucosal tunnel was created and the circular muscle layer was incised using several knives. The mucosal entry was closed using resolution clips. We performed a follow-up endoscopy and sacrificed the pigs 2 weeks after the POEM. The myotomy site was evaluated grossly and histologically. Results POEM was successfully performed on the two mini pigs. No injuries to any abdominal or mediastinal structures occurred. Two weeks after the POEM, the esophageal mucosa healed without any endoscopic evidence of complications. Necropsy revealed that the circular muscle layer was completely lost and replaced with fibrotic tissue. Conclusions We found that POEM is a technically feasible method which can be performed on an animal model. However, to ensure safe use on patients with achalasia, further studies on technical methods and long-term follow-up examinations are required.

Synchronous large-cell neuroendocrine carcinoma and adenocarcinoma of the colon.

Large-cell neuroendocrine carcinoma of the colon is a rare entity with a prognosis that is usually poor due to the high likelihood of early metastasis. A 61-year-old man had surgery for colon cancer of the transverse colon and cecum. Microscopic examination of the tumor showed that the location was the proximal transverse colon, with small nests containing rosettes and palisading patterns of large tumor cells with faintly granular cytoplasm. The immunohistochemistry was positive for synaptophysin and chromogranins. The tumors were diagnosed as a large-cell neuroendocrine carcinoma of the colon. In addition, the tumor of the cecum showed microscopic findings consistent with a well-differentiated adenocarcinoma. The immunohistochemical panel showed that the tumor was negative for neuroendocrine markers. There were no clinical findings suggestive of hormone hypersecretion. Cancer metastasis was found in the peritoneum section of the small bowel. Postoperative chemotherapy was applied. The patient was alive with good performance after, and there was no sign of tumor progression. This is the first case of a synchronous large-cell neuroendocrine carcinoma and adenocarcinoma of the colon. The patient was treated successfully with debulking surgery and systemic chemotherapy.

A Case of Esophageal Fibrovascular Polyp That Induced Asphyxia during Sleep

Esophageal fibrovascular polyps are rare, benign, submucosal tumors of the upper digestive tract that usually have an indolent course until the lesion attains a very large size. The most frequent complaints associated with these tumors include dysphagia and foreign body sensation. However, a long pedunculated polyp can regurgitate into the pharynx or oral cavity and cause asphyxia and sudden death if the larynx is occluded. We describe the case of a 51-year-old man who experienced snoring and occasional asphyxia during sleep. Upper endoscopy was performed, which indicated the presence of a pedunculated esophageal polyp that regurgitated into the vocal cords. The polyp was removed using a polypectomy snare and was confirmed to be a fibrovascular polyp based on pathologic examination findings. Three months after the excision of the polyp, the patient was found to be doing well without any further occurrence of asphyxia or sleep disturbances.

Ischemic biliary stricture developed after repeated transcatheter arterial chemoembolization diagnosed by percutaneous transhepatic cholangioscopy in a patient with hepatocellular carcinoma

Ischemic bile duct stricture is one of the rare complications that occur after repeated transcatheter arterial chemoembolization (TACE). In the previously reported cases, the diagnosis was usually made by radiological imaging, ERCP, and/or cholangiography. We report a case of ischemic bile duct stricture after repeated TACE in which the diagnosis was confirmed by percutaneous transhepatic cholangioscopy (PTCS). To our knowledge, this is the first case diagnosed by PTCS.

The Ballooning Time in Endoscopic Papillary Balloon Dilation for the Treatment of Bile Duct Stones

Background/Aims Endoscopic papillary balloon dilation (EPBD) is a safe and effective method for the treatment of choledocholithiasis, but previous studies have rarely reported the appropriate ballooning time (BT). We prospectively evaluated the safety and efficacy of EPBD according to BT in patients undergoing bile duct stone removal. Methods Seventy consecutive patients with bile duct stones were randomly assigned to receive EPBD with either conventional (n = 35, 60 seconds) or short (n = 35, 20 seconds) BT. Results EPBD alone achieved complete bile duct clearance in 67 patients (long BT, n = 33, 94.3%; short BT, n = 34, 97.1%; p = 0.808). We also found no significant difference in the rate of complete duct clearance, including procedures that used mechanical lithotripsy, between the long and short BT groups (97.1% vs. 100%; p = 0.811). Mild pancreatitis was noted in four (11.4%) patients in the long BT group and two (5.7%) patients in the short BT group, but this incidence was not significantly different. Conclusions The study showed that EPBD using both 20-sec and 60-sec BTs is safe and effective for the treatment of bile duct stones. Short and long BTs produced comparable outcomes.

Curved Planar Reformatted Images of MDCT for Differentiation of Biliary Stent Occlusion in Patients With Malignant Biliary Obstruction

OBJECTIVE We prospectively evaluated the usefulness of MDCT using a curved planar reformation technique for the noninvasive assessment of the causes of biliary stent occlusion in patients with malignant biliary obstruction. SUBJECTS AND METHODS Between December 2004 and January 2009, 173 patients with unresectable malignant biliary obstruction underwent biliary stent insertion. Among them, 26 patients with suspected biliary stent occlusion underwent 29 sessions of ERCP within 2 weeks after MDCT was performed. Curved planar reformation images were obtained along the pathway of the biliary stent. We interpreted tissue growth or stent clogging by comparing attenuation values inside the biliary stent between the unenhanced and contrast-enhanced phases of CT. The cause of biliary stent occlusion was confirmed by using ERCP. RESULTS The differences in attenuation value inside the biliary stent between the contrast-enhanced and unenhanced phases of CT in the tissue growth group was 27.7 +/- 21.7 HU (SD) and 4.2 +/- 10.6 HU in the stent-clogging group (p = 0.002). The sensitivity and specificity of MDCT for the diagnosis of tissue growth were 86.7% and 85.7%, respectively. The overall accuracy of curved planar reformation images of MDCT for diagnosing the causes of stent occlusion was 86.2%. CONCLUSION Curved planar reformation MDCT is a useful noninvasive technique that is relatively accurate for diagnosing the cause of biliary stent occlusion and is helpful for planning the therapeutic management of such patients.