Proposal for a New Pathologic Prognostic Index After Neoadjuvant Chemotherapy in Pancreatic Ductal Adenocarcinoma (PINC).

BACKGROUND: Limited information is available on the relevant prognostic variables after surgery for patients with pancreatic ductal adenocarcinoma (PDAC) subjected to neoadjuvant chemotherapy (NACT). NACT is known to induce a spectrum of histological changes in PDAC. Different grading regression systems are currently available; unfortunately, they lack precision and accuracy. We aimed to identify a new quantitative prognostic index based on tumor morphology. PATIENTS AND METHODS: The study population was composed of 69 patients with resectable or borderline resectable PDAC treated with preoperative NACT (neoadjuvant group) and 36 patients submitted to upfront surgery (upfront-surgery group). A comprehensive histological assessment on hematoxylin and eosin (H&E) stained sections evaluated 20 morphological parameters. The association between patient survival and morphological variables was evaluated to generate a prognostic index. RESULTS: The distribution of morphological parameters evaluated was significantly different between upfront-surgery and neoadjuvant groups, demonstrating the effect of NACT on tumor morphology. On multivariate analysis for patients that received NACT, the predictors of shorter overall survival (OS) and disease-free survival (DFS) were perineural invasion and lymph node ratio. Conversely, high stroma to neoplasia ratio predicted longer OS and DFS. These variables were combined to generate a semiquantitative prognostic index based on both OS and DFS, which significantly distinguished patients with poor outcomes from those with a good outcome. Bootstrap analysis confirmed the reproducibility of the model. CONCLUSIONS: The pathologic prognostic index proposed is mostly quantitative in nature, easy to use, and may represent a reliable tumor regression grading system to predict patient outcomes after NACT followed by surgery for PDAC.

Urgent manifestations of immunoglobulin G4-related disease.

Objective: Immunoglobulin G4-related disease (IgG4-RD) is considered a chronic condition with insidious presentation, but clinical experience suggests that disease onset prompts admission to the emergency department (ED) in a sizeable proportion of patients. We assessed the prevalence of acute manifestations associated with IgG4-RD onset requiring referral to the ED. Method: We revised our database and identified patients admitted to the ED because of symptoms latterly attributed to IgG4-RD onset (Group 1) and those who were referred to our outpatient clinic without previous urgent manifestations (Group 2). Acute manifestations were clustered based on the anatomical region affected by IgG4-RD. Epidemiological, clinical, and serological features of Groups 1 and 2 were compared. Results: The study included 141 patients with IgG4-RD. Of these, 76 (54%) presented to the ED at disease onset. The most common clinical manifestations requiring admission to the ED were jaundice (53%), abdominal pain (41%), and fever (10%). Gastrointestinal involvement was the most frequent cause of referral to the ED (71% of cases), followed by involvement of the retroperitoneum (14.5%) and the nervous system (6.6%). Pancreatobiliary involvement was significantly more frequent in Group 1 than in Group 2. Head and neck, and salivary and lacrimal gland involvement was more frequent in Group 2 than in Group 1. The diagnostic delay was significantly shorter in Group 1 than in Group 2. Conclusion: Clinical manifestations associated with IgG4-RD onset require referral to the ED in most cases. This finding contrasts with the general view of IgG4-RD as a condition with non-acute presentation.

Meta-analysis of mortality in patients with high-risk intraductal papillary mucinous neoplasms under observation.

BACKGROUND: Although consensus guidelines suggest that patients with high-risk intraductal papillary mucinous neoplasms (IPMNs) should have surgery, a non-operative strategy is often selected in patients who are poor surgical candidates. The aim was to determine the risk of disease-related death from IPMN in patients with worrisome features or high-risk stigmata who were kept under observation. METHODS: A PubMed literature search was undertaken of articles published from August 1992 to June 2016 (updated October 2017). The methodology was developed from PRISMA and MOOSE checklists. Incidence proportions and rates of overall and IPMN-related deaths were calculated, with subgroup analyses for main-duct/mixed-type and branch-duct IPMNs. Quality of the studies, publication bias and heterogeneity were explored. RESULTS: Six studies reported data on overall mortality and eight described disease-specific mortality for 556 patients during follow-up ranging from 24·9 to 60·0 months. Pooled rates of overall and IPMN-related mortality were 30·9 (95 per cent c.i. 19·6 to 45·1) and 11·6 (6·0 to 21·2) per cent respectively. The pooled incidence rate for overall mortality was substantially higher than that for IPMN-related mortality: 78 (95 per cent c.i. 44 to 111) and 23 (9 to 37) per 1000 patient-years respectively. The pooled incidence rate for disease-specific mortality was considerably lower for branch-duct than for main-duct or mixed-type IPMNs: 5 (0 to 10) and 32 (12 to 52) per 1000 patient-years respectively. CONCLUSION: In patients unfit for surgery, IPMN-related mortality among patients with worrisome features and high-risk stigmata is low, and the risk of death from other causes much higher.

Selecting patients for resection after primary chemotherapy for non-metastatic pancreatic adenocarcinoma.

BACKGROUND: Patients with borderline (BL) or locally advanced (LA) pancreatic adenocarcinoma are usually treated with primary chemotherapy (CT), followed by resection when feasible. Scanty data are available about the criteria to candidate patients to resection after CT. PATIENTS AND METHODS: Between 2002 and 2016 overall 223 patients diagnosed with BL or LA pancreatic adenocarcinoma were primarily treated with Gemcitabine combination (4-drugs or nab-paclitaxel-gemcitabine) for 3-6 months followed by surgery and/or chemoradiation. Resection was carried out when radical resection could be predicted by imaging studies and intraoperative findings. The prognostic value of both pre-treatment factors and treatment response was retrospectively evaluated, searching for criteria that could improve the selection of patients for surgery. RESULTS: Median survival (MS) for the whole population was 18.3 months. Surgical resection was carried out in 61 patients; MS in resected patients was significantly longer (30.0 months) as compared with 162 non-resected patients (16.5 months) (P < 0.00001). According to response criteria, 48% had a radiological partial response, 47% a stable disease and 5% a disease progression); CA19.9 response (reduction >50%) was obtained in 77.8% of patients. Among resected patients, neither pre-treatment factors, including BL/LA distinction, nor radiological response, were able to prognosticate survival differences. Survival of resected patients having no CA19.9 response was significantly lower as compared with responders (MS 15.0 versus 31.5 months, P = 0.04), and was similar to non-responders patients that did not undergo resection (MS 10.9 months, P= 0.25). Multivariate analysis carried out on the overall population, showed that Karnofsky performance status, T3-T4 status, resection and CA19.9 response were independent prognostic factors, while radiological response, BL/LA distinction and baseline CA19.9 had not significant influence on survival. CONCLUSIONS: CA19.9 response may allow a better selection of patients who will benefit from resection after primary CT for BL or LA pancreatic adenocarcinoma.

Prevalence and risk factors of extrapancreatic malignancies in a large cohort of patients with intraductal papillary mucinous neoplasm (IPMN) of the pancreas.

BACKGROUND: The objectives of this study are to estimate prevalence and incidence of extrapancreatic malignancies (EPMs) among intraductal papillary mucinous neoplasms (IPMNs) of the pancreas, and to identify risk factors for their occurrence. PATIENTS AND METHODS: We conducted multicentric cohort study in Italy from January 2010 to January 2011 including 390 IPMN cases. EPMs were grouped as previous, synchronous (both prevalent) and metachronous (incident). We calculated the observed/expected (O/E) ratio of prevalent EPMs, and compared the distribution of demographic, medical history and lifestyle habits. RESULTS: Ninety-seven EPMs were diagnosed in 92 patients (23.6%), among them 78 (80.4%) were previous, 14 (14.4%) were synchronous and 5 (5.2%) were metachronous. O/E ratios for prevalent EPMs were significantly increased for colorectal carcinoma (2.26; CI 95% 1.17-3.96), renal cell carcinoma (6.00; CI 95% 2.74-11.39) and thyroid carcinoma (5.56; CI 95% 1.80-12.96). Increased age, heavy cigarette smoking, alcohol consumption and first-degree family history of gastric cancer are significant risk factors for EPMs, while first-degree family history of colorectal carcinoma was borderline. CONCLUSION: We report an increased prevalence of EPMs in Italian patients with IPMN, especially for colorectal carcinoma, renal cell and thyroid cancers. A systematic surveillance of IPMN cases for such cancer types would be advised.

Endoscopic ultrasound-guided application of a new internally gas-cooled radiofrequency ablation probe in the liver and spleen of an animal model: a preliminary study.

BACKGROUND AND STUDY AIMS: In a previous study, a new flexible bipolar hybrid cryotherm probe was applied with success to the pancreas of a living pig. Here we evaluated feasibility, efficacy, and safety of its application to the porcine liver and spleen. MATERIAL AND METHODS: Ten applications to the liver and nine to the spleen were performed in 19 pigs. Power input (16-18 W) and simultaneous cooling with CO(2) (standardized pressure: 675 psi) as the cryogenic agent were investigated. Application time varied from 120 seconds to 900 seconds. The ablation area was measured by endoscopic ultrasound (EUS) after ablation (T0), and before euthanasia (T1). Gross pathology (T2) and histology after necropsy represented the gold standard. The interval from treatment to euthanasia was 1 or 2 weeks. RESULTS: For both organs the correlation between EUS and gross pathology was good (correlation coefficient R(liver) = 0.71; R(spleen) = 0.73). EUS tended to overestimate the area of the ablated zone. EUS observed a time-dependent ablation area: we demonstrated a positive trend of lesion size (T1) over time in liver tissue (R = 0.51 (P = 0.1)). In the spleen we found a clear correlation of lesion area T2 and application time (R = 0.75, P = 0.01). There were no complications. CONCLUSIONS: Selective EUS-guided transgastric cryotherm ablation of the liver and spleen in a pig model is feasible and safe. The new bipolar probe creates a time-dependent ablation area without any complications, and opens a field of new potential indications of RF-ablative therapies.

Endoscopic ultrasound-guided application of a new hybrid cryotherm probe in porcine pancreas: a preliminary study.

BACKGROUND AND STUDY AIMS: Open, laparoscopic, or percutaneous radiofrequency (RF) ablation of the pancreas is still dangerous, whereas endoscopic ultrasound (EUS)-guided ablation might reduce risk because it is less invasive and provides real-time monitoring. We aimed to demonstrate the feasibility of transluminal RF ablation and to evaluate the efficacy and safety of a new flexible bipolar ablation probe combining RF and cryotechnology. METHODS: 14 ablations were performed in 14 pigs. Energy input (16 W) and simultaneous cryogenic cooling with carbon dioxide (650 psi) were standardized. Application time range was 120 - 900 seconds. Ablation area was measured by EUS immediately after ablation (area T0), and before euthanasia (area T1). Macroscopic findings (area T2) and histological findings after necropsy served as gold standard. The interval from application to euthanasia was either 1 or 2 weeks. RESULTS: The correlation between EUS findings (area T1) and macroscopic appearance (area T2) was good ( R = 0.89). The correlation between the T2 ablation area and the application time showed a fitted ratio of 2.3 ( P < 0.0001) with a 1-week interval and 0.2 ( P = 0.01) with a 2-week interval. No pig died because of the procedure. Two pigs showed histochemical pancreatitis, which was clinically overt in one. Necropsy additionally revealed one burn to the gastric wall and four gut adhesions. CONCLUSIONS: Selective transluminal RF ablation of the pancreas under EUS control in a living pig model is feasible. The new flexible bipolar probe creates an ablation area with extent related to the duration of application, and with fewer complications than conventional RF ablation techniques.

Midazolam and pethidine versus propofol and fentanyl patient controlled sedation/analgesia for upper gastrointestinal tract ultrasound endoscopy: a prospective randomized controlled trial.

BACKGROUND AND OBJECTIVES: The aim of this prospective, randomized study was to compare the standard regimen of midazolam and pethidine administered by the gastroenterologist versus patient controlled sedation with a propofol-fentanyl mixture during upper gastrointestinal tract endoscopic ultrasonography. Our primary end-points were patient satisfaction and patient cooperation assessed by endoscopist. METHODS: Fifty-four consecutive patients, undergoing endoscopic ultrasonography, received sedation with midazolam and pethidine (Group M: n=27) or propofol and fentanyl (Group P: n=27). Group M: pethidine 0.7mg/kg midazolam 0.04mg/kg before examination; boluses of same drugs if the sedation was insufficient plus a sham patient controlled sedation analgesia; Group P: propofol 17mg plus fentanyl 15microg before examination and a patient controlled sedation analgesia pump containing 170mg propofol plus 150microg fentanyl injecting 0.5ml every time the patient pressed the button (no "lock out"). Boluses of 1ml of the same mixture if the sedation was insufficient. RESULTS: Group M: mean dosage of pethidine and midazolam 88.6 and 5mg, respectively. Group P: mean dosage of propofol and fentanyl 119.7mg and 106microg, respectively. Both groups were similar for duration and difficulty of the procedure, the grade of sedation (Observer's Assessment of Alertness/Sedation Score) and judgement by endoscopist and patient about cooperation and satisfaction. The only difference between groups was about the extra boluses administered during the procedure. CONCLUSION: This study demonstrated that a patient controlled sedation analgesia with propofol and fentanyl is an effective and safe technique for upper gastrointestinal tract endoscopic ultrasonography procedures and results in a high level of satisfaction both for patients and operator.

Target-controlled infusion during monitored anesthesia care in patients undergoing EUS: propofol alone versus midazolam plus propofol. A prospective double-blind randomised controlled trial.

BACKGROUND: It has been speculated that midazolam may be effective in reducing the required dose of propofol during sedation. AIM: To evaluate the sparing effect of midazolam during target-controlled propofol infusion. METHODS: Two hundred-seventy patients undergoing upper endoscopic ultrasound were randomised to receive sedation with propofol plus placebo (group A) or plus midazolam (group B). Outcome parameters were the procedure duration, the discharge time and the satisfaction of patients, operator and nurse about the quality of sedation. RESULTS: The mean propofol dose administered was 364+/-207 mg in group A and 394+/-204 mg in group B. Mean procedure duration (group A: 32+/-17 min, group B: 35+/-22 min) and discharge time (group A: 39+/-30 min, group B: 38+/-24 min) were similar in both groups. No severe complications were observed. The quality of sedation was judged satisfactory for all patients by both the endoscopist and the nurse assistant without any difference between the two groups. No patient remembered the procedure or reported it as unpleasant. CONCLUSIONS: Target-controlled propofol infusion provides safe and effective sedation; premedication with low dose of midazolam does not reduce the total amount of propofol administered. Further studies are needed to compare propofol alone with propofol co-administered with opioid.

Optical coherence tomography compared with histology of the main pancreatic duct structure in normal and pathological conditions: an 'ex vivo study'.

BACKGROUND AND STUDY AIMS: Optical coherence tomography permits high-resolution imaging of tissue microstructures by a probe inserted into the main pancreatic duct through a standard ERCP catheter. The aim of this study was to compare optical coherence tomography images of the main pancreatic duct with histology and identify the optical coherence tomography pattern of the normal and pathological structure of the main pancreatic duct. PATIENTS AND METHODS: Multiple sections of neoplastic and non-neoplastic segments of 10 consecutive surgical pancreatic specimens obtained from patients with pancreatic head adenocarcinoma were investigated by optical coherence tomography scanning within 1h of resection. One hundred optical coherence tomography findings were then compared with the corresponding histopathological diagnoses. RESULTS: Main pancreatic duct wall architecture appeared at optical coherence tomography investigation as a three-layer structure with a different back-scattered signal from each layer. Optical coherence tomography imaging was concordant with histology in 81.8% and 18.75% of sections with normal tissue and chronic inflammatory changes. The K statistic between the two procedures was equal to 0.059 for non-neoplastic main pancreatic duct wall appearance. In all neoplastic sections optical coherence tomography showed a subverted layer architecture with heterogeneous back-scattering of the signal and was concordant with histology. CONCLUSIONS: Optical coherence tomography provided images of main pancreatic duct wall structure that were concordant with histology in 100% of cases in presence of neoplastic ductal changes and did not have false-positive or negative results. Optical coherence tomography images were also concordant with histology in about 80% of cases with normal main pancreatic duct structure; however, the differential diagnosis between normal tissue and chronic pancreatitis or dysplastic changes appeared very difficult.

Main pancreatic duct, common bile duct and sphincter of Oddi structure visualized by optical coherence tomography: An ex vivo study compared with histology.

BACKGROUND: Optical coherence tomography has been proposed to obtain high-resolution imaging of tissue structure of GI tract. Up till now, the optical coherence tomography appearance of the common bile duct, main pancreatic duct and sphincter of Oddi wall structure has not yet been defined. AIMS: To compare, in a prospective study, optical coherence tomography images of pancreato-biliary ductal system with histology and identify the optical coherence tomography pattern of the normal wall structure of the ducts. METHODS: Multiple sections of non-neoplastic segments of five consecutive ex vivo human pancreatic specimens were investigated by optical coherence tomography scanning within 1h of resection. Sixty optical coherence tomography images were compared with the corresponding histological findings. RESULTS: Optical coherence tomography appearance of normal common bile duct, main pancreatic duct and sphincter of Oddi is characterized by a differentiated three-layer architecture with a regular surface and a homogeneous back-scattered signal, corresponding to the single layer of epithelial cells, the connective-muscular layer and the muscular or acinar structure, respectively. Optical coherence tomography and histology findings were concordant in all cases. CONCLUSIONS: Optical coherence tomography was able to provide in real-time images of wall structure of the normal common bile duct, main pancreatic duct and sphincter of Oddi that are similar to those obtained by histology. These results suggest that optical coherence tomography could enable high-resolution images to be obtained from the pancreato-biliary system during an ERCP procedure.

Multicentre retrospective study on endoscopic ultrasound complications.

BACKGROUND: Endoscopic ultrasonography, both conventional and interventional, has been used increasingly during the past 20 years and is deemed a safe technique. Its complication rate, however, has been studied to only a limited extent. This multicentre investigation sought to establish the complication rate for a large number of endoscopic ultrasonography procedures. METHODS: By means of a questionnaire, we collected data from six centres on the number of endoscopic ultrasonography examinations performed and divided them into conventional and interventional examinations of the upper and lower gastrointestinal tract. Information was obtained on technical modalities such as instruments and sedation and, for interventional endoscopic ultrasonography, indications, pre-procedural exams and technical details (needle calibre, number of passes) had to be specified. Complications were classified as mild, moderate, severe or fatal and their onset as immediate, early or late. Variables that entered into the analysis of complication rate included type of endoscopic ultrasonography instrument used, type and site of lesion biopsied, number of needle passes and operator experience. RESULTS: Eleven thousand five hundred thirty nine endoscopic ultrasonographic procedures were reported, of which 10,731 were conventional and 808 interventional. No deaths occurred; there were 14 (0.12%) complications, 5 (0.046%) of them following conventional endoscopic ultrasonography and 9 (1.11%) after interventional endoscopic ultrasonography. Seven complications were mild, four moderate and three severe. CONCLUSIONS: Both conventional and interventional endoscopic ultrasonography were confirmed to be acceptably safe techniques.

Systematic review and meta-analysis of metal versus plastic stents for preoperative biliary drainage in resectable periampullary or pancreatic head tumors.

BACKGROUND: Preoperative biliary drainage (PBD) with stenting increases complications compared with surgery without PBD. Metallic stents are considered superior to plastic stents when considering stent-related complications. Aim of the present systematic review and meta-analysis is to compare the rate of endoscopic re-intervention before surgery and postoperative outcomes of metal versus plastic stents in patients with resectable periampullary or pancreatic head neoplasms. METHODS: We conducted a bibliographic research using the National Library of Medicine's PubMed database, including both randomized controlled trials (RCTs) and non-RCTs. Quantitative synthesis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Statistical heterogeneity was assessed using the I(2) tests. RESULTS: One RCT and four non-RCTs were selected, including 704 patients. Of these, 202 patients (29.5%) were treated with metal stents and 502 (70.5%) with plastic stents. The majority of patients (86.4%) had pancreatic cancer. The rate of endoscopic re-intervention after preoperative biliary drainage was significantly lower in the metal stent (3.4%) than in the plastic stent (14.8%) group (p < 0.0001). The rate of postoperative pancreatic fistula was significantly lower in the meta stent group as well (5.1% versus 11.8%, p = 0.04). The rate of post-operative surgical complications and of - post-operative mortality did not differ between the two groups. CONCLUSIONS: Although the present systematic review and meta-analysis demonstrates that metal stent are more effective than plastic stents for PBD in patients with resectable periampullary tumors, randomized controlled trials are needed in order to confirm these data with a higher level of evidence.

Endoscopic ultrasound in the evaluation of pancreaticobiliary disorders.

The close proximity of the endoscopic ultrasound probe to the pancreas coupled with the ability to perform fine needle aspiration has made endoscopic ultrasound an extremely important technique for the evaluation of both benign and malignant pancreaticobiliary disorders. In parallel to the widespread importance of diagnostic endoscopic ultrasound, the therapeutic and interventional applications of this procedure are expanding and may become a major breakthrough in the management of pancreaticobiliary diseases. This article focuses on the utility and recent advances of endoscopic ultrasound in the diagnostic evaluation pancreaticobiliary disorders and analyses the data of well established interventional procedures such as celiac plexus neurolysis and pseudocyst drainage. Moreover, the more innovative procedures, such endoscopic ultrasound-guided biliary and pancreatic ducts access and drainage and the experimental use of direct endoscopic ultrasound-guided therapy of both solid and cystic pancreatic lesions will also be reviewed.

Diagnostic yield of ERCP and secretin-enhanced MRCP and EUS in patients with acute recurrent pancreatitis of unknown aetiology.

BACKGROUND: Magnetic resonance cholangio-pancreatography (MRCP), endoscopic ultrasonography (EUS), and endoscopic cholangio-pancreatography (ERCP) are the most frequently employed second-step procedures to detect biliary and pancreatic abnormalities in patients with acute recurrent pancreatitis (ARP) of unknown aetiology. MRCP and EUS both give a better view of the bilio-pancreatic ductal system after secretin stimulation (MRCP-S, EUS-S). EUS also serves to identify changes in the pancreatic parenchyma consistent with chronic pancreatitis, at an early stage. However, no studies have compared MRCP-S, EUS-S, and ERCP in the diagnosis of recurrent pancreatitis. AIM: To prospectively compare the diagnostic yield of MRCP-S, EUS-S, and ERCP in the evaluation of patients with acute recurrent pancreatitis with non-dilated ducts, of unknown aetiology. METHODS: Forty-four consecutive patients with ARP were prospectively scheduled to undergo MRCP-S, EUS-S and ERCP, in accordance with a standard protocol approved by the institutional review board. Diagnoses such as biliary microlithiasis, congenital variants of the pancreatic ducts, chronic pancreatitis and sphincter of Oddi dysfunction were compared between the three procedures. The diagnosis of chronic pancreatitis was established according to ductal morphology by MRCP-S and ERCP, ductal and parenchymal morphology by EUS-S. RESULTS: The three procedures combined achieved a diagnosis that could have explained the recurrence of pancreatitis in 28/44 patients (63.6%). EUS-S recognized ductal and/or parenchymal abnormalities with the highest frequency (35/44 patients, 79.5%). Both MRCP-S and EUS-S were superior to ERCP for detecting pancreatic ductal abnormalities. EUS-S showed up pancreatic parenchymal changes in more than half the cases. Both EUS and MRCP secretin kinetics were concordant in identifying two cases with sphincter of Oddi dysfunction. CONCLUSIONS: The diagnostic yield of EUS-S in recurrent pancreatitis with non-dilated ducts and unknown aetiology was 13.6% and 16.7% higher than MRCP-S and ERCP respectively (although not significant), which both gave substantially similar diagnostic yields. In no case did ERCP alone find a diagnosis missed by the other two procedures. MRCP-S and EUS-S should both be used in the diagnostic work-up of idiopathic recurrent pancreatitis as complementary, first-line, techniques, instead of ERCP.

Investigation of Oddi sphincter structure by optical coherence tomography in patients with biliary-type 1 dysfunction: a pilot in vivo study.

BACKGROUND: Type 1 sphincter of Oddi dysfunction is a clinical entity characterised by biliary-type pain, elevated liver biochemical tests, and common bile duct dilation. Sphincter fibrosis is a common finding in this type of dysfunction and may require in some cases a differential diagnosis with a malignant intra-papillary disease. Optical coherence tomography permits high-resolution, real-time imaging of the sphincter of Oddi microstructure by a probe inserted into the common bile duct through an ERCP catheter. No data exist on the evaluation of sphincter of Oddi fibrosis by optical coherence tomography during ERCP in vivo. OBJECTIVE: To assess the feasibility of optical coherence tomography investigation of the sphincter of Oddi structure and assess its potential for diagnosing type 1 sphincter of Oddi dysfunction. PATIENTS: Ten consecutive patients, five with biliary-type 1 sphincter of Oddi dysfunction and five with pancreatic head/mid-body adenocarcinoma not involving the papillary region, who underwent both endoscopic ultrasound and therapeutic ERCP, were investigated by optical coherence tomography immediately before biliary sphincterotomy or stenting. RESULTS: In all sphincter of Oddi dysfunction patients optical coherence tomography recognised a hyper-reflective intermediate, fibro-muscular layer, significantly thicker than in patients with non-pathological sphincter of Oddi (p<0.0001). CONCLUSIONS: Optical coherence tomography imaging recognised an increased thickness and reflectance of the fibro-muscular layer of the sphincter of Oddi, very likely determined by fibrosis, and was not time-consuming; it can be safely used during ERCP to confirm the diagnosis in difficult cases. Its use in clinical practice has one important limitation since it requires magnification in the post-procedure computer analysis to obtain images useful for diagnosis.