Role of endoscopic ultrasound in the characterization of solid pseudopapillary neoplasm of the pancreas

BACKGROUND Solid pseudopapillary neoplasm(SPN)is an uncommon pathology of the pancreas with unpredictable malignant potential.Endoscopic ultrasound(EUS)assessment plays a vital role in lesion characterization and confirmation of the tissue diagnosis.However,there is a paucity of data regarding the imaging assessment of these lesions.AIM To determine the characteristic EUS features of SPN and define its role in preoperative assessment.METHODS This was an international,multicenter,retrospective,observational study of prospective cohorts from 7 large hepatopancreaticobiliary centers.All cases with postoperative histology of SPN were included in the study.Data collected included clinical,biochemical,histological and EUS characteristics.RESULTS One hundred and six patients with the diagnosis of SPN were included.The mean age was 26 years(range 9 to 70 years),with female predominance(89.6%).The most frequent clinical presentation was abdominal pain(80/106;75.5%).The mean diameter of the lesion was 53.7 mm(range 15 to 130 mm),with the slight predominant location in the head of the pancreas(44/106;41.5%).The majority of lesions presented with solid imaging features(59/106;55.7%)although 33.0%(35/106)had mixed solid/cystic characteristics and 11.3%(12/106)had cystic morphology.Calcification was observed in only 4(3.8%)cases.Main pancreatic duct dilation was uncommon,evident in only 2 cases(1.9%),whilst common bile duct dilation was observed in 5(11.3%)cases.One patient demonstrated a double duct sign at presentation.Elastography and Doppler evaluation demonstrated inconsistent appearances with no emergence of a predictable pattern.EUS guided biopsy was performed using three different types of needles:Fine needle aspiration(67/106;63.2%),fine needle biopsy(37/106;34.9%),and Sonar Trucut(2/106;1.9%).The diagnosis was conclusive in 103(97.2%)cases.Ninety-seven patients were treated surgically(91.5%)and the post-surgical SPN diagnosis was confirmed in all cases.During the 2-year follow-up period,no recurrence was observed.CONCLUSION SPN presented primarily as a solid lesion on endosonographic assessment.The lesion tended to be located in the head or body of the pancreas.There was no consistent characteristic pattern apparent on either elastography or Doppler assessment.Similarly SPN did not frequently cause stricture of the pancreatic duct or common bile duct.Importantly,we confirmed that EUS-guided biopsy was an efficient and safe diagnostic tool.The needle type used does not appear to have a significant impact on the diagnostic yield.Overall SPN remains a challenging diagnosis based on EUS imaging with no pathognomonic features.EUS guided biopsy remains the gold standard in establishing the diagnosis.

Endoscopic ultrasound guided radiofrequency ablation,for pancreatic cystic neoplasms and neuroendocrine tumors

AIM: To outline the feasibility, safety, adverse events and early results of endoscopic ultrasound(EUS)-radiofrequency ablation(RFA) in pancreatic neoplasms using a novel probe. METHODS: This is a multi-center, pilot safety feasibility study. The intervention described was radiofrequency ablation(RF) which was applied with an innovative monopolar RF probe(1.2 mm Habib EUS-RFA catheter) placed through a 19 or 22 gauge fine needle aspiration(FNA) needle once FNA was performed in patients with a tumor in the head of the pancreas. The HabibTM EUSRFA is a 1 Fr wire(0.33 mm, 0.013") with a working length of 190 cm, which can be inserted through the biopsy channel of an echoendoscope. RF power is applied to the electrode at the end of the wire to coagulate tissue in the liver and pancreas.RESULTS: Eight patients [median age of 65(range 27-82) years; 7 female and 1 male] were recruited in a prospective multicenter trial. Six had a pancreatic cysticneoplasm(four a mucinous cyst, one had intraductal papillary mucinous neoplasm and one a microcystic adenoma) and two had a neuroendocrine tumors(NET) in the head of pancreas. The mean size of the cystic neoplasm and NET were 36.5 mm(SD ± 17.9 mm) and 27.5 mm(SD ± 17.7 mm) respectively. The EUSRFA was successfully completed in all cases. Among the 6 patients with a cystic neoplasm, post procedure imaging in 3-6 mo showed complete resolution of the cysts in 2 cases, whilst in three more there was a 48.4% reduction [mean pre RF 38.8 mm(SD ± 21.7 mm) vs mean post RF 20 mm(SD ± 17.1 mm)] in size. In regards to the NET patients, there was a change in vascularity and central necrosis after EUS-RFA. No major complications were observed within 48 h of the procedure. Two patients had mild abdominal pain that resolved within 3 d. CONCLUSION: EUS-RFA of pancreatic neoplasms with a novel monopolar RF probe was well tolerated in all cases. Our preliminary data suggest that the procedure is straightforward and safe. The response ranged from complete resolution to a 50% reduction in size.

Per oral cholangiopancreatoscopy in pancreatico biliary diseases- Expert consensus statements

AIM: To provide consensus statements on the use of per-oral cholangiopancreatoscopy(POCPS).METHODS: A workgroup of experts in endoscopic retrograde cholangiopancreatography(ERCP), endosonography, and POCPS generated consensus statements summarizing the utility of POCPS in pancreaticobiliary disease. Recommendation grades used validated evidence ratings of publications from an extensive literature review.RESULTS: Six consensus statements were generated:(1) POCPS is now an important additional tool during ERCP;(2) in patients with indeterminate biliary strictures, POCS and POCS-guided targeted biopsy are useful for establishing a definitive diagnosis;(3) POCS and POCS-guided lithotripsy are recommended for treatment of difficult common bile duct stones when standard techniques fail;(4) in patients with main duct intraductal papillary mucinous neoplasms(IPMN) POPS may be used to assess extent of tumor to assist surgicalresection;(5) in difficult pancreatic ductal stones,POPS-guided lithotripsy may be useful in fragmentation and extraction of stones; and(6) additional indications for POCPS include selective guidewire placement,unexplained hemobilia, assessing intraductal biliary ablation therapy, and extracting migrated stents. CONCLUSION: POCPS is important in association with ERCP, particularly for diagnosis of indeterminate biliary strictures and for intra-ductal lithotripsy when other techniques failed, and may be useful for preoperative assessment of extent of main duct IPMN, for extraction of difficult pancreatic stones, and for unusua indications involving selective guidewire placement,assessing unexplained hemobilia or intraductal biliary ablation therapy, and extracting migrated stents.