Pancreatic Cysts: Controversies, Advances, Diagnoses, and Therapies

Evaluating the accuracy of three international guidelines in identifying the risk of malignancy in pancreatic cysts: a retrospective analysis of a surgical treated population

BACKGROUND AND STUDY AIMS

The international consensus Fukuoka guideline (Fukuoka ICG), The European evidence-based guideline on pancreatic cystic neoplasms (European EBG) and the American Gastroenterological Association institute guideline on the diagnosis and management of asymptomatic neoplastic pancreatic cysts (AGA IG) are 3 frequently cited guidelines for the risk stratification of neoplastic pancreatic cysts. The aim of this study was to assess the accuracy of detecting malignant cysts by strictly applying these guidelines retrospectively to a cohort of surgically resected pancreatic cysts.

PATIENTS AND METHODS

72 resected cysts were included in the analysis. Invasive carcinoma, high grade dysplasia and neuro-endocrine tumour were considered as "malignant cysts" for the purpose of the study.

RESULTS

32% of the resected cysts were malignant. The analysis showed that the Fukuoka ICG, European EBG and AGA IG had a sensitivity of 66,8%, 95,5%, 80%; a specificity of 26,8%, 11,3%, 43,8%; a positive predictive value of 31,8%, 35%, 47,1% and a negative predicted value of 61,1%, 83,3%, 77,8% respectively. The missed malignancy rate was respectively 11,3%, 1,5%, 7,7% and surgical overtreatment was respectively 48,4%, 59,1%, 34,6%.

CONCLUSION

In this retrospective analysis, the European EBG had the lowest rate of missed malignancy at the expense of a high number of "unnecessary" resections. The Fukuoka ICG had the highest number of missed malignancy. The AGA IG showed the lowest rate of unnecessary surgery at the cost of a high number of missed malignancy. There is need to develop better biomarkers to predict the risk of malignancy.

Automated Detection of Pancreatic Cystic Lesions on CT Using Deep Learning

Pancreatic cystic lesions (PCL) are a frequent and underreported incidental finding on CT scans and can transform into neoplasms with devastating consequences. We developed and evaluated an algorithm based on a two-step nnU-Net architecture for automated detection of PCL on CTs. A total of 543 cysts on 221 abdominal CTs were manually segmented in 3D by a radiology resident in consensus with a board-certified radiologist specialized in abdominal radiology. This information was used to train a two-step nnU-Net for detection with the performance assessed depending on lesions' volume and location in comparison to three human readers of varying experience. Mean sensitivity was 78.8 ± 0.1%. The sensitivity was highest for large lesions with 87.8% for cysts ≥220 mm³ and for lesions in the distal pancreas with up to 96.2%. The number of false-positive detections for cysts ≥220 mm³ was 0.1 per case. The algorithm's performance was comparable to human readers. To conclude, automated detection of PCL on CTs is feasible. The proposed model could serve radiologists as a second reading tool. All imaging data and code used in this study are freely available online.

PET-MR Imaging and MR Texture Analysis in the Diagnosis of Pancreatic Cysts: A Prospective Preliminary Study

RATIONALE AND OBJECTIVES

Our aim was to evaluate the capability of textural and metabolic parameters measured at pretreatment ¹⁸F-fluorodeoxyglucose Positron emission tomography (PET)-MR in differentiating malignant from benign pancreatic cystic lesions.

MATERIALS AND METHOD

Forty consecutive patients were prospectively enrolled in this study. They underwent simultaneous PET-MR for the diagnosis of pancreatic cysts. Thirty texture parameters were extracted from manually contoured axial T2-weighted imaging with fat suppression (T2FS) and apparent diffusion coefficient images, respectively. Maximal and mean standardized uptake values (SUV_max and SUV_mean, respectively) of pancreatic cysts were measured at PET-MR imaging. The Mann-Whitney test was used to compare both textural and metabolic parameters between benign and malignant group.

RESULTS

FDG uptake was significantly higher in patients with malignant pancreatic cysts (SUV_maxp = 0.002, SUV_meanp < 0.001). Malignant cysts showed significantly lower standard deviation for spatial scaling factor at 3-6mm on T2FS images and lower skewness for spatial scaling factor at 2-4mm on apparent diffusion coefficient images (p < 0.01). SUV_mean had the highest Area under the curve of 0.892 on receiver-operating characteristic analysis with a sensitivity, specificity, and accuracy of 88.9%, 87.1%, and 87.6%, respectively. When metabolic and textural features were combined into a single diagnostic model, the AUC increased to 0.961, with a sensitivity, specificity, and accuracy of 88.9%, 96.8%, and 95.0%, respectively.

CONCLUSION

Our study implied that PET-MR showed no obvious advantages over traditional PET-related imaging in differentiating malignant from benign pancreatic cystic lesions. Diagnostic model based on the combination of metabolic and textural parameters showed satisfactory performance.

Pancreatic intraductal papillary mucinous neoplasm masquerading as ampullary adenoma: a diagnostic puzzle

Intraductal papillary mucinous neoplasm (IPMN) is the most common pancreatic cystic lesion, remaining mostly asymptomatic. An atypical presentation of such a lesion, initially thought to be an ampullary adenoma, is presented herein. A 78-year-old white male with painless jaundice was treated in a tertiary hospital. Imaging and endoscopic investigations pointed towards an ampullary adenoma obstructing and causing dilatation of both bile and pancreatic ducts. Endoscopic papillectomy was carried out and histology revealed tubulovillous adenoma. Follow-up duodenoscopy 3 months later showed a recurrent lesion with mucous leaking from the pancreatic duct. Cytology revealed mucin-rich atypical cells, consistent with main-duct IPMN. Pancreatoduodenectomy was performed, finally revealing main-duct IPMN protruding through Vater’s ampulla. Cystic pancreatic lesions are increasingly found and IPMN is the most common of these. On the other hand, the management of ampullary adenomas has been revolutionized by endoscopic treatment and the advent of endoscopic papillectomy, with expanding indications. Meticulous clinical and imaging work up of these patients is essential to avoid suboptimal treatment. IPMN should be included in the differential diagnosis of ampullary adenomas, especially in the presence of a grossly dilated pancreatic duct.

Cystic tumors of the pancreas. An update of the surgical experience in a single institution

BACKGROUND

the aim of the present study was to analyze the clinicopathological features of patients undergoing pancreatic surgical resections due to cystic neoplasms of the pancreas.

MATERIAL AND METHODS

demographic data, form of presentation, radiologic images and location of the tumors within the pancreas were analyzed. Data was also collected on the type of surgery (open/laparoscopic), postoperative complications and their severity and oncologic outcomes.

RESULTS

eighty-two pancreatic resections were performed. The mean age of patients was 57 years and 49 (59%) were female. Forty-one tumors (50%) were incidental and the most frequent symptoms in the group of symptomatic patients were abdominal pain (63.4%) and weight loss (36.5%). Thirty-two tumors (39%) were located in the tail of the pancreas, 25 (30.5%) in the head and 20 (24.4%) in the body. Thirty-nine (47.5%) distal pancreatectomies, 16 central, ten duodenal pancreatectomies and one enucleation were performed; 40 (48.5%) were carried out laparoscopically. Mean hospital stay was ten days and eight patients (7%) experienced severe complications, one was a pancreatic fistula. Sixty-six tumors (80.5%) were recorded as non-invasive and 16 (19.5%) as invasive: seven intraductal mucinous papillary tumors, one cystic mucinous tumor, four solid pseudopapillary tumors and four cystic neuroendocrine tumors. There was a median follow-up of 64 months; disease-free survival at five and ten years was 97.4% in the patients with non-invasive tumors and 84.6% and 70.5% in the invasive tumors group (p < 0.01).

CONCLUSIONS

fifty percent of cystic neoplasms of the pancreas are incidental. Two phenotypes exist, invasive and non-invasive.

Role of Radiological Imaging in the Diagnosis and Characterization of Pancreatic Cystic Lesions: A Systematic Review

The evidence on the ability of radiological tests to predict a specific diagnosis and also their aptitude in identifying pathological markers indicative of malignancy in cystic lesions of the pancreas remains inconclusive. We conducted a systematic review on MEDLINE for the use of computed tomography (CT), magnetic resonance imaging, and positron emission tomography/CT (PET/CT) in the diagnosis and characterization of these cysts. The accuracy of CT scan for reaching a specific diagnosis was 39% to 61.4%, whereas its accuracy for differentiating benign from malignant lesions was 61.9% to 80%. Magnetic resonance imaging showed a better accuracy in identifying a specific diagnosis of 50% to 86%, whereas its accuracy in differentiating benign from malignant lesions was 55.6% to 87%. The use of magnetic resonance imaging was superior to CT scan in identifying septations, mural nodules, and ductal communication. The sensitivity of PET/CT in diagnosing malignancy was 85.7% to 100% with a reported accuracy of 88% to 95%. The evidence gathered from this review suggests that the adequacy of CT imaging in full characterization of pancreatic cysts is suboptimal, and therefore a low threshold for supplementary imaging is advised. The use of PET/CT should be considered in high-risk patients with equivocal findings.

Cystic pancreatic neuroendocrine tumors (cPNETs): a systematic review and meta-analysis of case series

Cystic pancreatic neuroendocrine tumors represent 13% of all neuroendocrine tumors. The aim of this study is to analyze the phenotype and biologic behavior of resected cystic neuroendocrine tumors. A systematic review and meta-analysis were conducted until September 2016 using a search in Medline, Scopus, and EMBASE with the terms "cystic pancreatic endocrine neoplasm", "cystic islets tumors" and "cystic islets neoplasms". From the 795 citations recovered 80 studies reporting on 431 patients were selected. 87.1% (n = 387) were sporadic tumors and 10.3% (n = 40) corresponded to multiple endocrine neoplasia endocrine type 1. Were diagnosed incidentally 44.6% (n = 135). Cytology was found to have a sensitivity of 78.5%. Were non-functional tumors 85% (n = 338), and among the functional tumors, insulinoma was the most frequent. According to the European Neuroendocrine Tumor Society staging, 87.8% were limited to the pancreas (I-IIb), and 12.2% were advanced (III-IV). Disease-free survival at 5 years in stages (I-IIIa) and (IIIb-IV) was 91.5% and 54.2%, respectively; and was significantly lower (p = 0.0001) in functional tumors. In patients with multiple endocrine neoplasia there was a higher incidence of functional (62.5%) and multifocal (28.1%) tumors. Disease-free survival at 5 and 10 years was 60%. Cystic pancreatic neuroendocrine tumors exhibit phenotypical characteristics which are different to those of solid neuroendocrine tumors.