MDCT evaluation of the growth kinetics of serous and benign mucinous cystic neoplasms of the pancreas

Mucinous cystic neoplasms of the pancreas: high-resolution cross-sectional imaging features with clinico-pathologic correlation

PURPOSE

To describe the high-resolution cross-sectional (MDCT/MRI) features of mucinous cystic neoplasms (MCN) of the pancreas with clinico-pathologic correlation; to identify imaging predictors of high-grade dysplasia/carcinoma; and to estimate MCN growth rate.

MATERIALS AND METHODS

Thirty-two women (mean age: 46; range, 25-79 years) with resected MCN who underwent preoperative MDCT (n = 20) or MRI (n = 12) examinations over a 14-year period were included. Two radiologists examined retrospectively in consensus the following MDCT/MRI features: MCN location, size/volume, presence of capsule and thickness of the capsule, and presence of mural nodules, enhancing septations, calcifications, chronic pancreatitis, and main pancreatic duct dilation. Imaging features were correlated with clinical symptoms, biochemistry results, and histopathologic features. A univariate model was analyzed for the prediction of high-grade dysplasia/carcinoma. Preoperative MCN growth rate was assessed using a subset of patients with more than one imaging study available (n = 6).

RESULTS

Twenty-five (78%) patients presented with symptoms and 8 (25%) patients had abnormal serum biochemical values. Mean MCN maximum dimensions were 48 × 45 × 45 mm with a mean volume of 169 mL. MCN were located in the tail (n = 18), body (n = 10), neck (n = 2), and (head = 2); 30 (93.5%) MCN were encapsulated, 3 (9%) had calcifications, 4 (12%) showed enhancing nodules, 9 (28%) had enhancing septations, and 5 (15%) had main pancreatic duct dilation. Associated chronic pancreatitis was observed in 4 (12%) patients. The only predictors for high-grade dysplasia/carcinoma were MCN size and volume. Using a cut-off size greater than 8.5 cm, the specificity and sensitivity for high-grade dysplasia/carcinoma were 97 and 60%, respectively (p = 0.003; OR 81, 95% CI 3.9-1655.8). Mean MCN growth rate was estimated at 4.2 mm/year with a doubling time of 8.23 years.

CONCLUSION

MCN size (> 8.5 cm) and volume are the only features on MDCT/MR imaging that correlate with high-grade dysplasia/carcinoma. The average growth rate for MCNs is slow at approximately 4 mm per year.

European evidence-based guidelines on pancreatic cystic neoplasms

Evidence-based guidelines on the management of pancreatic cystic neoplasms (PCN) are lacking. This guideline is a joint initiative of the European Study Group on Cystic Tumours of the Pancreas, United European Gastroenterology, European Pancreatic Club, European-African Hepato-Pancreato-Biliary Association, European Digestive Surgery, and the European Society of Gastrointestinal Endoscopy. It replaces the 2013 European consensus statement guidelines on PCN. European and non-European experts performed systematic reviews and used GRADE methodology to answer relevant clinical questions on nine topics (biomarkers, radiology, endoscopy, intraductal papillary mucinous neoplasm (IPMN), mucinous cystic neoplasm (MCN), serous cystic neoplasm, rare cysts, (neo)adjuvant treatment, and pathology). Recommendations include conservative management, relative and absolute indications for surgery. A conservative approach is recommended for asymptomatic MCN and IPMN measuring <40 mm without an enhancing nodule. Relative indications for surgery in IPMN include a main pancreatic duct (MPD) diameter between 5 and 9.9 mm or a cyst diameter ≥40 mm. Absolute indications for surgery in IPMN, due to the high-risk of malignant transformation, include jaundice, an enhancing mural nodule >5 mm, and MPD diameter >10 mm. Lifelong follow-up of IPMN is recommended in patients who are fit for surgery. The European evidence-based guidelines on PCN aim to improve the diagnosis and management of PCN.