Intraductal Papillary Mucinous Neoplasm of the Pancreas: Need for a Tailored Approach to a Rare Entity

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is a relatively new entity that has gained increased attention because of its unique features – presence of different subtypes with different malignant potential, biological behavior, and prognosis, higher rates of recurrences and concomitant or metachronous pancreatic duct cancer. It is rare with an incidence of 4 to 5 cases per 100 000. The relative lack of experience significantly hampers decision making for surgery (pancreatic head resection, distal pancreatectomy or enucleation) or follow-up. Herein we present two cases managed by diametrically different tactic according to the risk stratification – distal pancreatectomy with splenectomy and observation, respectively. An up-to-date literature review on the key points in diagnostics, indications for surgery, the extent of surgery, follow-up, and prognosis is provided. The tailored approach based on risk stratification is the cornerstone of management. Absolute indications for surgery are the lesions with high-risk stigmata, whereas the worrisome features should be evaluated by endoscopic ultrasound and fine-needle aspiration. Main duct and mixed type are usually referred to surgery, whereas the management of a branch type is more conservative due to the lower rate of invasive cancer. Strict postoperative follow-up is mandatory even in negative resection margins due to a high risk for recurrences and metachronous lesions. Despite the guidelines, the intraductal papillary mucinous neoplasm remains a major challenge for clinicians and surgeons in the balance the risk/benefit of observation versus resection. Risk stratification plays a key role in decision-making. Future trials need to determine the optimal period of surveillance and the most reliable predictive factors for concomitant pancreatic duct cancer.

Prognostic Analysis of Different Metastatic Patterns in Invasive Intraductal Papillary Mucinous Neoplasm: A Surveillance, Epidemiology, and End Results Database Analysis

Objective. To evaluate the impacts of different metastatic patterns on the prognosis of patients with invasive intraductal papillary mucinous neoplasm (IPMN). Materials and Methods. All patients who were diagnosed with invasive IPMN in the Surveillance, Epidemiology, and End Results SEER database (2010–2015) were included in this study. They were grouped according to different metastatic patterns. Kaplan–Meier analysis and log-rank test were used for the comparison of their survival rates. The hazard ratio (HR) with 95% confidence interval (CI) was analyzed using the Cox proportional-hazards model. Results. A total of 2264 cases were included in this study. The most common metastatic site was the liver. The patients with the nonorgan metastasis demonstrated the best survival outcomes, while those with multiple metastases showed the worst survival outcomes. As compared to the patients with isolated liver metastasis, those with isolated lung and other organ metastases showed better overall survival rates and tumor-specific survival rates. The patients with liver, lung, multiple, and other organ metastases or of age >60 years were the independent predictors of poor prognosis. Conclusions. The patients with isolated lung and other organ metastases demonstrated better survival outcomes as compared to those with isolated liver metastasis. The patients with nonorgan metastasis demonstrated the best survival outcomes, while those with multiple metastases showed the worst survival outcomes. Further studies are needed to determine a highly selected subset of patients, who might benefit from surgery or chemotherapy.

Pancreatic medullary carcinoma developed on a pancreatic intraductal papillary mucinous neoplasm with loss of MSH2 and MSH6 expression: a case report

Background Pancreatic medullary carcinoma (PMC) is a rare pancreatic tumor, usually showing the presence of microsatellite instability, mostly MLH1 silencing, and a wild-type KRAS mutation status. We report here a PMC arising from a Pancreatic Intraductal Papillary Mucinous Neoplasm (IPMN), both having KRAS and TP53 mutations. Case presentation We report the case of a 73-year-old woman presenting with right iliac fossa pain. MRI revealed a 16 mm diameter mass in the pancreas, leading to a pancreatic duct stricture and upstream a dilatation of the distal pancreatic duct of Wirsung. A fine needle aspiration was performed, and pathology analysis revealed malignant glandular cells. The patient underwent distal pancreatectomy. Gross examination revealed an12 mm indurated white lesion, adjacent to a cystic lesion extending into the rest of the pancreatic body. Microscopically, the cystic area represented a mixed (gastric-type and pancreatobiliary-type) IPMN, involving the main and secondary pancreatic ducts with low-grade and high-grade dysplasia. In the periphery of this IPMN, a 14mm associated invasive carcinoma was observed, characterized by focal gland formation and by poorly differentiated cells with a syncytial appearance, associated with a dense lymphoplasmocytic and neutrophilic infiltrate. Immunohistochemical analyses showed loss of MSH2 and MSH6 expression. Microsatellite instability was confirmed by molecular test. Molecular analysis was performed both on the invasive carcinoma and on the high-grade dysplasia IPMN, revealing the same mutation profile with KRAS and TP53 mutations. The proposed diagnosis was mixed IPMN with associated invasive medullary carcinoma that presented loss of MSH2 and MSH6 expression. Conclusions The present case reports for the first time, at the best of our knowledge, the coexistence of IPMN lesions and PMC, both having the same molecular alterations. It also describes the second case of PMC with microsatellite instability, MSH2 and MSH6 silenced.