Intraductal papillary mucinous neoplasm of the pancreas: Cytomorphology, imaging, molecular profile, and prognosis

Rare Non-Neuroendocrine Pancreatic Tumours

The most common tumour of the pancreas is ductal adenocarcinoma (PDAC). It remains one of the most lethal non-neuroendocrine solid tumours despite the use of a multi-approach strategy. Other, less-common neoplasms, which are responsible for 15% of pancreatic lesions, differ in treatment and prognosis. Due to the low incidence rate, there is a lack of information about the rarest pancreatic tumours. In this review, we described six rare pancreatic tumours: intraductal papillary mucinous neoplasm (IPMN), mucinous cystadenoma (MCN), serous cystic neoplasm (SCN), acinar cell carcinoma (ACC), solid pseudopapillary neoplasm (SPN) and pancreatoblastoma (PB). We distinguished their epidemiology, clinical and gross features, covered the newest reports about courses of treatment and systematised differential diagnoses. Although the most common pancreatic tumour, PDAC, has the highest malignant potential, it is still essential to properly classify and differentiate less-common lesions. It is vital to continue the search for new biomarkers, genetic mutations and the development of more specific biochemical tests for determining malignancy in rare pancreatic neoplasms.

The basics of commonly used molecular techniques for diagnosis, and application of molecular testing in cytology

Molecular diagnostics has expanded to become the standard of care for a variety of solid tumor types. With limited diagnostic material, it is often desirable to use cytological preparations to provide rapid and accurate molecular results. This review covers important pre-analytic considerations and limitations, and a description of common techniques that the modern cytopathologist should understand when ordering and interpreting molecular tests in practice.

Case report: Treatment of intraductal papillary mucinous neoplasms located in middle-segment pancreas with end-to-end anastomosis reconstruction after laparoscopic central pancreatectomy surgery through a pigtail-tube-stent placement of the pancreatic duct

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is one type of pancreatic cystic neoplasm. IPMNs can be classified into three types: main duct-IPMN (MD-IPMN), branch duct-IPMN (BD-IPMN), and mixed type-IPMN (MT-IPMN). It is universally accepted by most surgeons that patients who suffered from MD-IPMN with a high risk of malignant transformation should undergo surgical resection. However, a consensus on the best surgical strategy for MD-IPMN located in the pancreatic neck has still eluded the surgical community worldwide. Recently, one patient suffering from this condition in our Minimally Invasive Pancreas Center underwent a successful surgical procedure. In this case report, we performed a laparoscopic central pancreatectomy for this patient. During this surgical procedure, we used a method of end-to-end anastomosis reconstruction through a pigtail-tube-stent placement of the pancreatic duct. Before the construction of the remnant pancreas, the surgical margins of the frozen section should be negative. After surgery, the outcome of this case was satisfactory. No complications such as postoperative hemorrhage, abdominal infection, pancreatitis, delayed gastric emptying, and clinically relevant postoperative pancreatic fistula occurred, which demonstrated that this surgical strategy could achieve a good clinical therapeutic effect for the pancreatic neck MD-IPMN. The result of postoperative routine pathology confirmed the diagnosis of MD-IPMN. The pathological features also showed that there was a high degree of hyperplasia in the local epithelium, which indicated the necessity of surgical treatment.

Background features in the cytology of pancreatic neoplasms

Cytology is a useful method for diagnosing pancreatic neoplasms. Although endoscopic ultrasound‐guided fine‐needle aspiration has recently become the mainstream method for the diagnosis of pancreatic neoplasms, pancreatic juice and pancreatic duct brushing cytology continue to be useful diagnostic methods for the investigation of pancreatic neoplasms. Diagnoses using pancreatic cytology are primarily based on the features related to tumor cells; however, evaluation of the background features provides important information that could further aid the diagnosis. Pancreatic neoplasms show various histological types, each of which is associated with its own characteristic background features. The necrotic background, desmoplastic stroma, and presence of cancer‐associated fibroblasts are background features of pancreatic ductal adenocarcinoma, a mucinous background is associated with intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, and hyaline globules are observed in solid pseudopapillary neoplasms. However, some background features are associated with more than one histological type of pancreatic neoplasm, highlighting the importance to base a diagnosis on the results of a comprehensive analysis of not only the background features but also the tumor cells. Here, we provide a review of the key background cytological features of pancreatic neoplasms, which can serve as a guide to improve diagnosis and research.