Differentiating pancreatic neuroendocrine tumors from pancreatic ductal adenocarcinomas by the "Duct-Road Sign": A preliminary magnetic resonance imaging study

Pancreatic neuroendocrine tumour resection in circumportal pancreas: a rare anatomical anomaly with important surgical implications

Various congenital anomalies of the pancreas have been reported due to its complex embryological development involving the fusion of two separate buds. Circumportal pancreas is a rare anatomical anomaly where the pancreatic head and uncinate process fuse abnormally with the pancreatic body, encasing the portal vein and/or superior mesenteric vein completely. This anomaly poses several challenges to hepatobiliary surgeons, as the encasement of the portal vein by the abnormal pancreatic tissue makes an additional parenchymal transection necessary. Vascular variants have also been reported with circumportal pancreas, which, if not recognised preoperatively, can be catastrophic. Therefore, careful preoperative evaluation and planning are essential, to ensure safe pancreatic resection and recovery in a patient with circumportal pancreas. We present a case of a successful subtotal pancreatectomy and splenectomy in a patient with circumportal pancreas, for a suspected pancreatic duct adenocarcinoma. The aim of this case report is to contribute valuable insights that can aid hepatobiliary surgeons in enhancing their preoperative planning when encountered with patients with similar anatomical variances.

A Rare Case of a Pancreatic Intraductal Oncocytic Papillary Neoplasm Associated With Invasive Adenocarcinoma Presenting as a Gastric Mass

The World Health Organization recently recognized intraductal oncocytic papillary neoplasms of the pancreas (IOPNs) as distinct, pre-malignant pancreatic neoplasms. Due to their unique macroscopic and microscopic features, IOPNs are typically easy to diagnose and yield an indolent prognostic outcome. The diagnosis may be more complicated, and the prognosis may differ if an associated invasive carcinoma is present. Owing to the rarity of this entity, the available data is severely limited. Herein, we report a diagnostically challenging case of an IOPN associated with invasive carcinoma, initially presenting as a gastric mass with distinctive radiological and histopathological features.

MRI Feature-Based Nomogram Model for Discrimination Between Non-Hypervascular Pancreatic Neuroendocrine Tumors and Pancreatic Ductal Adenocarcinomas

This study aimed to investigate whether magnetic resonance imaging (MRI) features could differentiate non-hypervascular pancreatic neuroendocrine tumors (PNETs) from pancreatic ductal adenocarcinomas (PDACs). In this study, 131 patients with surgically and pathologically proven non-hypervascular PNETs (n = 44) or PDACs (n = 87) were enrolled. Two radiologists independently analyzed MRI imaging findings and clinical features. Relevant features in differentiating non-hypervascular PNETs from PDACs were identified via univariate and multivariate logistic regression models. The MRI feature-based nomogram was constructed based on multivariable logistic analysis and the reliability of the constructed nomogram was further validated. The results showed that tumor margin (P = 0.012; OR: 6.622; 95% CI: 1.510, 29.028), MPD dilation (P = 0.047; OR: 4.309; 95% CI: 1.019, 18.227), and signal in the portal phase (P < 0.001; OR: 53.486; 95% CI: 10.690, 267.618) were independent discriminative MRI features between non-hypervascular PNETs and PDACs. The discriminative performance of the developed nomogram was optimized compared with single imaging features. The calibration curve, C-index, and DCA validated the superior practicality and usefulness of the MRI-based nomogram. In conclusion, the radiologically discriminative model integrating various MRI features could be preoperatively and easily utilized to differentiate non-hypervascular PNETs from PDACs.

Pancreatic Neuroendocrine Neoplasms: 2020 Update on Pathologic and Imaging Findings and Classification

Pancreatic neuroendocrine neoplasms (panNENs) are heterogeneous neoplasms with neuroendocrine differentiation that show characteristic clinical, histomorphologic, and prognostic features; genetic alterations; and biologic behavior. Up to 10% of panNENs develop in patients with syndromes that predispose them to cancer, such as multiple endocrine neoplasia type 1, von Hippel-Lindau disease, tuberous sclerosis complex, neurofibromatosis type 1, and glucagon cell adenomatosis. PanNENs are classified as either functioning tumors, which manifest early because of clinical symptoms related to increased hormone production, or nonfunctioning tumors, which often manifest late because of mass effect. PanNENs are histopathologically classified as well-differentiated pancreatic neuroendocrine tumors (panNETs) or poorly differentiated pancreatic neuroendocrine carcinomas (panNECs) according to the 2010 World Health Organization (WHO) classification system. Recent advances in cytogenetics and molecular biology have shown substantial heterogeneity in panNECs, and a new tumor subtype, well-differentiated, high-grade panNET, has been introduced. High-grade panNETs and panNECs are two distinct entities with different pathogenesis, clinical features, imaging findings, treatment options, and prognoses. The 2017 WHO classification system and the eighth edition of the American Joint Committee on Cancer staging system include substantial changes. Multidetector CT, MRI, and endoscopic US help in anatomic localization of the primary tumor, local-regional spread, and metastases. Somatostatin receptor scintigraphy and fluorine 18-fluorodeoxyglucose PET/CT are helpful for functional and metabolic assessment. Knowledge of recent updates in the pathogenesis, classification, and staging of panNENs and familiarity with their imaging findings allow optimal patient treatment. ^©RSNA, 2020.