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

Transabdominal ultrasonographic diagnosis of relatively rare pancreatic neoplasms

There are various types of pancreatic neoplasms, and their prognosis and treatment methods are different. Therefore, accurate diagnosis is important to determine the best treatment strategy. Transabdominal ultrasonography is frequently used as a screening examination for diagnostic imaging of pancreatic neoplasms. In this review, we have focused on the characteristics of ultrasonic findings for relatively rare pancreatic neoplasms.

Management of pancreatic cysts and guidelines: what the gastroenterologist needs to know

The prevalence of pancreatic cysts has increased significantly over the last decade, partly secondary to increased quality and frequency of cross-sectional imaging. While the majority never progress to cancer, a small number will and need to be followed. The management of pancreatic cysts can be both confusing and intimidating due to the multiple guidelines with varying recommendations. Despite the differences in the specifics of the guidelines, they all agree on several high-risk features that should get the attention of any clinician when assessing a pancreatic cyst: presence of a mural nodule or solid component, dilation of the main pancreatic duct (or presence of main duct intraductal papillary mucinous neoplasm), pancreatic cyst size ⩾3–4 cm, or positive cytology on pancreatic cyst fluid aspiration. Other important criteria to consider include rapid cyst growth (⩾5 mm/year), elevated serum carbohydrate antigen 19-9 levels, new-onset diabetes mellitus, or acute pancreatitis thought to be related to the cystic lesion.

Nonmucinous Cystic Lesions of the Pancreas

CONTEXT.—

Pancreatic cystic lesions are increasingly diagnosed. Among other criteria, they are often distinguished in mucinous versus nonmucinous cysts. Mucinous pancreatic cystic lesions have received increasing attention, especially those known as precursors of pancreatic ductal adenocarcinoma. However, the group of nonmucinous cystic lesions of the pancreas includes numerous entities that may pose a diagnostic challenge. Their accurate diagnosis and classification are crucial for adequate patient management.

OBJECTIVE.—

To review the spectrum of nonmucinous cystic lesions of the pancreas, taking into consideration their epidemiology and typical clinical context, their characteristic gross morphology and histomorphology, as well as their immunohistochemical and molecular profile.

DATA SOURCES.—

Literature was searched and reviewed with MEDLINE via PubMed. Macroscopic and microscopic images were obtained from the archives of the Institute of Pathology, Heinrich Heine University and University Hospital of Duesseldorf, Germany.

CONCLUSIONS.—

Nonmucinous cysts of the pancreas comprise numerous, mostly rare entities displaying different biological behaviors. The most frequent are serous cystic neoplasms, solid-pseudopapillary neoplasms, cystic neuroendocrine tumors, and pancreatitis-associated pseudocysts. Accurate diagnosis can be achieved if characteristic clinical context, histomorphology, and immunoprofile are taken into account.

Current indications and yield of endoscopic ultrasound and ancillary techniques in pancreatic cystic neoplasms

An increase in the diagnosis of pancreatic cystic neoplasm has been described lately. Surgical treatment or surveillance is advised depending on the type of lesion diagnosed. The most accurate diagnostic approach is needed to make the best therapeutic decision. Endoscopic ultrasound is a very valuable tool in the evaluation of pancreatic cystic neoplasm. It generates high-quality images and allows the possibility of sampling the cystic fluid for cytology, microbiological and molecular evaluation. Even with this evaluation, the sensitivity of this approach is not always adequate. New technological resources have been developed to try to improve the diagnostic accuracy of pancreatic cystic neoplasms. The two most promising techniques are needle-based confocal laser endomicroscopy and contrast-enhanced harmonic endoscopic ultrasound. Needle-based confocal laser endomicroscopy allows a microscopic evaluation of mucosal glands and vascular pattern, to differentiate mucinous from non-mucinous lesions. Contrast-enhanced harmonic endoscopic ultrasound is used for the vascular evaluation of the microcirculation of the cyst wall and mural nodule, mainly to make the difference between malignant nodules and mucus plugs. A combination of these different diagnostic techniques can improve the diagnostic accuracy of pancreatic cystic neoplasms to offer the adequate therapeutic decision.

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.

Imaging of pancreatic neuroendocrine tumors: recent advances, current status, and controversies

INTRODUCTION

Recently, there have been a number of advances in imaging pancreatic neuroendocrine tumors (panNETs), as well as other neuroendocrine tumors (NETs), which have had a profound effect on the management and treatment of these patients, but in some cases are also associated with controversies. Areas covered: These advances are the result of numerous studies attempting to better define the roles of both cross-sectional imaging, endoscopic ultrasound, with or without fine-needle aspiration, and molecular imaging in both sporadic and inherited panNET syndromes; the increased attempt to develop imaging parameters that correlate with tumor classification or have prognostic value; the rapidly increasing use of molecular imaging in these tumors and the attempt to develop imaging parameters that correlate with treatment/outcome results. Each of these areas and the associated controversies are reviewed. Expert commentary: There have been numerous advances in all aspects of the imaging of panNETs, as well as other NETs, in the last few years. The advances are leading to expanded roles of imaging in the management of these patients and the results being seen in panNETs/GI-NETs with these newer techniques are already being used in more common tumors.

Author´s reply: Cystic pancreatic neuroendocrine tumors. A diagnostic challenge

We are grateful for the helpful comments of Varas et al. with regard to the phenotype of cystic pancreatic neuroendocrine tumors (CPNT) reported in a recent meta-analysis of 436 patients. Varas et al. highlight the lower incidence of CPNT diagnosed incidentally in 135 patients (44.6%) in comparison with a recent series of 49 patients with an incidental tumor diagnosis of 56.5%.

Cystic pancreatic neuroendocrine tumor. Pancreatic endocrine or neuroendocrine tumor. Endoscopic ultrasonography

Cystic pancreatic neuroendocrine tumors (cPNETs) represent less than 8% of all pancreatic cysts and approximately 13% of pancreatic endocrine tumors (PNETs). According to a recent review, the percentage of non-functional (NF) PNETs is 85% and 44.6% are incidentalomas. In our series of 75 PNET cases, ten cPNET cases (13%) were identified which are discussed and summarized below.