Role of contrast harmonic endoscopic ultrasonography in other pancreatic solid lesions: Neuroendocrine tumors, autoimmune pancreatitis and metastases

Contrast harmonic endoscopic ultrasonography (CH-EUS) is a new technique which allows the dynamic study of the microvascularization of a target tissue. Its application is validated for the diagnosis of pancreatic adenocarcinoma but remains unclear for other solid pancreatic tumors (neuroendocrine tumors [NETs], autoimmune pancreatitis [AIP], metastases). The purpose of this review is to outline the potential role of the CH-EUS in these indications. NETs are typically iso/hyperenhanced at CH-EUS, and a heterogeneous enhancement seems a good predictor of malignancy in neuroendocrine pancreatic tumor. AIP is often iso/hyperenhanced at CH-EUS. Quantitative analysis of time-intensity parameters is promising for the distinction between pancreatic adenocarcinoma and AIP. The appearance of pancreatic metastases at CH-EUS is various depending on the origin of the primary tumor. Data from the literature remain to this day weak to determine the role of the CH-EUS in the management of rare solid tumor of the pancreas (NETs, AIP, and metastases). Specific studies are expected to further clarify the impact of this procedure in this field.