The purpose of this study is to compare the diagnostic gain between 22G standard needle vs 19G Flex needles transduodenal punctures of masses of the pancreatic head.

The negative predictive value of fine needle aspiration under ultrasound endoscopy (EUS-FNA) for the diagnosis of solid pancreatic masses is about 70 - 80 % with the 22G standard needle. Pancreatic adenocarcinoma is known to have a severe prognosis and a low rate of survival even after curative surgery. The study of pancreatic solid tumors is one the main diagnostic problem present in the investigators daily practice. In most of non operated patients, EUS-FNA is the sole possibility to confirm the diagnosis of malignancy which is required to initiate chemotherapy and/or radiotherapy. To improve the performances of the EUS-FNA, new needles are now disposable either with a cutting window design (EchoTip ProCore-COOK Medical) or flexible 19G needle (19G Expect Flex - Boston-Scientific). The goal is to obtain more tissue material with the possibility of a histologic study without increasing the risk of the puncture which is very low (complications rate < 1%). The problem concerns the lesion of the head of the pancreas requiring a trans-duodenal access for the puncture . In this position, the needle is very difficult to push out the operator channel and, in some cases, the puncture is quite impossible with stiff needles as "ProCore" or standard 19G. Thus, the interest of flexible 19G needle is to be used in difficult technical cases as transduodenal access for head pancreatic tumors, with a good safety and more efficacy than 22G needles.

Inclusion Criteria:

• patient with solid tumor of pancreas who has to receive a biopsy under endoscopic ultrasound (EUS)
• patient who understands the study procedures, risks and voluntarily agrees to participate by giving written informed consent

Exclusion Criteria:

• patient who participates in an other study
• patient mentally or legally incapacitated
• patient with contraindications to the achievement of upper gastrointestinal endoscopy
• patient with haemorrhagic disease, disorder of hemostasis and coagulation (TP<60%, TCA>40sec and platelets <60000/mm3)
• patient with anticoagulant or antiaggregating treatment that could not be stopped for the endoscopic procedure
• patient with pancreatic cystic mass (fluid quota valued at more than 50% of the mass lesion on imaging)
• patient pregnant or lactating women