 EUS-FNA is performed by passing a needle through a working channel located within the echoendoscope. The needle passes out of the endoscope in the same plane as the ultrasound sensor, allowing the operator to visualize the path of the needle. This allows directed needle puncture of the lesion and avoidance of other structures such as blood vessels. After the needle is passed into the lesion of interest, varying degrees of suction is applied to obtain an aspirate. The needle is withdrawn from the scope channel and aspirate is pushed out of the needle either with a stylet or by using a syringe to pump air to flush out the aspirate for further cyto-pathological evaluation. The cells obtained at needle aspiration can help in differentiating benign from malignant, and also tell the origin of the tumor if malignant. 