Endoscopic ultrasound guided fine needle aspiration and useful ancillary methods

Abstract

The role of endoscopic ultrasound (EUS) in evaluating pancreatic pathology has been well documented from the beginning of its clinical use. High spatial resolution and the close proximity to the evaluated organs within the mediastinum and abdominal cavity allow detection of small focal lesions and precise tissue acquisition from suspected lesions within the reach of this method. Fine needle aspiration (FNA) is considered of additional value to EUS and is performed to obtain tissue diagnosis. Tissue acquisition from suspected lesions for cytological or histological analysis allows, not only the differentiation between malignant and non-malignant lesions, but, in most cases, also the accurate distinction between the various types of malignant lesions. It is well documented that the best results are achieved only if an adequate sample is obtained for further analysis, if the material is processed in an appropriate way, and if adequate ancillary methods are performed. This is a multi-step process and could be quite a challenge in some cases. In this article, we discuss the technical aspects of tissue acquisition by EUS-guided-FNA (EUS-FNA), as well as the role of an on-site cytopathologist, various means of specimen processing, and the selection of the appropriate ancillary method for providing an accurate tissue diagnosis and maximizing the yield of this method. The main goal of this review is to alert endosonographers, not only to the different possibilities of tissue acquisition, namely EUS-FNA, but also to bring to their attention the importance of proper sample processing in the evaluation of various lesions in the gastrointestinal tract and other accessible organs. All aspects of tissue acquisition (needles, suction, use of stylet, complications, etc.) have been well discussed lately. Adequate tissue samples enable comprehensive diagnoses, which answer the main clinical questions, thus enabling targeted therapy.

Slow-pull and different conventional suction techniques in endoscopic ultrasound-guided fine-needle aspiration of pancreatic solid lesions using 22-gauge needles

“…Application of suction during EUS-FNA has been controversial because it may result in damage to the cell structure and contamination of the blood while increasing cell quantity[ 8 - 10 ]. Different levels of negative pressure were applied to seek a balanced point between specimen quantity and quality.…”

Needle Fracture during Endoscopic Ultrasound-Guided Fine-Needle Aspiration of Suspicious Thoracic Lymph Nodes

“…Many authors have explored the complications associated with EUS-FNA [ 1 – 3 ], but only a few have explored needle malfunctions specifically.…”

“…The most common complications of EUS-FNA are related to pancreatic lesions (pancreatitis, bleeding, and abdominal pain). Rare complications have been noted such as stent malfunction, air embolism, infection, neural and vascular injuries, and tumor cell seeding [ 1 – 3 ]. There are very few studies examining equipment malfunctions.…”

Role of the preoperative usefulness of the pathological diagnosis of pancreatic diseases

“…Especially, among total 123 patients whose EUS-FNA results were inconclusive or negative, fifty-nine had K-ras mutations and were finally diagnosed with PDAC (48%, 59/123)[ 36 ]. In addition, there are several possible means of processing aspirated samples obtained by EUS-FNA for molecular and other ancillary tests[ 37 ].…”