Endoscopic transesophageal fine needle aspiration of mediastinal masses

With the introduction of EUS, endoscopy was no longer limited to luminal indications. However, the method was unable to distinguish malignant from benign lesions. Consequently, needles designed for tissue acquisition under EUS-guidance was designed. Initially, the needles were designed for fine needle aspiration (FNA); nevertheless, with increased requirement for the precured tissue in terms of quality and quantity, newly design needles aimed at obtaining tissue cores for histological assessment were developed. Recent studies demonstrate superiority of these fine needle biopsy needles (FNB) compared to FNA needles.

The development of endoscopy is a testimony to human ingenuity. Instruments have evolved from dangerous straight tubes, illuminated by light reflected from candles, to more flexible and safer instruments with an image transmitted through a series of prism lenses and illumination by an electric light bulb, to images transmitted through fiberoptic bundles with illumination transmitted by fiber bundles from an external source, to our present remarkably safe electronic instruments with digital images transmitted to a video screen through wires and processed by computers. Most recently, we can visualize the lumen of the gut without touching the patient. Now we not only can visualize, biopsy tissue, and perform procedures within the hidden cavities of the body, but also directly and indirectly see beneath the mucosa and into immediately adjacent organs. The evolution of gastrointestinal endoscopy is a truly remarkable story, and advances in the diagnostic and therapeutic capabilities of these instruments continue to be made at a rapid pace. To know and understand what has occurred previously lends strength to efforts toward achieving what is to come.

The use of endoscopic ultrasound (EUS) has grown over the last 25 years, and it is now a well-established diagnostic method for luminal and extraluminal disorders. This chapter discusses EUS applications relating to extraintestinal structures, organs, and lesions. The objectives of this chapter are to review the utility of EUS for evaluating the mediastinum in both benign and malignant disease processes, including the detection of mediastinal lymph node metastases in lung cancer. Mass lesions in the paragastric and retroperitoneal organs (excluding the bile duct, gallbladder, and pancreas) are reviewed, including detection of lesions of the adrenal gland, liver, and kidneys. Ascites and pleural fluid are examined along with unusual extraintestinal lesions.