Endoscopic ultrasound-guided needle-based confocal laser endomicroscopy for diagnosis of solid pancreatic lesions

Pittayanon, Rapat; Kongkam, Pradermchai; Rerknimitr, Rungsun

Abstract

An accurate diagnosis of solid pancreatic lesions (SPLs) is important because pancreatic cancer cannot be ignored if curative treatment is possible. Prompt and reliable diagnostic procedures are greatly needed for patients presenting with SPLs, particularly where resection is possible for a malignant mass. Several endoscopic ultrasound (EUS)-related technologies including a novel EUS-guided needle-based confocal laser endomicroscopy (EUS-nCLE) can provide real-time images at the cellular level (1,000-fold magnification). A 19-gauge EUS-guided fine needle aspiration (EUS-FNA) needle is recommended because its channel is large enough for the 0.85-mm diameter nCLE miniprobe. The procedure is performed by standard EUS-FNA techniques with either pre- or post-loading technique. Ten percent fluorescein sodium (2.5-5 mL) is used as an enhancing agent and is intravenously injected immediately before puncturing the lesion. Only a few studies have used the technique and reported results. A recent study from 19 malignant and 3 benign SPLs classified EUS-nCLE findings according to 4 signs: dark clumps, and dilated vessels (predominantly seen in malignant SPLs) and fine white fibrous bands and normal acini (predominantly seen in benign SPLs). Using these criteria, researchers correctly diagnosed 18 of the malignant SPLs (94.7%). Another study described 2 lesions as having "dark cells aggregates with pseudo-glandular aspects, and straight hyperdense elements more or less thick corresponding to tumoral fibrosis" in 17 of 18 malignant SPLs. Thus far, no large and systematic study has been performed to evaluate the potential clinical use of EUS-nCLE for diagnosing SPLs. However, based on available information from a few studies and the current limitations of EUS-FNA, EUS-nCLE can potentially provide a complementary role in diagnosing such lesions. Nevertheless, more studies are certainly needed.