Confocal endomicroscopy is an emerging technique that allows in vivo imaging of cells and tissue structures of the gastrointestinal mucosa, with a magnification of about 1000 times, guiding optical biopsies in real time. Confocal endomicroscopy represents technique that combines conventional white light image with the confocal microscope probe, thereby allowing examination of the surface epithelium in vivo and histological diagnosis during endoscopy. Among the applications already established for its use, stand out diagnosis of Barrett's esophagus, gastric atrophy and intestinal metaplasia, celiac disease, differentiation of hyperplastic adenomatous polyps of the colon, microscopic colitis and follow-up of patients with inflammatory disease, reducing the need for endoscopic biopsies. The CLE can still detect molecular changes effectively improving the endoscopic diagnosis. This pilot project consists of 07 subprojects which the technology of confocal endomicroscopia will be evaluated and compared with the histological results of biopsy or surgical specimens:

1. confocal endomicroscopy for the diagnosis of high-grade dysplasia and superficial esophageal adenocarcinoma in patients with Barrett's esophagus 2 Diagnosis of superficial esophageal squamous cell carcinoma in patients with head and neck cancer by confocal endomicroscopy 3 Detect the presence of premalignant lesions in the gastric stump in patients with reflux alkaline gastritis after partial gastrectomy 4. detect lesions in the gastric mucosa of patients with familial history of gastric cancer 5 Biliary Strictures: differential diagnosis by confocal endomicroscopia 6 confocal Endomicroscopy of cystic neoplasms of the pancreas 7 Contribution of confocal endomicroscopy for the differential diagnosis of colorectal polyps The project aims to deploy the structure of the Confocal endomicroscopy Endoscopy ICESP, for performing in vivo histological examinations of the digestive tract, biliary tract and pancreas. All research groups involved in the early detection of tumors of the esophagus, stomach, biliary tract, pancreas, colon and rectum may benefit from the implementation of this methodology.

Confocal Endomicroscopy procedure: eligible patients which consent to participate in the study will be submitted to endoscopic procedures under conscious or deep sedation. The patients will receive an intravenous injection of 2.5-5 mL of 10% sodium fluorescein at the beginning of the endoscopic procedure. The endoscope will target the area of interest and the confocal probe will be passed through the endoscope biopsy channel. The probe will gently and perpendicularly touch the mucosal surface of the area of the interest. The images will be recorded and a presumptive diagnosis will be made. The area of interest will be biopsied and the histology results will be considered the diagnostic gold standard method. We will calculate the diagnostic accuracy of the presumptive diagnosis provided by the confocal endomicroscopy examination.

Inclusion Criteria:

• Minimum age of 18 years old
• Clinical conditions for the proposed endoscopic procedure
• Sign the informed consent

Exclusion Criteria:

• History of anaphylactic reactions to fluorescein