 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. 