The use of fluorescein in pulmonary medicine was described in CLM through bronchoscope.The protocol consists of the injection of 10 ml of 0,25% of sodium fluorescein solution through a venous catheter and immediate rinsing with 10 ml saline solution 0,9%. This differs from ophthalmologic or gastroenterologic protocols as using a diluted solution. Imaging may start 1 minute following the injection and last up to 10 minutes. We expect lower side effects from fluorescein use as those described in retinal angiography. Fluorescein stains the microvasculature, extracellular matrix and cytoplasmic component (but not cell nuclei) of epithelium and diffuses across capillaries into extravascular spaces. CLM with fluorescein can be used to diagnose neoplasia by presenting abnormal vessels (increased size and arborization) . Increased leakage owing to neovascularization may also be diagnosed. On site rapid cytological examination (ROSE) will be the standard for biopsy quality.