Fluorescein-aided probe-based confocal laser endomicroscopy (pCLE) for detection of lung cancer

Objectives: We investigated the capabilities of a probe-based confocal laser endomicroscopy (pCLE) that enables microscopic imaging of the tracheobronchial tree including peripheral lung tumor during bronchoscopy after administration of 10% fluorescein. Methods: Nine patients with suspected lung cancer were underwent bronchoscopy with pCLE using fluorescein. CLE probes were selected both Alveoflex probe 1.4mm in diameter for the peripheral lung tumor and Gastroflex probe 2.5mm in diameter for the central airways tumor. Following localization of peripheral lung tumor with endobronchial ultrasonography-guided sheath (EBUS-GS) and of central airways tumor with white light, narrow band imaging (NBI) and autofluorescence imaging (AFI) bronchoscopy, pCLE was performed followed by bronchoscopic tumor biopsy. Histological examinations using haematoxylin and eosin staining were made of biopsied specimens. Analyzed pCLEimages were compared with the corresponding histological examinations. Results: Of the 9 patients, 5 adenocarcinomas and 2 squamous cell carcinomas were identified pathologically. In adenocarcinoma, confocal images demonstrated large, irregular, dark tumor cells were visible and abnormal structures were also similar to acinar differentiated types. In squamous cell carcinoma, large, polymorphic tumor cells showed increased cellular densities with irregular stratified patterns and capillary blood vessels, tumor vessels with flow of red blood cells also visible. Conclusion: pCLE was useful for the detection malignant tumor cells during bronchoscopy in real time. This novel technology has an excellent potential to provide in vivo diagnosis during bronchoscopic examinations.