Confocal Laser Endomicroscopy in Precancerous Lesions of the Head and Neck

Abstract

Objectives: Distinguishing precancerous lesions from invasive carcinoma is a challenge due to field cancerization. Extensive biopsies are required to determine histology and sampling errors result in inaccurate diagnosis. The probe based confocal laser endomicroscopy (pCLE) is an emerging technology of real time microscopic imaging of mucosal surfaces at the cellular level. It has been studied extensively in the lung and gastrointestinal tract but not the head and neck. Methods: We performed a study on awake patients with 15 precancerous and cancerous lesions of the oral cavity. After intravenous injection of fluorescein, a 1.8-mm gastroflex probe helped visualize normal mucosa, carcinoma, and precancer to assess image quality on various grades of dysplasia. The histology from biopsies of visualized areas was compared to optical images. Results: The dorsal surface of the tongue was not well visualized due to the keratinized filiform papillae. The remaining non-keratinized subsites, buccal mucosa, floor of mouth, and ventral tongue were well visualized. Although leukoplakia was widespread, only some areas demonstrated suspicious microarchitecture, including abnormal vasculature and disruption of membranes. This correlated with final histology. Flat, well-organized scale-like cells were noted in normal mucosa. In patients with carcinoma in situ there were increased ectatic blood vessels. In high grade dysplasia there was complete disorganization of the epithelium and fluorescein leakage with an abrupt change to the so called “black cells.” Conclusions: The pCLME has significant potential in determining areas more likely to progress to carcinoma, resection margins in head and neck squamous cell carcinoma patients plagued with field cancerization, and response to chemopreventive agents.