Diagnosis of head and neck precancerous lesions in an animal model using fluorescence spectroscopy.

Laser-induced fluorescence (LIF) of tissues depends on their biochemical and histomorphologic characteristics. LIF spectroscopic properties of 9,10-dimethyl-1,2-benzanthracene (DMBA)-induced precancerous and early cancerous lesions in a hamster buccal pouch mucosa model were studied. Fluorescence spectra from neoplastic lesions showed a characteristic fluorescence peak in the red region of the visible spectrum centered between 630 and 640 nm when excited with 410-nm light. Using this as a diagnostic criterion, 45 of 49 lesions studied were correctly diagnosed, including early dysplastic lesions. Follow-up study of four dysplastic lesions over 2 weeks revealed an increase in red fluorescence intensity. The findings of these experiments suggest that LIF spectroscopy may be a valuable noninvasive technique not only for early diagnosis of head and neck cancer, but also to probe a possible biochemical surrogate biomarker in the follow-up of suspected lesions.

Autofluorescence characteristics of oral mucosa.

BACKGROUND: The fluorescence characteristics of tissues depend upon their biochemical composition and histomorphological architecture, both of which undergo a change during malignant transformation. These changes are detectable as an alteration in the fluorescence spectral profile of the tissues. METHODS: Biopsy specimens from clinically suspicious lesions and normal-appearing oral mucosa were obtained from patients. Fluorescence spectroscopic measurements were obtained to study the differences between normal and dysplastic tissues and to determine the most appropriate excitation wavelength(s) for exploiting these differences. RESULTS: Fluorescence spectra from a total of 12 histologically normal (healthy mucosa or benign lesions) and ten abnormal (dysplastic or malignant) tissue samples were compared. Significant spectral differences were seen between the two groups. These differences were most marked at the excitation wavelength of 410 nm. Using this wavelength, fluorescence correctly diagnosed 20 of 22 samples studied. CONCLUSIONS: This technique accurately differentiates normal from abnormal tissues in vitro and has the potential applications for in vivo use as a noninvasive diagnostic tool.

Early diagnosis of upper aerodigestive tract cancer by autofluorescence.

OBJECTIVE: To explore the potential of autofluorescence spectroscopy as a tool for early detection of upper aerodigestive tract cancer. DESIGN: Autofluorescence spectral characteristics of 19 untreated oral and oropharyngeal lesions in 13 patients were studied with excitation wavelengths of 370 and 410 nm generated by a nitrogen pumped dye laser. Ten healthy volunteers were recruited to characterize the fluorescence spectra of normal mucosa at different oral sites and to study individual variations. Fluorescence intensity and line shape of the spectra from lesions were compared with the same parameters from the contralateral control site in the same individual. SETTING: Otolaryngology Research Center, Department of Otolaryngology-Head and Neck Surgery, New England Medical Center, Boston, Mass. RESULTS: The ratio of peak fluorescence intensities of the neoplastic lesions to contralateral normal control mucosa were consistently different compared with these ratios in benign lesions or normal mucosa. These differences were seen in 2 distinct regions of the fluorescence spectrum with both of the excitation wavelengths, but were more obvious with the excitation wavelength of 410 nm. Using these differences, we were able to correctly diagnose 17 of the 19 lesions studied, with 2 false-positive results. CONCLUSIONS: Neoplastic oral mucosa shows consistent differences in autofluorescence spectral intensity and line shape when compared with the normal mucosa in the same individual. These early results show that fluorescence spectroscopy may represent a useful technique for noninvasive early diagnosis of cancer of the upper aerodigestive tract.

Multiple oncocytic cysts of the larynx.

Oncocytic metaplasia in laryngeal epithelium is uncommon. Oncocytes have been described in the lining of laryngeal cysts and such cysts have been reported in the literature under a variety of names. There is an ongoing debate about the exact nature of 'oncocytic cysts', which tend to be solitary. An unusual case of multiple oncocytic cysts of the larynx is described. The pathology and treatment are discussed.