Diagnostic potential of fluorescence of formalin-fixed paraffin-embedded malignant melanoma and pigmented skin lesions: quantitative study of fluorescence intensity using fluorescence microscope and digital imaging.

The background for this study was reports in the literature of stronger fluorescence observed visually for melanomas compared with benign naevi in formalin-fixed paraffin-embedded sections. Our objective was to carry out a quantitative study of the phenomenon and to investigate if such an approach could be used in the detection of melanomas. Microscopic digital imaging was used to measure quantitatively the fluorescence intensity in specimens from 50 malignant melanomas, four basal cell carcinomas and 58 benign lesions. The mean fluorescence intensity of the melanomas was considerably higher than of the other lesions. For melanomas, the intensity depended both on the distance from the skin surface and the distance from the centre of the lesion. A simple algorithm based on the intensity threshold correctly classified the melanomas with a sensitivity of 74% and a specificity of 59%. Quantitative measurements of the fluorescence of the pigmented skin lesions fixed with formalin and embedded in paraffin can be a useful auxiliary tool for differentiating melanoma from other pigmented lesions histopathologically.

Fluorescence in situ detection of human cutaneous melanoma: study of diagnostic parameters of the method.

Multicenter study of the diagnostic parameters was conducted by three groups in Poland to determine if in situ fluorescence detection of human cutaneous melanoma based on digital imaging of spectrally resolved autofluorescence can be used as a tool for a preliminary selection of patients at increased risk of the disease. Fluorescence examinations were performed for 7228 pigmented lesions in 4079 subjects. Histopathologic examinations showed 56 cases of melanoma. A sensitivity of fluorescence detection of melanoma was 82.7% in agreement with 82.5% found in earlier work. Using as a reference only the results of histopathologic examinations obtained for 568 cases we found a specificity of 59.9% and a positive predictive value of 17.5% (melanomas versus all pigmented lesions) or 24% (melanomas versus common and dysplastic naevi). The specificity and positive predictive value found in this work are significantly lower than reported earlier but still comparable with those reported for typical screening programs. In conclusion, the fluorescence method of in situ detection of melanoma can be used in screening large populations of patients for a selection of patients who should be examined by specialists.

Spectrally resolved fluorescence imaging of human colonic adenomas.

Native fluorescence (autofluorescence) of human tissues can be a valuable source of diagnostic information for detecting premalignant and malignant lesions in the human body. Digital imaging of autofluorescence may be useful for localization of such lesions during endoscopic examinations. Tissue fluorescence of 31 adenomatous polyps obtained from 16 patients has been excited in vitro using the 325 nm line of a He-Cd laser. Digital images of the autofluorescence are recorded in six spectral bands. This study provides new data about the spatial distributions of autofluorescence intensities emitted in different spectral bands by colonic adenomatous lesions and normal colonic mucosa. Areas characterized by autofluorescence intensity lower than in normal mucosa are found for a majority of the polyps under study. The observed patterns of spatial distribution differ for the different spectral bands and for different polypoid lesions. No inverse correlation is found between the emission intensity and the thickness of colonic mucosa. The results indicate the spectral bands most useful for diagnostic applications and demonstrate the complexity of the optical processes involved in shaping both the spectra and intensities of the autofluorescence.