Differential diagnosis in primary and metastatic cutaneous melanoma by FT-Raman spectroscopy

Andrea Fernandes De Oliveira,Lydia Masako Ferreira,Herculano Da Silva Martinho,Ivan Dunshee De Abranches Oliveira Santos,Airton Abrahão Martin,Sidney Bandeira Cartaxo,Renata Andrade Bitar,Mílvia Maria Simões E Silva Enokihara

doi:10.1590/s0102-86502010000500009

Abstract

To qualify the FT-Raman spectral data of primary and metastatic cutaneous melanoma in order to obtain a differential diagnosis. Ten normal human skin samples without any clinical or histopathological alterations, ten cutaneous melanoma fragments, and nine lymph node metastasis samples were used; 105, 140 and 126 spectra were obtained respectively. Each sample was divided into 2 or 3 fragments of approximately 2 mm³ and positioned in the Raman spectrometer sample holder in order to obtain the spectra; a monochrome laser light Nd:YAG at 1064 nm was used to excite the inelastic effect. To differentiate the three histopathological groups according to their characteristics extracted from the spectra, data discriminative analysis was undertaken. Phenylalanine, DNA, and Amide-I spectral variables stood out in the differentiation of the three groups. The percentages of correctly classified groups based on Phenylalanine, DNA, and Amide-I spectral features was 93.1%. FT-Raman spectroscopy is capable of differentiating melanoma from its metastasis, as well as from normal skin.

Highlights

Raman spectroscopy is an optical technique that provides information on the vibrational levels of molecules
With Raman spectroscopy the molecular structure and composition of the material under study is coded as a group of spread light frequency changes
All samples were histologically diagnosed as normal skin

Summary

Introduction

Raman spectroscopy is an optical technique that provides information on the vibrational levels of molecules. Raman spectroscopy has lately been used as an analytical tool in the biochemical characterization of biological tissues, including neoplasias, due to advantages such as its sensitivity to detect small structural changes in the molecules, as well as being a non-invasive test that does not require much preparation in data collection[1,2,3] These molecular changes can assist in the early detection of neoplastic lesions, and in the scanning of lesions that are not clinically detected, by determining the safe margins for the excision of tumors, based on the concept that chemical changes precede the morphologic changes[4]

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Conclusion