Page 32 - Noninvasive Diagnostic Techniques for the Detection of Skin Cancers

CSLM images can be evaluated in detail for the diagnosis of skin cancer and characterization of
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lesions.
Confocal microscopy images are in grayscale, therefore structures with higher reflectance are
bright over a dark background. Standardized terminology for the evaluation of reflectance of
confocal microscopy images was developed at an online consensus meeting between 2004 and
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2005 and subsequently published. Although initial models of CSLM were bulky, hand held
confocal devices are now available.

Theoretical Advantages
Compared with other noninvasive modalities, the major strength of CSLM is the capability to
produce high resolution images of cellular components with precision close to that of histology.
Several studies in lentigo maligna melanoma, amelanotic melanoma and diagnostic accuracy in
equivocal lesions by dermatoscopy pointed out the clinical use of confocal microscopy in the
examination of suspicious lesions. 83-86 Our key informants remarked that this technology may
present an opportunity to obtain the same information as a histopathological diagnosis without
performing a biopsy, especially for initial screening.
At long wavelengths, papillary dermis can be accessed. In addition, the images can be used in
tele-pathology with certain commercially available data storage and transfer systems.
Furthermore, confocal microscopes do not have direct contact with the skin under evaluation.

Theoretical Disadvantages
Despite its various theoretical advantages, CSLM is not without limitations. First, the high
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cost of confocal microscopes is an obstacle to the widespread diffusion of this technique.
Second, compared with conventional histology, CSLM images have poorer resolution of
microscopic structures including chromatin patterns, nuclear contours, and nucleoli, and
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therefore, deeper structures, located in the reticular dermis, cannot be examined. Third, CSLM
images allow evaluation of micro-anatomical structures of about 300 µm only, again limiting
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examination to the upper dermal layers.

Variations of Technique
• Confocal scanning laser microscopy. This type can be in either reflectance or
fluorescence mode. In reflectance CSLM, laser-illuminated tissue structures and melanin
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reflect light toward the confocal microscope detector. It is more commonly used in a
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clinical setting, and can be either diffuse or polarized. In fluorescence CSLM, a laser
beam excites the endogenous or exogenous fluorescent molecules, which emit the signals
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to the confocal microscope detector. Fluorescence CSLM is used primarily in research.
• One manufacturer, Lucid, Inc., produced three models of confocal microscopes. The
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newest model, called VivaScope 3000, is a handheld device, which overcomes the size
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limitations in the previous models. Lucid also developed the VivaNet Digital Imaging
and Communications in Medicine, which allows storage and transfer of confocal
microscopy images among healthcare providers in different geographic locations.
According to a general review, Optiscan Pty. Ltd. also manufactures confocal
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microscopes, named Optiscan.™

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