Cutting-edge devices evaluate fine nuances of pigmented lesions

June 1, 2013

New and cutting edge technologies are proving useful for clinical diagnosis and early detection of melanoma. Depending on the diagnostic tool used, clinicians can improve their assessment of suspicious lesions and better evaluate the fine nuances differentiating benign and malignant pigmented lesions.

 

Miami Beach, Fla. - New and cutting edge technologies are proving useful for clinical diagnosis and early detection of melanoma. Depending on the diagnostic tool used, clinicians can improve their assessment of suspicious lesions and better evaluate the fine nuances differentiating benign and malignant pigmented lesions.

“The evolution of older as well as the development of new diagnostic tools used in the evaluation of suspicious pigmented lesions has significantly helped us in our efforts for secondary prevention of melanoma,” says Harold S. Rabinovitz, M.D., a dermatologist in private practice and volunteer clinical professor, department of dermatology, University of Miami. “These diagnostic modalities are proving to help in the clinical differentiation of different pigmented lesions, allowing us to more quickly arrive at a correct and timely diagnosis.”

Closer look with dermoscopy

Dermatoscopes remain one of the cornerstone diagnostic tools for the evaluation of suspicious lesions. With the naked eye, dermatologists can reach a diagnostic accuracy for melanoma of about 60 percent, and with dermoscopy, that accuracy can be increased to about 80 percent, Dr. Rabinovitz says. Different structures in pigmented lesions can be better evaluated depending on the type of dermatoscope used.

Traditional or contact nonpolarized dermatoscopes can more optimally visualize epidermal features such as ridges, milia-like cysts and comedo-like openings characteristic of seborrheic keratosis, as well as regression structures (gray dots/granules) and the blue-white veil often seen in melanoma. But, Dr. Rabinovitz says, newer polarized light dermatoscopes can better visualize other features of melanoma, such as crystalline structures (altered collagen), polymorphous vessels and red areas (secondary to vascular changes).

According to Dr. Rabinovitz, hybrid dermatoscopes are now available on the market and allow you to view all of these different yet summarily critical features from one single device. Depending on the make, these units allow you to use either contact nonpolarized or polarized light mode by simply pressing a button on the side of the device or by simple clip-on attachments.

“Hybrid devices are very practical and useful in the evaluation of all features present in the lesion. Moreover, toggling between polarized and nonpolarized dermoscopy can help in highlighting specific structures because of the difference in the depth of imaging,” Dr. Rabinovitz says.

RCM enables ‘virtual pathology’

This noninvasive imaging technique allows for the en-face (horizontal plane) visualization of microscopic structures and cellular detail of the epidermis, dermoepidermal junction, and superficial dermis. Reflectance-mode confocal microscopy (RCM) can produce cellular resolution optically sectioned images of tissue, making the images very similar to those seen in sectioned histopathology of specimens, enabling a “virtual pathology” of the viewed lesions, according to Dr. Rabinovitz.

“Reflectance-mode confocal microscopy offers noninvasive high-resolution imaging of the skin, enabling the reconstruction of three-dimensional structures from the obtained images. These images can be extremely useful in the diagnostic work-up of suspicious lesions and can contribute to the decision making process regarding the management of suspect lesions,” Dr. Rabinovitz says.

The principle of RCM is similar to ultrasound, but instead of ultrasound waves, the system is based on the optical reflectivity, he says. In the technique, a point light source is used to illuminate a small spot within the tissue; the light is then reflected from the tissue and conducted through a small pinhole onto a detector.

“RCM is not only helpful in the evaluation of cutaneous lesions such as melanoma, but also with non-melanoma skin cancers and their differential diagnoses, ultimately assisting physicians in reaching an accurate diagnosis which can lead to a quick and appropriate therapy,” Dr. Rabinovitz says.

Multispectral imaging device

A multispectral imaging device can assist the clinician in the early detection and diagnosis of melanoma. This novel hand-held imaging device emits multiple wavelengths of light to capture images of suspicious pigmented skin lesions and extract critical data. The data are then analyzed against proprietary databases of melanomas and benign lesions using sophisticated algorithms in order to produce a recommendation of whether the lesion should be biopsied.

“The real novelty of this technology lies in its ability to see below the skin. While physicians can only see the top surface, multispectral imaging devices see below the skin up to 3.5 mm deep by virtue of multispectral imaging ranging from blue to infrared,” Dr. Rabinovitz says.

Multispectral imaging devices are only intended for lesions that are pigmented, clinically atypical, and between 2 mm and 22 mm in diameter. According to Dr. Rabinovitz, the added value of this multispectral imaging device - which is approved by the Food and Drug Administration - is that their technology is highly tuned to be sensitive to melanoma, and according to the FDA trial study (Monheit G, Cognetta AB, Ferris L, et al. Arch Dermatol. 2011;147(2):188-194), had a higher specificity than the average clinician assessment. This specificity was 9.9 percent for the device compared to 3.7 percent for the participating physician.

“Along with a careful clinical evaluation, these new and evolving technologies can significantly help us in more accurately and timely diagnosing suspicious lesions, and are welcome in our growing armamentarium of diagnostic tools,” Dr. Rabinovitz says.

Disclosures: Dr. Rabinovitz reports no relevant financial interests.