What is Dermoscopy?
1. Dermoscopy significantly improves the in vivo diagnostic accuracy of melanoma.
Dermatologists only diagnose 65–80% of melanomas on routine naked-eye examination. For example, in the Oncology Section of the Skin and Cancer Unit of NYU Langone Medical Center the diagnostic accuracy was found to be only 64% (Grin et al., 1990). Dermoscopy improves diagnostic accuracy by 10–27% (Kittler et al., 2002).
2. Dermoscopy can differentiate most lesions of the skin from melanoma.
With naked-eye examination it is not unusual to come upon a pigmented lesion, which has some or all of the clinical attributes of melanoma, but on dermoscopy the lesion can be definitively diagnosed as some other type of cutaneous lesion.
3. Dermoscopy reduces unneeded biopsies.
Studies have shown that the “benign/malignant ratio” of pigmented lesions of the skin is eventually decreased when dermoscopy is used compared with visually unassisted diagnoses (Carli et al., 2004).
4. Basic instrumentation for dermoscopy is affordable.
Compared with some other available instruments used by dermatologists (e.g., reflectance confocal microscopy), dermoscopes are relatively inexpensive, thus making such technology affordable for most practitioners.
5. Dermoscopes are easy to use.
Placing liquid or gel onto the skin prior to placement of the glass plate of the dermoscope onto the lesion allows the clinician to view the lesion, through the magnifying ocular lens of the dermoscope, with exceptional clarity. The liquid interface, by matching the refractive index of the stratum corneum and glass plate, allows the clinician to visualize structures below the surface of the skin. The advent of polarized dermoscopes, however, has eliminated the necessity for a liquid interface or direct skin contact.
6. Several helpful algorithms have been created to aid in classifying lesions of the skin.
These algorithms have been created primarily for those who are beginning to use dermoscopy.
7. Dermoscopy has added a new powerful dimension to the clinical diagnosis of early melanoma.
The qualities of a “good test” are accuracy, no adverse effects, target disorder dangerous if left untreated, and effective treatment if diagnosed early (Jaeschke et al., 1994). Dermoscopy has all of these attributes since the target disorder, melanoma, if diagnosed and removed early in its evolution, is curable.
8. Dermoscopy is a noninvasive technique that allows microscopic visualization of subsurface skin structures not visible to the naked eye.
Thus, the use of dermoscopy does not require additional expense to the patient for invasive procedures, such as the performance of biopsy, cost of processing the biopsy specimen, and interpreting the dermatopathologic diagnosis. Eliminating unneeded biopsies translates to overall reduced health care costs.
9. Adding dermoscopy to complete skin examinations is not overly time consuming.
Zalaudek et al. (2008) have shown that, on average, complete skin examination takes 70 seconds without dermoscopy and 142 seconds with dermoscopy. The authors conclude that complete skin examination, with or without dermoscopy, usually takes less than 3 minutes. They profess this is a reasonable time to potentially prevent mortality from cancers of the skin.
10. Meta-analysis of the literature has demonstrated the superiority and usefulness of dermoscopy.
Numerous studies (Vestergaard et al., 2008; Bafounta et al., 2001) have provided data to indicate that the diagnostic accuracy of dermoscopy is superior to that of naked-eye examination.
11. Dermoscopy allows the observer to focus (concentrate) on the lesion.
The procedure forces a pause during the busy total cutaneous clinical examination allowing time to think and formulate a logical differential diagnosis. Dermoscopy provides another chance to rethink the naked-eye examination conclusion allowing for a second opportunity to make the correct diagnosis.
12. Dermoscopy helps differentiate melanocytic from nonmelanocytic lesions.
This concept is explained in the “two-step” initial dermoscopic procedure, which differentiates melanocytic from nonmelanocytic lesions.
13. Dermoscopy increases the observers’ confidence in their clinical diagnoses.
It has been shown that, compared with naked eye examination of lesions of the skin, dermoscopy engenders greater degree of confidence in the correctness of the clinical diagnosis (Wang et al., 2008). The procedure also assures the patient that additional steps have been taken regarding the decision whether or not the lesion should be biopsied. When the confidence in a dermoscopic examination of a lesion reaches 100% that the lesion is benign, biopsy is almost always avoided.
14. Dermoscopy helps in the surveillance of patients with many melanocytic nevi.
In such patients certain lesions have attributes that do not meet the full criteria for melanoma but have some “suspicious” features. By using a comparative approach and short-term (i.e., every three months) sequential dermoscopic digital imaging, the lesions that appear similar to each other or remain unchanged or changed in a benign way can be followed (Altamura et al., 2008; Argenziano, 2011).
Credit: Dr. A.A. Marghoob