By Allison Evans, staff editor, March 1, 2012
Dermatologists have an array of methodologies used to diagnose and treat patients, including scrupulous skin examinations and diagnostic tools that aid in assessing, confirming, and — in some cases — reconsidering diagnoses. With many dermatologists’ medical evaluations relying on observations made by the naked eye, diagnostic tools can make a real difference and assist with creating a proper treatment plan for patients.
Dermoscopy gains ground
One diagnostic tool that’s gaining popularity is dermoscopy, which, according to the Journal of the American Academy of Dermatology, is a specialized technique in which a dermatoscope is used to view subsurface anatomic structures of the epidermis and papillary dermis unobstructed by light reflection, refraction, and diffraction (2003;49:777-97).
While dermoscopy isn’t new — it’s been used since the late 1800s — the technique didn’t become widely used until the 1980s, when case studies emerged showing an increase in diagnostic accuracy of melanoma along with the wide availability of portable, handheld dermatoscopes, said Jason B. Lee, MD, associate professor of dermatology and cutaneous biology at Thomas Jefferson University Hospital, Philadelphia. “Currently, in Europe and Asia the use of a dermatoscope is the standard of care in evaluating pigmented lesions,” he said. Dr. Lee will be presenting on clinical dermatoscopic pathologic correlations at the Academy’s 70th Annual Meeting this month in San Diego.
Dr. Lee, a proponent of advancing dermoscopy research, has been practicing dermoscopy for the past decade. He uses a dermatoscope on almost every patient, whether the patient has an inflammatory or neoplastic skin disease. “The information obtained from a dermatoscope provides additional morphologic evaluation of skin lesions,” he said. This additional information can help inform a doctor’s diagnosis.
While dermoscopy is primarily used as a tool to help detect early melanomas, it can also be used to help diagnose skin tumors, scabies, warts, fungal infections, and diseases of the hair and scalp.[pagebreak]
More research necessary
Dr. Lee, who noted a definite lack of well-designed, randomized prospective studies on dermoscopy, found he was better able to diagnose pigmented lesions through dermoscopy, especially non-melanocytic lesions that simulate melanoma. This resulted in a decrease in the number of biopsies he performed. “Even if the lesion was biopsied eventually, I was able to convey to the patients my diagnostic impression with more confidence and precision,” he said.
Dr. Lee is part of a research group that is currently designing a study to determine the impact of dermoscopy on patient management. “The expert dermatoscopists have established that the use of a dermatoscope increases the diagnostic sensitivity and specificity of melanomas. Whether these advantages can be replicated in the community settings has not been demonstrated,” he noted.
TBP: Getting the whole picture
Another diagnostic tool gaining wider use by dermatologists is total body photography (TBP) or “mole mapping,” which documents an individual’s entire skin surface through a series of body sector images. This system is particularly helpful when used with patients who have a personal or family history of melanoma. As higher-risk patients continue to have nevi examined, total body images help record worrisome spots and delineate changes or new spots that may compel dermatologists to take further action.
Opinions differ, however, about the efficacy of TBP.
“The thing about [TBP] is that everyone says that you have to do it and that it helps you find melanomas. But we need scientific evidence that it improves survival of patients with melanomas,” said Gary Goldenberg, MD, assistant professor of dermatology and pathology at Mount Sinai Medical Center in New York.
While Dr. Goldenberg doesn’t advocate using TBP on most or all patients, he does recognize its value. For the “right” patient — one that is at high risk for melanoma — TBP can be a useful way to record and monitor atypical nevi, Dr. Goldenberg said.
If the efficacy of TBP is still undetermined, a study in Melanoma Research (2010;20(5):417-21) has shown that dermatologists who do use it find that it reduces patient anxiety, leads to fewer biopsies, and can help detect early-stage melanoma.
Most dermatologists believe TBP is useful in the follow-up management of pigmented lesions because it allows dermatologists to gauge new or changed lesions. To document isolated lesions, a 35-mm or, more likely, a digital camera can be used. For total-cutaneous photography, there are other considerations, such as other photographic equipment like lights and camera stage as well as patients’ poses, and the system used to store and review images. All of these considerations come into play when deciding which type of photography is most beneficial (J Am Acad Dermatol 2003;49:777-97).
TBP can also help patients monitor their own skin, as they can walk away with prints as a benchmark for future self-examinations.
Getting under the skin
In addition to TBP and dermoscopy, reflectance confocal microscopy (RCM) is another tool used by dermatologists when making the decision to biopsy. Unlike dermoscopy, with RCM the light penetrates beneath the skin’s surface, giving dermatologists yet another way to examine skin lesions. “The confocal microscope is a noninvasive technique that allows for the horizontal plane visualization of microscopic structures and cellular detail of the epidermis, dermo-epidermal junction, and the superficial dermis,” said Harold Rabinovitz, MD, a dermatologist in Plantation, Fla., whose practice uses both dermoscopy and confocal microscopy to help evaluate benign and malignant neoplasms of the skin.
RCM provides better optical resolution than wide-field microscopes because of point illumination, which prevents out-of-focus glare from decreasing the image’s resolution.
“With the eye, our sensitivity is good. With the dermatoscope, it’s even better. And with the confocal microscope, it’s the best of all,” Dr. Rabinovitz said. “This is because you’re looking at images at the cellular level.”
The confocal microscope works when a light source illuminates a small spot within the tissue, said Dr. Rabinovitz. “The light is then reflected from the tissue through a pinhole. We see a very small area of about 0.5 mm of the area that we’re visualizing. The instrument automatically moves over the entire plane so that you can scan as much as an 8-by-8-mm area by stitching the blocks into a mosaic,” he said. While it can be a time-consuming examination, studies show that RCM may improve diagnostic specificity of melanocytic lesions, especially when applied on difficult cases (J Am Acad Dermatol 2005;53(6):979-85).
According to the same article published in the Journal of the American Academy of Dermatology, a potential drawback to RCM is that the light source limits the depth of penetration to about 200 to 300 µm, allowing deeper lesions to go undetected.
“[RCM] is a wonderful tool for identifying basal cell carcinomas, squamous cell carcinoma, and early melanomas on sun-damaged skin…. Not all melanomas are the same. Melanomas on sun-damaged skin, particularly on the face, can often look like a lentigo, and there are clear features that help us distinguish between melanomas on sun-damaged skin and solar lentigines,” Dr. Rabinovitz said.
An article published in the Journal of Investigative Dermatology (2009;129(1):131-8) showed that the combination of clinical, dermoscopy, and confocal microscopy had a higher diagnostic accuracy than each individually and that the techniques are complimentary, Dr. Rabinovitz said.
Training is a must
It’s essential that dermatologists complete the necessary training before using any diagnostic tool. Some of this is covered in the standard training done in residency, while other devices require more specialized training. “Dermoscopy, for example, requires formal training; one study, published in the Journal of the American Academy of Dermatology (1997;36:197-202), recommended nine hours of training. Without training, diagnostic accuracy may be worse than a naked-eye examination alone,” Dr. Lee said.
At the Academy’s 70th Annual Meeting in San Diego, dermoscopy courses will abound, with everything from Basic Dermoscopy (W002) and Dermoscopy for the Non-Dermoscopist (U077) to Advanced Dermoscopy (C031) and Hair and Scalp Dermoscopy (F036).
To view the Academy’s entire listing of dermoscopy courses at the Annual Meeting, search “dermoscopy” in the online searchable program book at www.aad.org/scientificsessions/am2012.
The AAD also offers “Dermoscopy: A Guide for the Physician,” with more than 8,000 images and 400 cases in a two-disc DVD set for sale. It was created by world-renowned experts in the field of dermoscopy, under the direction of Dr. Rabinovitz. The guide is available online at www.aad.org/store or by contacting the Academy’s Member Resource Center.
While the initial training on any device is critical to getting accurate results, it’s also important to continue training, especially since devices change and improve over time. “Dermoscopy and confocal microscopy both have a learning curve, so courses are certainly beneficial,” Dr. Rabinovitz said. He also reminded that with rapid advances in technology, training may differ from what was first learned in residency.[pagebreak]
Dr. Goldenberg also emphasized that as critical as diagnostic tools can be in helping treat patients, they’re not a crutch or replacement for reason and judgment. “These are tools,” he stressed. “They do not replace well-trained, experienced dermatologists who take their time looking at patients’ spots,” he said.
Dermatologists are still the best diagnostic “tool.”
“These diagnostic devices bridge the clinical with the histologic and allow us to see structures not visible to the naked eye,” Dr. Rabinovitz said.
But while dermatologists benefit from having a wide variety of diagnostic tools at their disposal, there is no one magic diagnostic tool that provides a pat answer. Ultimately, biopsies are still the gold standard for diagnosis, Dr. Goldenberg said. “All these tools are helpful, but nothing replaces a set of good eyes of a clinician and a dermatopathologist,” he said. Many diagnostic tools are detecting melanoma earlier, but more studies are needed to determine whether or not they affect survival rates, Dr. Goldenberg said.
“The diagnosis of pigmented lesions is based not only on morphologic findings alone, but also on palpation, history, and context, any of which may play a more important role depending on the clinical situation,” Dr. Lee said.
Diagnostic tools are only one piece of the puzzle; the dermatologist’s job is to study these pieces and fit them together in the best way possible.
Dr. Rabinovitz agreed. “All of these devices require judgment on the part of the physician. The decision-making process is often complex, and experience will play an integral part in deciding which tool is best utilized.”