Detecting melanoma: Digital dermoscopy, total body photography help diagnose dysplastic nevi

July 1, 2008

Diagnostics techniques such as dermoscopy, total body photography and digital dermoscopy can assist the dermatologist in diagnosing troublesome nevi and catching early melanomas more frequently.

Key Points

Barcelona, Spain - In addition to dermoscopy, total body photography and digital dermoscopy can significantly assist the clinician in differentiating benign lesions from malignant lesions. According to one expert, these diagnostic techniques should be an integral part of skin lesion examinations.

Any patient can have dysplastic or atypical nevi; however, these lesions become "problematic" in patients with multiple nevi or dsyplastic nevus syndrome, sometimes posing a difficult dermatological challenge.

"But most of the time, these lesions are benign and serve as risk markers," says Joseph Malvehy, M.D., coordinator of the melanoma unit, department of dermatology, Hospital Clinic IDIBAPS, Barcelona, Spain.

Rules of diagnosis

According to Dr. Malvehy, this is the reason different rules of diagnosing skin lesions have been introduced, such as the ABCDE rule. The addition of the letter "E" to the acronym is to indicate enlargement or evolution.

"This means that a given skin lesion is undergoing a perpetual metamorphosis, and if it is melanocytic - and especially if it is atypical - it should be removed," Dr. Malvehy tells Dermatology Times.

Dr. Malvehy says even in this case, however, the ABCDE method is still very low in specificity. This is why dermatologists need to remove a lot of benign lesions to find one melanoma.

According to Dr. Malvehy, the ratio is approximately one melanoma for every 14 benign lesions.

"This is why dermoscopy was introduced, and this diagnostic tool has significantly helped us in the recognition of malignant lesions, improving the ratio to one melanoma for every four benign lesions. This is a tremendous advance in the recognition of early melanoma and in the saving of unnecessary biopsies in our patients," Dr. Malvehy says.

Photography, digital dermoscopy

"When using these imaging techniques (total body photography and digital dermoscopy), we are able to detect new lesions in our patients as well as very subtle changes in early melanomas in our patients with atypical mole syndrome.

"These methods are used in different units and cancer centers in different continents, and various publications support the importance of these new strategies in the diagnosis of melanoma in these patients," Dr. Malvehy says.

Dr.Malvehy says pathologists do not readily agree on the interpretation and diagnosis of in situ melanoma and atypical lesions.

At times, the definitive diagnosis of dysplastic nevus is a tricky one, as it is up to the pathologist and his or her histopathologic interpretation of the histologic material.

However, all specialists agree that any potential malignant lesion, whether early melanoma or lesions that are atypical, should be detected as early as possible and, most of the time, should be removed.

In addition to total body photography and digital dermoscopy, there is an evolving and exciting technology for the noninvasive in vivo skin examination of tumors, namely confocal microscopy, Dr. Malvehy says.

"Our experience with confocal microscopy is becoming very positive. Furthermore, the combination of confocal microscopy and dermoscopy is now possible. We are finding that in suspicious lesions or in lesions located on the face where a biopsy may not be aesthetically ideal and should be very well-selected, confocal microscopy is giving us a very good opportunity to improve our diagnostic capabilities and, therefore, the better management of our patients," Dr. Malvehy says.