Recent studies have highlighted the rising incidence of melanoma in non-white skin. In populations with darker complexions, melanomas may appear on areas of the skin not exposed to the sun, often of the acral lentiginous type.
The stage at diagnosis is also more advanced in non-white skin. Despite increased surveillance efforts, diagnosis of melanoma in darker skin is often difficult and delayed, which affects overall prognosis and likelihood of survival. When stratified by stage of diagnosis, melanoma in non-white skin has the same prognosis as melanoma in white skin.
Pigmented skin lesions are rarely noticed and are difficult to detect by clinical examination on dark skin because of reduced visibility of melanocytic lesions.
Using a dermatoscope to examine dark skin for melanomas could help improve the chance of correct diagnosis and earlier treatment if done properly. The use of dermoscopy is increasing in favor among dermatologists to improve diagnostic accuracy.
Few studies have reviewed the use of dermoscopy in darker skinned populations. In one study investigators evaluated the utility and efficacy of dermoscopy for pigmented lesions in black populations. The authors attempted to evaluate whether darker pigmentation influences dermatoscopic features in comparison with white populations (Brit. J. Dermatol. 2006:4;695-99).
In the study, 100 clinically doubtful or equivocal pigmented skin lesions in black patients were subjected to dermatoscopic examination. The lesions were observed using dermoscopy by two groups of dermatologists, one in Brazil (in vivo) and the other blinded evaluators in Italy (on slide images), both recording dermatoscopic features. The results showed that out of 100 cases, 79 were Clark nevi, 15 seborrheic keratoses, 4 blue nevi, 1 dermatofibroma, and 1 melanoma.
The agreement between observers was statistically evaluated and there was a high level of inter-observer agreement among dermatoscopic features. Only 3 out of the 100 suspicious lesions (Clarkâs nevi) required surgical excision to confirm the diagnosis.
The melanomas presented dermatoscopic characteristics similar to the melanomas appearing in white populations with a blue-whitish veil, irregular globules and streaks at the periphery.
The increased incidence of melanoma, and decreased survival of ethnic patients due to a delay in diagnosis, is a sign of caution to dermatologists to increase surveillance of pigmented lesions in dark skin. Accurate classification of pigmented lesions is difficult; however, this study showed that dermoscopy can be a useful and even necessary tool in the identification of pigmented lesions in dark skin, as naked-eye examinations may be more difficult.
More accurate diagnoses can lead to, not only earlier treatment of clinically suspicious lesions, but also to a decrease in unnecessary biopsies in skin of color, which is more prone to hypertrophic and keloidal scarring.