Dermoscopy for "true" amelanotic melanoma: a clinical dermoscopic-pathologic case study

Abstract

Completely amelanotic melanomas are rare and therefore often misclassified, with tragic consequences for patients. The use of dermoscopy for these lesions has not been validated yet because of the lack of studies that are based on large series. The analysis of the vascular pattern, which is often the only dermoscopic parameter to be seen, is therefore essential for a correct diagnosis. We present a case of "true" amelanotic melanoma on the forehead of an 89-year-old man, which clinically mimicked squamous cell carcinoma. The patient was investigated both clinically and by focusing on his dermoscopic features and their pathologic correlates. The dermoscopic diagnostic algorithms routinely used for pigmented lesions are not helpful in diagnosing amelanotic melanoma because they are based on specific parameters not normally seen in amelanotic lesions. In the light of our experience, pattern analysis is the most reliable method for diagnosing these particular lesions correctly because it allows in-depth morphologic analysis of the few parameters found.