Clinical-dermoscopic similarities between atypical nevi and early stage melanoma

Abstract

Atypical (Clark) nevi are benign tumors that may be considered precursors of melanoma. Many studies acknowledge a linear progression from typical to atypical nevi that eventually transform into melanoma. It is often challenging to differentiate a Clark nevus from melanoma, especially in its early stages, due to their clinical, dermoscopic, and histological resemblance. Dermoscopy is a powerful tool in early melanoma diagnosis, but it is a subjective method of examination. Therefore, the use of dermoscopic algorithms and checklists can overcome this issue. In the case of a difficult diagnosis, since both dermoscopy and histopathological exam are subjective methods of examination, modern molecular biology techniques can be used to distinguish between benign and malignant tumors. This study aimed to test the accuracy of specific clinical and dermoscopic criteria in order to distinguish between benign and malignant tumors, with a secondary objective to provide an overview of the clinical and dermoscopic features of atypical nevi and melanoma. In the present study, dermoscopic algorithms did not necessarily help distinguish benign and malignant tumors but demonstrated that nevi and melanoma have similar characteristics.

Keywords: atypical nevi; dermoscopy; early diagnosis; histology; melanoma.

Figure 1

‘ABCDE rule’ criteria in atypical nevi and melanoma.

Figure 2

‘Chaos and clues’ in atypical nevi and melanoma. (A) Atypical nevus with thick lines (white arrow) and grey-blue structures (blue arrow). (B) Atypical nevus with polymorphous vessels (white circles). (C) Atypical nevus with eccentrical structure (white circle). (D) Atypical nevus with peripheral black dots. (E) Atypical nevus with pseudopods. (F) Melanoma has chaos, eccentrical black structure (white arrowhead), white lines (black arrowhead), and grey structures (white circle).

Figure 3

‘Chaos and clues’ algorithm in atypical nevi and melanoma.