Lentigo Maligna: Keys to Dermoscopic Diagnosis.

Dermoscopy is a noninvasive technique that improves accuracy in the diagnosis of cutaneous lesions. The recognition and differential diagnosis of lentigo maligna (LM) and lentigo maligna melanoma (LMM) is challenging, especially in the early stages when there are no distinctive clinical features. Early diagnosis and appropriate treatment can improve prognosis. Several dermoscopic features have been described for LM and LMM. The following 4 criteria in combination have achieved a diagnostic sensitivity of 89% and a specificity of 96%: asymmetric pigmented follicular openings, dark rhomboidal structures, slate gray dots, and slate gray globules. A biopsy is warranted when dermoscopic examination reveals a grayish coloring. For a flat pigmented lesion acquired in adulthood, a histopathological diagnosis of "atypical junctional nevus" is not to be accepted uncritically. LM and LMM can also appear in sites other than the face, and dermoscopy can facilitate their recognition. Dermoscopy is an essential tool for physical examination.