Dermoscopy of facial flat pigmented lesions: a series of 406 cases

Objective: The diagnosis of facial pigmented lesions remains challenging due to overlapping clinical and dermoscopic features, particularly in individuals with darker phototypes. This study aimed to evaluate and compare the dermoscopic characteristics of common facial pigmented lesions and assess their diagnostic relevance. Methods: A retrospective and prospective observational study involving 406 lesions from 274 patients was analyzed through a descriptive and analytical approach, with diagnoses based on clinical and dermoscopic criteria and confirmed by histopathology. Results: Solar lentigo (n = 170) was significantly associated with dermoscopic lightening, sharp borders, homogeneous brown pigmentation, moth-eaten borders, and symmetrical perifollicular pigmentation. Seborrheic keratosis (n = 83) showed strong associations with sharp borders, fingerprint patterns, fissures and ridges, pseudocomedones, and cerebriform structures. Lichenoid keratosis (n = 60) was predominantly characterized by a diffuse granular pattern. Pigmented actinic keratosis (n = 82) was mainly associated with a pigmented pseudonetwork, rhomboidal structures, gray halos, and annular granular patterns. Lentigo maligna (n = 11) demonstrated significant associations with asymmetrical pigmented follicular openings, target-like structures, and rhomboidal patterns. Conclusion: Overall, dermoscopic features showed considerable overlap among lesions and variability according to phototype, emphasizing the importance of a phototype-oriented dermoscopic approach to improve diagnostic accuracy.