Navarrete‐Dechent, Cristián

Abstract Lentigo maligna (LM) is a subtype of cutaneous melanoma in situ that develops on chronically sun‐damaged skin in elderly individuals. Its diagnosis and management remain challenging due to its slow progression, frequent occurrence on cosmetically sensitive areas in frail individuals, and tendency for subclinical peripheral extension. Despite its potential for invasive transformation, the natural history of LM remains incompletely understood and evidence‐based management strategies for this specific entity remain limited. This work aims to bridge the gap between scarce high‐quality evidence and the clinicians' need for practical guidance on LM management by formulating evidence‐based and expert consensus‐driven recommendations for diagnosis, treatment and follow‐up. Under the coordination of the International Dermoscopy Society, a global, multidisciplinary consortium of 53 experts—including dermatologists, dermato‐oncologists, dermatologic surgeons, radiologists, radiotherapists, pathologists and epidemiologists—formulated recommendations through structured consensus, informed by a comprehensive review of current scientific evidence and clinical practice standards. Optimal management of LM requires accurate diagnosis and individualized treatment planning. Non‐invasive skin imaging techniques, especially dermoscopy and reflectance confocal microscopy, aid in diagnosis, biopsy orientation, lesion delineation and post‐treatment monitoring. Multiple partial biopsies help confirm diagnosis and rule out invasion. Complete surgical excision remains the first treatment option. No definitive safety margins can be recommended for standard surgery; margin‐controlled techniques are preferable for large or ill‐defined lesions. Topical imiquimod and radiotherapy are effective alternatives where surgery is unsuitable. Topical imiquimod is useful as primary, adjuvant or neoadjuvant therapy. Blind destructive methods should be avoided. Close clinical and imaging follow‐up is needed. Patient‐centred care, shared decision‐making, and a multidisciplinary approach are critical for optimal outcomes. These international consensus recommendations summarize current best practices for LM management, offering practical, evidence‐informed guidance to clinicians while acknowledging the potential of future research in refining these conclusions.

Introduction: Porokeratosis is a group of keratinization disorders characterized by the histopathological presence of the cornoid lamella, a hallmark feature across all subtypes. The clinical diagnosis of porokeratosis can be challenging due to its similarity to other dermatological conditions. While polarized light dermatoscopy (PLD) enhances diagnostic accuracy, certain features remain difficult to identify. Ultraviolet-induced fluorescence dermatoscopy (UVFD) is a novel imaging technique that may improve the visualization of porokeratosis features, particularly the peripheral keratin rim. Objectives: This study aimed to assess the diagnostic utility of UVFD compared with PLD in identifying the dermatoscopic features of porokeratosis. Methods: In this retrospective study, dermatologists from five institutions in Chile, Brazil, Poland, and the United States contributed with dermatoscopic images of porokeratosis cases. Both PLD and UVFD images were obtained for each lesion. Two independent investigators evaluated each lesion in PLD and UVFD for the presence of peripheral keratin rim, rim continuity, central scaling, follicular plugs, vascular structures, and photodamaged surrounding skin. A third investigator reviewed discrepancies. Frequencies and means were calculated. McNemar’s chi-square was used for comparison. Results: A total of 136 lesions from 35 patients with biopsy-proven porokeratosis were analyzed. UVFD significantly improved the visualization of the peripheral keratin rim (95.6% vs. 66.2% in PLD; P<0.001) and increased identification rates for central scaling, follicular plugs, and interrupted rims. PLD remained superior for detecting vascular structures(P<0.001). Conclusions: UVFD enhances the visualization of key dermatoscopic features of porokeratosis, particularly the peripheral keratin rim and other keratin-related structures.