Dermoscopic Features and Algorithm- A Guide to Detecting Pre-Malignant Facial Pigmented Skin Lesions in Ethnic Skin

Abstract

Introduction: Detection of pre malignant facial pigmented lesions on a photo damaged ethnic skin has been crucial for dermatologists in preventing malignant transformation. Facial Pigmented Skin Lesions (FPSLs) that render a diagnostic challenge include, Pigmented Actinic Keratosis (PAK), early Seborrheic Keratosis (SK), Solar Lentigo (SL) and Lentigo Maligna (LM). Dermatoscopy or epiluminescence microscopy, is skin surface microscopy that has demonstrated to be a non-invasive, in vivo, high yield technique to evaluate a pigmented macule for an atypical evolution. Objective: To establish dermatoscopic findings of clinically challenging FPSLs conforming PAK, SK, SL and LM and derive an Algorithm with diagnostic features for detecting Premalignant Facial Pigmented Skin Lesions. Subjects and Methods: We here in conducted a largest case study a cross-sectional analysis of clinically challenging 182 flat FPSLs, evaluated dermoscopic images consistent to pigmented AK, early SK, SL and LM and subsequently biopsied for histopathological evidence. Four major dermoscopic features were appraised: pigment pattern, sharp demarcation, vascular criteria and follicular/epidermal pattern. Study Design: Cross sectional validation-study Setting: Department of Dermatology Unit II, King Edward Medical University, Mayo Hospital Lahore. Study was conducted for a period of six months. Result: We derived an “Algorithm” elucidating diagnostic findings of FPSLs. Pigmented AK on dermoscopy has strawberry pattern in 42% of lesions (pink to red pseudo-network with erythematous background, prominent follicular ostia fenced by a white targetoid halo), while Sharp demarcation (57.15%) and follicular/epidermal pattern (cerebriform pattern 100% of lesions, milia-like cysts, 50%, and comedo-like openings 38.57%) are distinctively observed SK. In SL, homogenous structureless pigmentation is significant entirely (100%). However, in LM predominates pseudonetwork (89.47%), homogenous structureless pigmentation (78%) and vascular patterns while strawberry pattern is observed in (26.31%) of lesions. Conclusion Our “Dermoscopic Algorithm” constitutes diagnostic characteristics of “Facial Pigmented Skin Lesions,” that would not only aid in early corrective detection of clinically similar lesions with different biologic behavior, but serve the the purpose to prevent vigorous malignant transformation in photo damaged ethnic skin, particularly Lentigo Maligna turning into a potential Melanoma, Hence, Sharp demarcation with cribriform pattern is specific of Sebhorric Keratosis (SK), while homogenous structureless pigmentation without prominent vascular pattern is distinctive of Solar Lentigo (SL). Pigmented Actinic Keratosis (AK) is described by prominent strawberry pattern. Nonetheless, homogenous structureless pigmentation and vascular pattern with pseudonetwork are featured in Lentigo Maligna (LM), lacking of prominent strawberry pattern. Conflict of Interest: The Authors have no conflict of interest to disclose.