Lentigo maligna (LM) and lentigo maligna melanoma (LMM) are slow growing tumors located on the face, that may be very difficult to distinguish from common benign lesions with naked eye. In 2000, Stolz et al published a seminal article determining four dermatoscopic features (asymmetric pigmented follicular openings, dark rhomboidal structures, slate-gray dots, and slate-grey globules) that could detect lentigo maligna (LM) with high accuracy. According to the results observed, a progression model of LM was developed and has been taught since then. After 20 years, we would like to update this model to reflect the current cases we are seeing on our daily practice. Therefore, we conducted a retrospective study of 153 histologically proven lentigo maligna diagnosed between January 2011 and March 2023, from two tertiary referral centers (Melanoma Unit of Hospital Clinic, Barcelona, Spain and Hospital 12 de Octubre, Madrid, Spain). A total of 153 patients were included, 86 (56.2%) men and 67 (43.8%) women, mean age 72 years (range 31-97). Overall, there were 112 (73.2%) LM and 41 (26.8%) LMM. Among all LMM, median and mean Breslow thickness was 0.7mm and 2.1mm, respectively (range 0.2-25mm). Of note, female patients presented mean Breslow thickness of 0.75mm compared to 3.02mm of male counterpart (p logBreslow = 0.013). Men had significant more affected the ear (p=0.004) and the scalp (p=0.005) than women. The most common dermoscopic findings were pseudonetwork irregularly distributed (129; 84.3%) and dots (119; 77.8%). Among Stolz criteria, hyperpigmented follicular opening was the most frequent feature (103; 67.3%), followed by short streaks (91; 59.5%), pigmented rhomboidal structures (72; 47.1%), annular-granular pattern (54; 35.3%) and obliterated hair follicles (43; 28.1%). In conclusion, our cohort of 153 LM/LMM cases revealed that the most frequently dermoscopy features were pseudonetwork and dots, which are not specific malignant criteria. Being aware of this challenge is crucial to avoid mistreatment and late diagnosis that can lead to patient morbidity and radical surgical treatments.
New insight in Dermoscopy of LM/LMM.
Mitsunaga, K. (Author). 2023
Student thesis