Poster Presentation ASPCR-ASDR Conference 2013

Actinic lentigines: hyperpigmentation associated with profound alterations of cutaneous architecture. (#115)

Christine Duval 1 , Stéphanie Nouveau 1 , Muriel Monot 1 , Philippe Bastien 1 , Emilie Warrick 1 , Corinne Chagnoleau 1 , Jean-Paul Ortonne 2 , Olivier de Lacharrière 1 , Francoise Bernerd 1
  1. L'OREAL R&I, CLICHY, France
  2. Dermatology Department - Hôpital l'Archet , Nice, France

Actinic lentigines (AL) are benign skin hyperpigmented lesions frequently found on sun-exposed sites in elderly people. However their histopathological features remain ill-defined. This study aimed at better describing morphological and biological features of AL expressing a similar clinical phenotype i.e. an elongated honeycomb pattern detected by epiluminescence and quantified through image analysis. Two biopsies were obtained from AL lesion and adjacent non lesional (NL) skin on the dorsal side of hands of 15 Caucasian women. In all lesions, HES staining revealed a drastic elongation of the dermal-epidermal junction associated with epidermal invaginations within the dermis. Morphometric analysis revealed a significant increase in the basal layer length and a higher undulation index in AL. The melanin content was found statistically higher and preferentially located within the epidermal basal layer in AL as compared to NL. However, melanocytes were found evenly distributed along the basement membrane, in both AL and NL, and the number of melanocytes per length of basal layer was similar. Furthermore, MITF and tyrosinase immunostainings showed that melanogenesis activity was not increased in AL. These findings indicate that both the higher melanin content and the disorganization of epidermal, dermal and junctional cutaneous structures should be taken into account in the follow-up of long-term treatments for age spots.