RESUMEN
BACKGROUND: The incidence of basal cell carcinoma (BCC) in younger individuals has increased in recent decades. However, the characteristics of BCCs in this population, especially in Ibero-Latin American countries, have not been completely defined. OBJECTIVE: To describe the demographic, clinical, and histopathological characteristics of BCCs in patients younger than 40 treated with Mohs Micrographic Surgery (MMS). MATERIALS AND METHODS: A multicenter, retrospective study conducted between January 2009 and December 2014, in five Ibero-American countries, included biopsy-proven BCCs in patients younger than 40 that were treated with MMS. Demographic, clinical, histopathological, and surgical characteristics were described. RESULTS: The study included 301 tumors in 241 patients, of whom 61% were female. The most common Fitzpatrick phototype was III. The most common histological subtypes were nodular (37.5%) and infiltrative (18.9%). Perineural invasion was encountered in 1.7%, and tumor clearance was achieved in 87.4% within two stages of MMS. CONCLUSIONS: This is the first Ibero-Latin American transnational study describing the characteristics of BCCs in young patients treated with MMS. Despite darker skin phototypes in this population, BCCs can occur in early ages and may present with aggressive features. Therefore, MMS may be considered an appropriate first-line treatment option in this population.