[Langerhans cell histiocytosis: Letterer-Siwe disease - the importance of dermatological diagnosis in two cases].

Langerhans cell histiocytosis is defined as a clonal proliferation of Langerhans phenotypic-like cells. Letterer-Siwe disease is the most common and serious of these entities, affecting mainly infants up to two years of age. We present two cases of this rare disease, diagnosed after dermatological examination, highlighting its typical aspects.