This article reports a case of oral mucosa lesions as the sole manifestation in Langerhans cell histiocytosis (LCH). This is a very uncommon manifestation of LCH since this disease preferably affects the bones with frequent involvement of the jaws. LCH may also involve other organs, particularly the lungs, liver, lymph nodes, and skin. The highlights of this report are the differential diagnosis, immunohistochemical analysis and, mostly, the therapeutic approach.