Tumours derived from Langerhans cells (LCs) are divided into two main subgroups, according to the degree of cytological atypia and clinical aggressiveness: LC histiocytosis (LCH) and LC sarcoma. Both subgroups maintain the phenotypic profile and ultrastructural features of LCs. LCH is a clonal neoplastic proliferation of Langerhans-type cells that express CD1a, langerin, and S100 protein, showing Birbeck granules by ultrastructural examination. Here the clinicopathological of LCH will be discussed.