Hand-Schüller-Christian disease.

Langerhan cell histiocytosis, formerly known as histiocytosis X, traditionally denotes a group of diseases that stem from proliferative reticuloendothelial disturbances.The etiology and pathogenesis of the disease remain debatable. In this paper we report a case of Langerhan cell histiocytosis in a 3 1/2 -year-old child who reported to the department of oral pathology with gingival enlargements.