The term Histiocytosis X was characterized by the histiocytic appearance of the cells. Three disease variants were included in this description: eosinophilic granuloma, Letterer-Siwe disease and Hand-Schüller-Christian syndrome. In 1985, a Philadelphia workshop on childhood histiocytosis changed the generic name of this collection to Langerhans cell histiocytosis, in recognition of the main proliferative component of the cellular population.
We reported a case of eosinophilic granuloma of the mandible in a 9- year old girl, who was referred to the mandible unit with an intermittent swelling of the right cheek. The radiography revealed a poorly defined radiolucent area in the right mandible. The tumor was removed under general anaesthesia via an intra-oral incision. Immunohistochemically the tumor cells showed strongly S100 protein positive. The Birbeck granules were found in the cytoplasm by electronmicrscope. The histological and immunohistological features were indicative of eosinophilic granuloma.
