Contributor: Gordon K. Klintworth
The term eosinophilic granuloma has unfortunately been used to desigate several distincly different entities. It is mainly used for a component of Langerhans cell histiocytosis, but is also used as a synonym for Kimura disease. The Langerhans cell histiocytosis form of eosinophilic granuloma is a benign osseous tumor of childhood and young adults, but is rarely encountered after 30 years of age. Almost any bone can be affected. About 50% of cases occur during the first decade of life. The lesions may be solitary or multiple. Radiologically the lesions are lytic and can be confused with Ewing sarcoma. Microscopically the lesion consists of Langerhans cells accompanied by numerous eosinophils and foci of chronic inflammatory cells may be present. The hisiocytes are positive for S-100 and peanut agglutinin. Treatment is an intralesional injection of steroids, curettage or radiotherapy. It is part of the clinical spectrum of Langerhans cell histiocytosis (Histiocytosis X). It is a neoplastic proliferation of Langerhans cells. Other presentations are Letterer-Siwe disease (a fatal disease of childhhood) and Hand-Schüller-Christian disease (a chronic disease of adults with diabetes insipidus,calvarian bone defects and exophthalmos). The pituitary gland may be involved in all three syndromes, but especially in Hand-Schüller-Christian disease. Infiltrates of histiocytes and Langerhans cells are present in the bone, orbit, posterior pituitary gland, infundibulum and infundibular stem.