[Erdheim-Chester disease: report of a case, review of the literature and discussion of the relation to Langerhans-cell histiocytosis].

Erdheim-Chester disease is an endogenous, non-genetically-determined lipidosis characterized by infiltrates of foamy, lipid-laden histiocytes and by bilateral symmetric foci of sclerosis in appendicular long bones. The clinical spectrum ranges from focal bone lesions to systemic disease with life-threatening visceral involvement. In one third of patients, roentgenograms show focal osteolysis within areas of sclerosis. Authors report a new case of Erdheim-Chester disease documented by two bone biopsies in different sites. Features in their patient included: 1) osteolysis and sclerosis of the long bones of the limbs and maxillas, with CT scan evidence of cortical rupture; 2) on magnetic resonance imaging studies, heterogeneous foci of decreased signal intensity on T1 images and heterogeneous areas of moderately increased signal intensity on T2-weighted images; 3) increased serum osteocalcin levels; 4) laboratory evidence of chronic inflammation with no extraosseous manifestations. The clinical, radiological, and pathological features of Erdheim-Chester disease are different from those of Langerhans cell histiocytosis. However, three cases of patients with both conditions have been reported in the literature, suggesting that there may be links between the two diseases.