[Melorheostosis in adults. Apropos of 2 cases, 1 of them treated with diphosphonate (EHDP)].

The authors report two cases of melorheostosis discovered in adults because of fairly intense pain and deformation of the affected limb. The radiological appearances were typical. Isotope bone scintigraphy showed strong hyperfixation in the affected bones. A histomorphometric study of a double iliac bone biopsy showed on the one hand, cortical hypertrophy, normal osteonic architecture, and normal lamellar texture in the pathological regions, and, on the other hand, the dynamic character of the healthy bone close the lesions. In one of the patients an original attempt at treatment with diphosphonate (1 200 mg/day of EHDP for 5 months) resulted in a clear improvement in the bone pain. The disease is considered to be a mesodermic dystrophy. It seems to be due to strong hyperactivity of the subperiosteal bone accretion, which, normally, persists only at a weak level in adults.