Idiopathic periosteal hyperostosis with dysproteinemia. A new clinical entity.

Two unrelated children, suffering from a transient illness characterized by fever, bone pain and tenderness, inability to walk, x-ray evidence of subperiosteal new bone formation and dysproteinemia, are described. In both children the onset followed a respiratory infection. The fever lasted for about three weeks in 1 patient and two months in the other. As fever subsided, the x-ray evidence of periosteal hyperostosis gradually disappeared, and the electrophoretic pattern of the serum proteins returned to normal. Tibial biopsy in 1 patient showed subperiosteal new bone formation of the right-angled type, with no inflammation and with the presence of mucinous edema. Plasma cells were unusually abundant in the bone marrow. The serum protein disturbance was characterized by hypoalbuminemia and striking elevation of the alpha2 and gamma globulins. Detailed serum protein studies performed in 1 patient showed the hypergammaglobulinemia to be due primarily to an increase in the IgG fraction. No etiologic agent was identified, and recovery was complete in both patients. The entity does not appear to have been described previously.