Successful treatment of chronic recurrent multifocal osteomyelitis with indomethacin: a preliminary report of five cases.

Chronic recurrent multifocal osteomyelitis (CRMO) is a disease of children and young adults. Clinically, the disease is characterized by the insidious onset of local pain and swelling in affected bones. Its course is one of intermittent periods of exacerbation and remission with successive bones affected. The pathogenesis of CRMO remains unknown, although an autoinflammatory disorder may be the cause, with inflammation of bone. This lesion is radiologically characterized as multiple lucencies surrounded by defined zones of patchy but dense sclerosis, cortical thickening from periosteal new bone formation, and increased bone size with different bones involved. Multiple therapeutic regimens had shown only a partial or temporary response. Because indomethacin has been successfully applied in inhibition of ossification and inflammatory processes, we initiated therapy with indomethacin in patients with CRMO. We report on the cases of 5 patients who responded dramatically to treatment with indomethacin. All underwent progressive clinical improvement (mean, 2.8 months). Radiological lesions disappeared after a mean period of 10.5 months. In 1 case where treatment was started late, small osteolytic zones persisted but with no clinical consequences. There were no additional recurrences or new bones affected during follow-up period (mean, 4 years). Our observation indicates that indomethacin may be an effective treatment for CRMO.