chronic recurrent multifocal osteomyelitis; manifestation, imaging and diagnosis

chronic recurrent multifocal osteomyelitis (crmo) is an inflammatory bone disease usually affecting children. a 9-year old boy presented with recurrent lower extremities pain and discomfort lasting for two years. in every time, symptoms vanished after several weeks. the patient received antibiotics only in one period of bone pain. in other occasions the patient didn’t received any antibiotics. in last episode of bone pain, symptoms disappeared by use of naproxen. in patient’s x-rays, there were multifocal areas of sclerosis with a wide transitional zone accompanied by a fine periosteal reaction. regarding his history and mri, bone scan findings were more in favor of active inflammatory process in the involved regions. in needle biopsy and bone curetting of left & right tibiae, osteonecrosis, mild inflammatory fibrosis, and scattered chronic inflammatory cells consistent with chronic osteomyelitis were noticed. no malignant neoplastic tissue was identified. in 2-year follow-up, diagnosis of crmo was confirmed by serial laboratory tests, three-phase bone scan, ct and mri findings. this diagnosis was proved by pathology evaluation following needle bone biopsy.