ECTOPIC HEMATOPOIETIC BONE-MARROW IN THE APPENDICULAR SKELETON AFTER TRAUMA

Methods: Combined bone scanning and immunoscintigraphy (IS) with Tc-99 m-monoclonal antigranulocyte antibodies were performed in two patients with suspected reactivation of chronic osteomyelitis of the lower ext remity. Because bone scanning and IS were strongly positive, both pati ents underwent surgical intervention. Results: Macroscopic findings di d not show purulent infection and microbiologic results remained negat ive, but histology revealed unexpected ectopic bone marrow, explaining the strong uptake on IS. One patient exhibited active hematopoietic b one marrow at the former fracture site of the tibial bone. The second patient presented with interspersed bone marrow in the cortical bone o f the femoral diaphysis after several intramedullary surgical procedur es. Conclusion: Unexpected ectopic hematopoietic marrow may occur in t he appendicular skeleton after trauma and repeated surgical interventi ons. The bone marrow shows a physiologic uptake with IS and may be mis interpreted as granulocyte accumulation due to infection. This may lea d to false-positive diagnosis in cases of suspected osteomyelitis.