Diagnosis and conservative treatment of a rare case of femoral intraosseous arteriovenous malformation in a patient with polyostotic fibrous dysplasia: A case report.

Pure intraosseous arteriovenous malformation (AVM) in a limb bone is extremely rare. Furthermore, there is currently insufficient information on the diagnostic and therapeutic strategies for pure intraosseous AVMs. We herein report a case of pure intraosseous AVM of the proximal femur occurring in a patient with polyostotic fibrous dysplasia. The patient was a 39-year-old woman who presented with pain in the right thigh. Plain radiographs and computed tomography scans revealed a medullary lytic lesion with expansion and thinning of the bone cortex in the right proximal femur, mimicking a primary bone tumor. Magnetic resonance imaging (MRI) examination revealed intramedullary signal voids and feeding arteries arising from the deep femoral artery. A non-surgical approach using embolization and denosumab achieved satisfactory results, which included complete obliteration of the AVM, increased cortical thickness of the right proximal femur, and attenuation of the high-turnover bone metabolism 1 year later. Careful review of MRI images is crucial for distinguishing between bone tumors and intraosseous AVM, which exhibit signal voids and feeding arteries, in order to avoid unnecessary interventions such as bone biopsy or surgery.