Eruption of a venous malformation through an iliac bone harvesting site after trauma

Harvesting grafts from the anterior iliac bone has been associated with various complications. A 50-year-old woman presented to our department with a chief complaint of right inguinal swelling and pain. Autologous bone grafts had been harvested on two previous occasions from the right anterior iliac crest for use in the reconstruction of multiple facial fractures. Computed tomography and magnetic resonance imaging revealed a full-thickness bone defect in the right anterior iliac crest. A mass was noted in the right gluteus minimus, while a multilocular cystic mass extended from the right iliac crest defect to the right inguinal region. Both the inguinal mass and gluteal mass were removed under general anesthesia. Following histopathological analysis, the gluteal mass was diagnosed as a venous malformation (VM). Based on the patient's clinical course, iliac bone graft harvesting and trauma to the gluteal region triggered hemorrhaging from the VM. Blood components leaked out from the fragile portion of the iliac bone defect, forming a cystic lesion that developed into the inguinal mass. In this case, a coincidental VM resulted in a rare complication of iliac bone graft harvesting. These sequelae could have been avoided by planning for more appropriate ways to collect the grafts.