Spiculated periosteal reaction in metastatic disease resembling osteosarcoma

Sixteen cases of metastatic bone deposits presenting with sunburst spiculated periosteal reaction are presented. The most common origin was from prostatic carcinoma followed by neuroblastoma. A moderate soft tissue mass component was seen in 70% of the cases. The possible pathophysiologic reasons for this type of periosteal reaction are presented. The differential diagnosis is outlined.