Unusual presentation of extraosseous metastases on bone scintigraphy

Osteosarcoma metastases frequently occur in the lungs or the skeleton. Bone scans play an important role in disease staging by identifying other skip areas of skeletal involvement as well as extraosseous metastases. We report a case of aggressive osteosarcoma, with bone metastases and extraosseous areas of involvement in the lungs, distant lymph nodes, and peritoneal and subcutaneous metastasis seen in a preoperative Tc-99m methylene diphosphonate bone scan. These findings were confirmed with histology and correlative cross-sectional imaging.