What is the condition involving the pelvic bones and what is the associated complication?
Paget disease with left iliac bone osteosarcoma.
Lower lumbar spine and pelvic Paget disease, left hemipelvis worse than right. In the left ilium, along the pelvic surface, enlarging enhancing soft tissue mass is again demonstrated with associated periosteal new bone formation. This has increased from 6.4 x 1.7 x 7.7 cm (2 years ago) to 7.5 x 2.4 x 9.9 cm (6 months ago) to currently 8 x 2.6 x 11 cm.
Conclusion: Enlarging soft tissue mass related to Paget disease of the left hemipelvis remains concerning for sarcomatous transformation. Metastasis is felt less likely. No other potential sites of metastatic disease.