Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Radiation-induced extraskeletal osteosarcoma
- Radiologic Findings
- Fig 1. Chest radiograph shows increased opacity in left upper lung field. The patient has history of bilateral mastectomy.
Fig 2. Non-contrast HRCT shows ossifying mass in left pectoralis muscle.
Fig 3. Lung window setting of the HRCT scan shows fibrotic change in apex of both upper lobes suggesting radiation fibrosis.
The patient received left mastectomy and radiation therapy with a total dose of 5040cGy due to breast cancer 13 years ago. She also received right mastectomy and radiation therapy with a total dose of 6400cGy 8 years age.
- Brief Review
- Radiation-associated sarcoma is a rare but well-known late complication of radiotherapy with a incidence of 0.035% to 0.8%. Generally, a minimum dose of 10?6Gy is postulated to be necessary to induce this complication. The mean latency period is 10?5 years.
The criteria for the diagnosis of postirradiation sarcoma was first proposed by Cahan et al. in 1948 and consisted of (1) history of radiation therapy, (2) sarcoma arising within the radiation field after the radiation has been given, (3) long latency period, and (4) histologic confirmation of the sarcoma.
The long-term risk of developing sarcoma after radiation therapy for breast cancer has been reported as 0.2% for 10 years. The most common soft tissue sarcoma and bone sarcoma to arise in the irradiated conserved breast and the surrounding field are angiosarcoma and osteosarcoma, respectively. Most reported cases of osteosarcoma of the chest wall following irradiation for breast cancer arise from the chest wall skeletal structures.
Radiation-associated extraskeletal osteosarcomas (ESOSs) are reported to range from 3.8% to 10% of all ESOSs and 13% of all radiation induced sarcomas. Extraskeletal osteosarcomas have a local recurrence rate of 26% to 69%, with a 5-year survival rate of 25% to 37%. Survival does not seem to be affected by latency period, location, amount of radiation, or histologic type.
- References
- 1. Orta L, Suprun U, Goldfarb A, et al. Radiation-associated extraskeletal osteosarcoma of the chest wall. Arch Pathol Lab Med 2006; 130: 198-200
2. ninimiya H, Miyoshi T, Shirakusa T, et al. Postradiation sarcoma of the chest wall: report of two cases. Surg Today 2006; 36: 1101-1104
- Keywords