A case of radiation-induced sarcoma of the chest wall is reported. Twenty-seven 
years 11 months after orthovoltage radiotherapy of the right breast a 
69-year-old woman developed a radiation-induced osteosarcoma of the right 
thoracic wall. Initial diagnosis has been T-cell lymphoma of the skin. The right 
breast was irradiated with tangential fields and a total dose of 40 Gy, 2 
Gy/day, 5 days a week. Orthovoltage treatment was performed in two courses of 20 
Gy, 3 months apart. The clinical appearance of the secondary sarcoma was a 
diffuse infiltrated area in the irradiated breast which seemed to be fixed to 
the chest wall. Magnetic resonance imaging (MRI) demonstrated a mass in the 
right anterior thoracic wall which destroyed the fourth to the sixth rib. The 
tumor infiltrated the thoracic wall, including subcutaneous tissue and 
pericardium, as well as extending into the subphrenic space. Biopsy of the 
lesion revealed a poorly differentiated osteosarcoma. The patient's general 
condition precluded surgical or chemotherapeutic intervention; she died due to a 
cerebral stroke 6 months later. This case fulfilled all criteria for 
radiation-induced sarcoma, as there was a prior history of radiotherapy, latency 
period of several years, development of sarcoma within the irradiated field, and 
histologic confirmation of sarcoma.