Radiation induced osteosarcoma of the sacrum following radiation of an undiagnosed bone lesion.

Years ago a 20-year-old patient presented with low back pain. Radiologically a cystic lesion of the sacrum was found and interpreted as malignant tumor. Without biopsy and histological diagnosis the patient was given radiation therapy with 21 000 rad. One year later a similar lesion was radiated in the left femoral neck. A pathological fracture ensued recessitating several operations. Twenty years after initial radiation therapy the patient developed a rapidly growing tumor of the sacrum, metastasizing to the lungs. One year later he died.