A 13-year-old healthy girl presented with dizziness and palpitations, found to have a left atrial mass. An 8 cm tumor was removed. Pathology confirmed leiomyosarcoma, Grade 3 with positive margins. She was treated with ifosfamide and doxorubicin prior to radiation with concurrent ifosfamide alone. She was treated to 66 Gy in 33 fractions to the operative bed. Prospectively graded toxicities included Gr 2 esophagitis and Gr 1 anorexia, dermatitis and fatigue. She completed a total of 6 cycles of ifosfamide. One year after treatment she had no evidence of disease with normal ECHO and no cardiac, pulmonary or esophageal symptoms.