Radiation-associated sarcomas are rare and aggressive types of sarcomas that can occur after exposure to ionizing radiation. We examine a case of radiation-associated undifferentiated/unclassified soft-tissue sarcoma with primary disease in the chest wall. The optimal treatment of these patients is surgical resection if possible; however, the role of chemotherapy has not been well defined. The patient described herein had a central tumor in the chest wall. Since many of these patients have borderline resectable tumors, the use of neoadjuvant chemotherapy may be helpful to downstage the tumors for possible surgical resection. In this case, doxorubicin plus ifosfamide chemotherapy was employed with a favorable therapeutic effect prior to being resected. To our knowledge this is the first report of greater than 90% necrosis in a patient with radiation-associated undifferentiated/unclassified soft-tissue sarcoma treated with chemotherapy for a borderline resectable mass.