Second malignant neoplasms (SMN) in late childhood or young adulthood in individuals who have been successfully treated for an initial malignancy have emerged as a late effect of therapy in survivors of childhood cancer. Although radiation therapy is frequently implicated, chemotherapy with alkylating agents and antimetabolites has also been associated with SMN. Soft tissue sarcomas are among the most frequent primary malignancies complicated by a SMN and account for a majority of nonhematolymphoid SMN. We present the clinical and pathologic findings in a patient who had a peripheral neuroepithelioma (primitive neuroectodermal tumor, PNET) of the soft tissues diagnosed at 17 years of age, was treated with high-dose irradiation and multidrug chemotherapy, and developed an angiosarcoma 14 years later. This case represents an uncommon combination of mesenchymal malignancies in a young patient with an unusually favorable clinical course following the diagnosis of PNET.