From 1976 to 1989 the authors treated 21 infants and children with malignant tumors of the chest wall. Fifteen were classified as Askin's tumors or Ewing's sarcoma, which we now consider as a single entity of primitive neuroectodermal origin. They are infrequent but highly aggressive tumors that involve the chest wall in children. Five patients presented with metastatic disease; despite chemotherapy and radiotherapy, all succumbed to progressive disease. Ten patients with localized disease received combined modality therapy including surgical resection (three after initial chemotherapy), radiotherapy, and chemotherapy. Surgery involved resection of the mass and up to three ribs, with prosthetic mesh reconstruction in one patient. Six of the 10 patients with localized disease are continuously disease-free 3.5 to 9 years (median, 5 years) following diagnosis. No patient had local recurrence. Of the four whose treatment failed, one died (free of disease) from complications after resection of an extensive primary tumor. In the second patient, acute monocytic leukemia developed shortly after relapse in a distant bone site. The patient died during induction for the leukemia. In the other two patients, hilar and carinal lymph node relapse occurred 68 and 80 months after initial treatment. One of the patients is considered in second remission (now 105 months later) after further chemotherapy (Adria-VAC) and radiation; the other succumbed to secondary relapse 17 months after second remission was achieved through chemotherapy, radiation, and surgery. Initial percutaneous needle biopsy of the large lesions has provided adequate material for histological, immunohistochemical, cytogenetic and ultrastructural diagnosis, and permitted initial chemotherapy before proceeding to surgical resection.(ABSTRACT TRUNCATED AT 250 WORDS)