title: [Primitive neuroectodermal tumors: difficult tumors versus modern oncology].
abstract: BACKGROUND
  Primitive peripheral neuroectodermal tumours (PNET) are rare masses and form part of the group of round small cell tumours which include a wide range of highly aggressive neoplasias such as Ewing's sarcoma, neuroblastoma, lymphoma and rhabdomyosarcoma. PNET present the same cell line as the tumours presented by F. Askin in 1979, both located in the thoracic-pulmonary region.
  
  
  METHODS
  Of the last 26 thoracic neuroblastomas and 11 mediastinal-thoracic sarcomas treated at our centre, we observed 5 PNET in children with a mean age of 12 years (range: 9-14 years). These patients presented a thoracic mass infiltrating sternum, clavicle, supraspinal muscle or, in two cases, a left lateral or paravertebral intrathoracic mass. The time elapsed between clinical observation and diagnosis was 6 weeks. Diagnosis was established by chest X-Ray, CT, bone scintigraphy, immunocytochemistry and cytology. Aggressive local treatment associated with stage IV SIOP chemotherapy for rhabdomyosarcoma was applied in all cases to prevent metastasis.
  
  
  RESULTS
  Of the five PNET treated, one 16-year-old patient died (4 y 5 m post-diagnosis) from bone marrow infiltration which had evolved badly from the beginning. The remaining patients are disease-free. One patient who did not undergo surgery relapsed 1 year and the half after completing chemotherapy. He then underwent resection of the cranial portion of the sternum and substitution with iliac graft from the tissue bank.
  
  
  CONCLUSIONS
  PNET manifest clearly some of the characteristics of current paediatric oncology. These tumours are easily misdiagnosed and at present may be differentiated by new diagnostic methods (immunohistochemistry, cytogenetics, hybridomas, molecular genetics), with the aim of selecting the most adequate treatment and consequently improving the prognosis of these aggressive embryonary tumours.
authors.affiliation: Departamento de Cirugía Pediátrica, Hospital Materno-Infantil Vall d'Hebron.
authors.forename: V
authors.initials: V
authors.lastname: Martínez Ibáñez
authors.forename: P
authors.initials: P
authors.lastname: Abad
authors.forename: N
authors.initials: N
authors.lastname: Torán
authors.forename: C I
authors.initials: CI
authors.lastname: González
authors.forename: J
authors.initials: J
authors.lastname: Sánchez de Toledo
authors.forename: A
authors.initials: A
authors.lastname: Marqués
authors.forename: J
authors.initials: J
authors.lastname: Boix-Ochoa
mesh_terms: D000293:Adolescent; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D018242:Neuroectodermal Tumors, Primitive / Q000175:diagnosis*
vernacular_title: Tumores neuroectodérmicos primitivos: tumores difíciles versus oncología moderna.