title: Malignant ectomesenchymoma in children and adolescents: report from the Cooperative Weichteilsarkom Studiengruppe (CWS).
abstract: BACKGROUND
  Malignant ectomesenchymoma (MEM) is a soft tissue tumor with heterologous rhabdomyoblastic components believed to arise from pluripotent migratory neural crest cells. To date merely 50 cases have been published and the knowledge about the course of disease and optimal treatment is limited.
  
  
  METHODS
  Six patients with MEM were registered 1996-2009. The diagnosis was confirmed according to current criteria. Their treatment and outcome was analyzed.
  
  
  RESULTS
  The median age of the three females and three males was 0.6 years (range, 0.2-13.5). The mesenchymal component in all tumors was rhabdomyosarcoma (RMS), the neural component ganglioneuroblastoma/neuroblastoma (n = 5) and peripheral primitive neuroectodermal tumor in one case. Five patients presented with localized, one with metastatic disease. All but one patient received multiagent chemotherapy during their initial treatment. The tumors of 4/5 patients with localized MEM were at least grossly resected at best surgery; the patient without gross resection was additionally irradiated. Three of four evaluable tumors responded well to induction chemotherapy. All patients achieved a first complete remission (CR), but three recurrences (two local, one systemic) occurred. The individual with metastatic MEM did not survive, but all five patients with localized MEM are currently alive in CR with a median follow-up of 5 years (range: 2.1-13.7).
  
  
  CONCLUSIONS
  Risk-factors and outcome of MEM appear to be comparable with other highly malignant pediatric soft tissue sarcoma when a multimodal treatment strategy including chemotherapy and adequate local treatment is pursued. We propose that treatment of patients with MEM be done according to pediatric protocols similar to other rhabdomyosarcoma-like soft tissue sarcoma.
authors.affiliation: Olgahospital, Pediatrics 5 (Oncology, Hematology, Immunology, Rheumatology, Gastroenterology and General Pediatrics), Klinikum Stuttgart, Germany. tobias.dantonello@olgahospital-stuttgart.de
authors.forename: Tobias M
authors.initials: TM
authors.lastname: Dantonello
authors.forename: Ivo
authors.initials: I
authors.lastname: Leuschner
authors.forename: Christian
authors.initials: C
authors.lastname: Vokuhl
authors.forename: Stefan
authors.initials: S
authors.lastname: Gfroerer
authors.forename: Andreas
authors.initials: A
authors.lastname: Schuck
authors.forename: Stefanie
authors.initials: S
authors.lastname: Kube
authors.forename: Michaela
authors.initials: M
authors.lastname: Nathrath
authors.forename: Benedikt
authors.initials: B
authors.lastname: Bernbeck
authors.forename: Peter
authors.initials: P
authors.lastname: Kaatsch
authors.forename: Niklas
authors.initials: N
authors.lastname: Pal
authors.forename: Gustaf
authors.initials: G
authors.lastname: Ljungman
authors.forename: Stefan S
authors.initials: SS
authors.lastname: Bielack
authors.forename: Thomas
authors.initials: T
authors.lastname: Klingebiel
authors.forename: Ewa
authors.initials: E
authors.lastname: Koscielniak
mesh_terms: D000293:Adolescent; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D018572:Disease-Free Survival; D004475:Ectoderm / Q000473:pathology*; D005260:Female; D006801:Humans; D007223:Infant; D053208:Kaplan-Meier Estimate; D008297:Male; D008637:Mesenchymoma / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D058028:Research Report; D012509:Sarcoma / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*