title: Primary Ewing's sarcoma/primitive neuroectodermal tumor of the urogenital tract in children.
abstract: BACKGROUND
  Primary Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) of urogenital tract is a rare condition with non-specific clinical presentations, which can make it difficult to diagnose. In this study, we summarize the clinical presentation, pathological features, therapeutic strategies, and prognosis of ES/PNET.
  
  
  METHODS
  Clinical information on two cases of ES/PNET in the penis and ureter was analyzed, and relevant literature was reviewed.
  
  
  RESULTS
  ES/PNET was confirmed pathologically, immunohistochemically and via molecular biology techniques in the penis (n=1) and ureter (n=1). In one case, a tumor was found at the base of penis, which had invaded the corpus cavernosum, and resulted in a massive enlargement of the penis. This tumor was initially diagnosed as an endocrine disorder. However, a confirmed diagnosis was made 11 months later when massive metastases in both lungs were noted. A tumor biopsy was performed to confirm the diagnosis, and chemotherapy with a CAV (cyclophosphamide+doxorubicin+vincristine)+IE (ifosfamide+etoposide) regimen for 9 months was prescribed. In the second case, a child was admitted due to abdominal pain and a hydroureter in the right kidney, as determined by ultrasonography. A tumor was found in the right ureter at the level of iliac vessels. Removal of the tumor and ureteral anastomosis were performed, and chemotherapy with CAV+IE for 8 months were prescribed. Both patients are currently being followed-up closely.
  
  
  CONCLUSIONS
  ES/PNET is a highly malignant tumor and has poor prognosis. Pre-operative diagnosis of ES/PNET of urogenital tract is difficult and largely depends on pathology, immunohistochemistry, and, if applicable, molecular biology. Comprehensive therapy may include surgery, chemotherapy and radiotherapy.
authors.affiliation: National Key Discipline of Pediatrics, Ministry of Education, Department of Urology, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
authors.forename: Hong-cheng
authors.initials: HC
authors.lastname: Song
authors.forename: Ning
authors.initials: N
authors.lastname: Sun
authors.forename: Wei-ping
authors.initials: WP
authors.lastname: Zhang
authors.forename: Cheng-ru
authors.initials: CR
authors.lastname: Huang
mesh_terms: D002648:Child; D002675:Child, Preschool; D006801:Humans; D008297:Male; D018241:Neuroectodermal Tumors, Primitive, Peripheral / Q000175:diagnosis* / Q000601:surgery; D012512:Sarcoma, Ewing / Q000175:diagnosis* / Q000601:surgery; D014565:Urogenital Neoplasms / Q000175:diagnosis* / Q000601:surgery