title: Malignant paraganglioma in children treated with embolization prior to surgical excision.
abstract: BACKGROUND
  Paragangliomas (PGL) are rare tumors derived from neural crest cells, whose origins may vary along the chain of the sympathetic nervous system. Such tumors are often characterized by secretion of catecholamines, but sometimes they are biochemically inactive, which makes diagnosis often challenging. Malignant paraganglioma is defined by the presence of this tumor at sites where chromaffin cells are usually not found or by local invasion of the primary tumor. Recurrence, either regional or metastatic, usually occurs within 5 years of the initial complete resection but long-term recurrence is also described. Malignancy is often linked to a SDHB mutation. Preoperative embolization has been applied in the surgical management of PGLs with the objective to decrease intra-operative blood loss and surgery length without complications.
  
  
  METHODS
  We report two cases of patients with abdominal or pelvic malignant PGLs who have been treated surgically at our center after preoperative embolization. Surgery was a very challenging procedure with multiple surgical teams involved and embolization did not prevent major blood loss and intraoperative complications. Patients required adjuvant treatment with either chemotherapy or radiotherapy.
  
  
  CONCLUSIONS
  Many studies in the adult population have established recommendations for the diagnosis and therapeutic management of PGL, but few studies concern the pediatric population. Because malignant PGL is more important in the pediatric population, screening and early diagnosis of PGL is advisable in children with genetic predisposing. Surgical resection is the mainstay of treatment, but a multimodal approach is often required due to the complexity of cases.  The role of preoperative embolization is not established and in our experience it has provided little benefit and major complications.
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil. mirandaedp@gmail.com.
authors.forename: Eduardo
authors.initials: E
authors.lastname: de Paula Miranda
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Roberto Iglesias
authors.initials: RI
authors.lastname: Lopes
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Guilherme Philomeno
authors.initials: GP
authors.lastname: Padovani
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Paulo Renato Marcelo
authors.initials: PR
authors.lastname: Moscardi
authors.affiliation: Department of Anesthesiology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Fernanda Gardini Maciel
authors.initials: FG
authors.lastname: Nishimura
authors.affiliation: Division of Endocrinology and Metabolism, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Berenice Bilharinho
authors.initials: BB
authors.lastname: de Mendonça
authors.affiliation: Department of Radiology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Francisco Cesar
authors.initials: FC
authors.lastname: Carnevale
authors.affiliation: Department of Pediatrics, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Lilian Maria
authors.initials: LM
authors.lastname: Cristofani
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Ricardo Jordão
authors.initials: RJ
authors.lastname: Duarte
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Miguel
authors.initials: M
authors.lastname: Srougi
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Francisco Tibor
authors.initials: FT
authors.lastname: Denes
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D004621:Embolization, Therapeutic / Q000009:adverse effects*; D006801:Humans; D008297:Male; D010235:Paraganglioma / Q000209:etiology* / Q000473:pathology; D010386:Pelvic Neoplasms / Q000628:therapy*; D011300:Preoperative Care; D011379:Prognosis
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