title: Should extragonadal germ cell tumors be included in studies of families with testicular germ cell tumors?
abstract: BACKGROUND
  Family history is among the few established risk factors for testicular germ cell tumor (TGCT). Approximately 1.4% of newly diagnosed TGCT patients report a positive family history of TGCT. Sons and siblings of TGCT patients have four- to six fold and eight- to tenfold increase in TGCT risk, respectively. In twins of men with TGCT the relative risk of testicular cancer is 37.5 (12.3-115.6). Nevertheless, information about the occurrence of TGCT in relatives of patients with extragonadal germ cell tumor is limited.
  
  
  METHODS
  A 24 year-old male patient was diagnosed with a mediastinum tumor and was submitted to image-guided biopsy, which revealed a seminoma. Two months later, his non-identical asymptomatic twin brother was submitted to an elective ultrasound of the testes, which showed a left testicular mass of 4.2 cm. This patient underwent orchiectomy revealing a seminoma of the left testis. There are no other cases of seminoma or other types of cancers reported in first-degree relatives in this family.
  
  
  CONCLUSIONS
  Although familial aggregations of TGCT have been well described, to the best of our knowledge, no data concerning the association of gonadal and extragonadal germ cell tumor in relatives has been previously reported. Further investigation on this association is warranted and may help in improving our knowledge of familial pattern inheritance.
authors.affiliation: Instituto do Câncer do Estado de São Paulo, Faculdade de Medicina da Universidade de São Paulo, Av, Dr, Arnaldo 251, São Paulo ZIP 01246-000, Brazil. rodrigoscg@usp.br.
authors.forename: Rodrigo Santa Cruz
authors.initials: RS
authors.lastname: Guindalini
authors.forename: Edite Paulo
authors.initials: EP
authors.lastname: de Oliveira
authors.forename: Marina Cavalcanto Moroja
authors.initials: MC
authors.lastname: Silvino
authors.forename: Paulo Marcelo
authors.initials: PM
authors.lastname: Hoff
authors.forename: Bernardo
authors.initials: B
authors.lastname: Garicochea