title: A multinodular goiter as the initial presentation of a renal cell carcinoma harbouring a novel VHL mutation.
abstract: BACKGROUND
  Secondary involvement of the thyroid gland is rare. Often the origin of the tumor is difficult to identify from the material obtained by fine-needle aspiration cytology. Renal cell carcinoma of the clear-cell type is one of the more common carcinomas to metastasize to the thyroid gland. Somatic mutations of the von Hippel-Lindau tumor suppressor gene are associated with the sporadic form of this tumor. We aimed to illustrate the potential utility of DNA based technologies to search for specific molecular markers in order to establish the anatomic site of origin.
  
  
  METHODS
  A 54-yr-old Caucasian male complaining of a rapidly increasing neck tumor was diagnosed as having a clear-cell tumor by fine-needle aspiration cytology. A positive staining for cytokeratin as well as for vimentin and CD10 in the absence of staining for thyroglobulin, calcitonin and TTF1 suggested a renal origin confirmed by computed tomography. Using frozen RNA, obtained from cells left inside the needle used for fine needle aspiration cytology, it was possible to identify a somatic mutation (680 delA) in the VHL gene.
  
  
  CONCLUSIONS
  In the presence of a clear-cell tumor of the thyroid gland, screening for somatic mutations in the VHL gene in material derived from thyroid aspirates might provide additional information to immunocytochemical studies and therefore plays a contributory role to establish the final diagnosis. Moreover, in a near future, this piece of information might be useful to define a targeted therapy.
authors.affiliation: Serviço de Endocrinologia, Instituto Português de Oncologia Francisco Gentil, Lisboa, Portugal. mjbugalho@ipolisboa.min-saude.pt
authors.forename: Maria João M
authors.initials: MJ
authors.lastname: Bugalho
authors.forename: Evelina
authors.initials: E
authors.lastname: Mendonça
authors.forename: Patrícia
authors.initials: P
authors.lastname: Costa
authors.forename: Jorge Rosa
authors.initials: JR
authors.lastname: Santos
authors.forename: Eduardo
authors.initials: E
authors.lastname: Silva
authors.forename: Ana Luísa
authors.initials: AL
authors.lastname: Catarino
authors.forename: Luís G
authors.initials: LG
authors.lastname: Sobrinho