title: Fine needle aspiration cytology of a thyroid metastasis of metaplastic breast carcinoma: a case report.
abstract: BACKGROUND
  Metaplastic breast carcinoma is defined as mesenchymal and/or squamous cell components associated with ductal carcinoma. Because of the heterogeneous nature of this tumor, cytologic interpretation on fine needle aspirates can be quite challenging. This is especially true of metastatic lesions of this rare tumor type. Metastasis to the thyroid has not been previously reported.
  
  
  METHODS
  A 57-year-old woman with a history of metaplastic breast carcinoma for which she underwent mastectomy, chemotherapy and radiation therapy 2 years earlier presented with a fast-growing left thyroid mass with progressive hoarseness and dysphasia. Clinical presentation and findings from a neck computed tomographic scan were strongly suggestive of a primary thyroid malignancy. The aspirate specimen was composed of scant, highly atypical epithelial cells in a background of an abundant chondromyxoid matrix and scattered, benign follicular cells. A literature review confirmed the novelty of this case.
  
  
  CONCLUSIONS
  This case emphasizes the value of clinical information and the importance of generous sampling in achieving a correct diagnosis of metastatic metaplastic carcinoma.
authors.affiliation: Departmnent of Pathology, Unit 53, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030, USA. yungong@mdanderson.org
authors.forename: Yun
authors.initials: Y
authors.lastname: Gong
authors.forename: Mehri
authors.initials: M
authors.lastname: Jalali
authors.forename: Gregg
authors.initials: G
authors.lastname: Staerkel
mesh_terms: D044963:Biopsy, Fine-Needle; D001943:Breast Neoplasms / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology* / Q000556:secondary*; D005260:Female; D006801:Humans; D008875:Middle Aged; D013961:Thyroid Gland / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000556:secondary*