title: Cytologic findings of epithelioid angiosarcoma of the thyroid. A case report.
abstract: BACKGROUND
  Angiosarcoma of the thyroid is a rare and aggressive tumor and occurs mainly in patients from central Europe, especially the alpine region. The fine needle aspiration findings of a keratin-positive epithelioid angiosarcoma of the thyroid occurring in a nonmountainous area in South America is described.
  
  
  METHODS
  A 65-year-old male from São Paulo, Brazil, presented with a mass in the anterior part of the neck with progressive enlargement for three months. The cytologic findings on the fine needle aspirate were a cellular smear composed of single cells and small clusters of neoplastic cells, oval and round. Cell borders were indistinct, and the cytoplasm was vacuolated. The nuclei were eccentrically located, with irregular nuclear membranes; single, prominent nucleoli; and a coarse chromatin pattern. Features suggestive of intracytoplasmic lumens were identified. Open surgical biopsy demonstrated a tumor infiltrating the thyroid gland and composed of large, round, atypical epithelioid cells lining vascular spaces. These neoplastic cells were immunoreactive for AE1:AE3, CK7, vimentin, CD31 and factor VIII.
  
  
  CONCLUSIONS
  Epithelioid angiosarcoma should be considered in the differential diagnosis of epithelioid neoplasms of the thyroid. An immunohistochemical panel should include vascular markers even in the presence of immunoreactivity for epithelial markers.
authors.affiliation: Department of Anatomic Pathology, Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil. lino@mskcc.org
authors.forename: Oscar
authors.initials: O
authors.lastname: Lin
authors.forename: Rene
authors.initials: R
authors.lastname: Gerhard
authors.forename: Sheila Aparecida
authors.initials: SA
authors.lastname: Coelho Siqueira
authors.forename: Ines Vieira
authors.initials: IV
authors.lastname: de Castro
mesh_terms: D000368:Aged; D001457:Anion Exchange Protein 1, Erythrocyte / Q000032:analysis / Q000276:immunology; D017920:Antiporters / Q000032:analysis / Q000276:immunology; D001707:Biopsy, Needle; D003937:Diagnosis, Differential; D015622:Epithelioid Cells / Q000473:pathology* / Q000648:ultrastructure; D005169:Factor VIII / Q000032:analysis / Q000276:immunology; D006258:Head and Neck Neoplasms / Q000473:pathology / Q000648:ultrastructure; D006394:Hemangiosarcoma / Q000473:pathology* / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis / Q000276:immunology; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000648:ultrastructure; D014746:Vimentin / Q000032:analysis / Q000276:immunology
chemical_list: D001457:Anion Exchange Protein 1, Erythrocyte; D017920:Antiporters; D019408:Platelet Endothelial Cell Adhesion Molecule-1; C489237:SLC4A3 protein, human; D014746:Vimentin; D005169:Factor VIII