Cytology of angiosarcoma. Findings in fourteen fine-needle aspiration biopsy specimens and one pleural fluid specimen.

We report the cytologic features of 15 cases of angiosarcoma from various sites and include 14 fine-needle aspiration (FNA) biopsy specimens and 1 pleural fluid specimen. Six were initial diagnoses with histologic confirmation; an additional case in the liver was an initial diagnosis without tissue confirmation. One case represented lymph node metastasis from a primary prostatic epithelioid angiosarcoma. In 10 cases, immunohistochemical staining for factor VIII-related antigen, CD34, CD31, or Ulex europaeus agglutinin I was performed on the cytology or histology specimen. The aspirates varied in cellularity, and the degree of nuclear atypia ranged from relatively bland in a case of low-grade angiosarcoma of the prostate to highly pleomorphic in a lymph node metastasis from a facial cutaneous angiosarcoma. Vasoformative features such as intracellular RBCs, well-formed vessels, attempts at microacinar/lumen formation, and intracytoplasmic lumens were variably present. The background was bloody in all specimens, with necrosis in rare cases. This cytologic series emphasizes that the cytologic features are heterogeneous but that the diagnosis can be suggested by fine-needle aspiration (FNA) when vasoformative features are present. The diagnosis can be made conclusively by FNA with immunocytochemical confirmation of endothelial differentiation.