Angiosarcoma of the larynx.

The morphological and immunohistochemical features of a laryngeal angiosarcoma are described. Initially, the tumour was interpreted as a poorly differentiated squamous cell carcinoma. The laryngectomy specimen contained an extensive and haemorrhagic tumour consisting of irregular and dissecting vascular spaces delineated by pleomorphic endothelial cells. In addition to these obvious angiosarcomatous areas, islands of more compact growing tumour cells were present, reminiscent of a poorly differentiated squamous cell carcinoma. On immunohistochemistry, the tumour cells expressed factor VIII, Ulex europaeus I lectin, CD31 and vimentin. There was no expression of cytokeratin or epithelial membrane antigen. Angiosarcoma of the larynx is very rare and should be differentiated from a pseudo-angiosarcomatous carcinoma.