The existence of
angiosarcoma of the thyroid gland and its relation to angiomatoid
carcinoma have been debated. The authors reviewed eight angiomatoid
thyroid neoplasms. Controls consisted of six sarcomatoid
thyroid carcinomas without angiomatoid features and an
angiosarcoma metastatic to the thyroid gland. All eight angiomatoid
neoplasms consisted of epithelioid cells with prominent eosinophilic cytoplasm lining vascularlike spaces. All eight expressed
vimentin. Four
tumors were predominantly angiosarcomalike
neoplasms, based on staining for
factor VIII-related antigen (three of four), CD31 (four of four), CD34 (one of four), and
Ulex europaeus I lectin (four of four); they lacked epithelial markers other than
cytokeratin (two of four). Four
tumors were designated as angiomatoid
carcinomas, based on staining for multiple epithelial markers:
cytokeratin (four of four),
epithelial membrane antigen (three of four),
thyroglobulin (three of four). Three angiomatoid
carcinomas also expressed or labeled with one or more vascular markers: CD34 (one of four), CD31 (two of four),
Ulex europaeus I lectin (one of four),
factor VIII-related antigen (one of four). The metastatic
angiosarcoma to the thyroid gland labeled for
factor VIII-related antigen,
vimentin, CD31, and with
Ulex europaeus I lectin. It did not express CD34. The six sarcomatoid
carcinomas without angiomatoid features stained for
cytokeratin (four of six),
epithelial membrane antigen (one of six), and
vimentin (six of six). None labeled for
thyroglobulin,
factor VIII-related antigen, CD31, CD34, or with
Ulex europaeus I lectin. Angiomatoid
carcinomas of the thyroid gland exhibit both epithelial and endothelial features. "
Angiosarcoma" may represent the extreme in this spectrum of endothelial differentiation. All
tumors behaved in a similar clinical fashion characterized by persistent local disease, widespread
metastases and poor prognosis.