Immunohistochemical characterization of thyroid gland angiomatoid tumors.

The histogenesis of thyroid gland angiomatoid tumors, probably as a primary angiosarcoma, has been a controversy for many years. These tumors may be variants of undifferentiated (anaplastic) carcinomas. We report a thyroid gland angiomatoid carcinoma in a 61-year-old African American male. The tumor had a heterogeneous pattern with both sarcomatous and epithelioid areas. Tumor cells lined some vascular-like spaces and others had intracytoplasmic lumens containing red blood cells. The tumor cells were found to express multiple endothelial (factor VIII-related antigen, CD31, CD34, and Ulex europaeus I lectin) and epithelial (cytokeratin and epithelial membrane antigen) markers as well as thyroglobulin by immunohistochemistry. This rare presentation demonstrates the heterogeneous nature of thyroid gland angiomatoid carcinoma with both epithelial and endothelial differentiation. Copyright 2000 Academic Press.