Hemangiosarcoma of the thyroid gland. Histological diagnosis problems.

A bleeding tumor of the thyroid gland in a 69-year-old woman is presented. Histologically, it was a hemangiosarcoma with proliferation and vessel neoformation: vascular-like clefts or distinct capillaries with tumoral endo- and perithelial structures were present. With reference to the published data, problems of differential diagnosis in the undifferentiated and giant cell carcinomas of the thyroid gland are discussed.