Abstract
Epithelioid angiosarcoma (EA) is a malignant tumor of endothelium origin that most commonly arises in the deep soft tissues of extremities but may occasionally be primary in skin, adrenal gland, and bone. A 72-year-old male presented with a painless enlargement of his thyroid for more than 10 days before hospitalization. A walnut-sized mass in the right thyroid was found simultaneously by palpation and Color Doppler Ultrasound. After a total thyroidectomy was performed, a mass with a size of 4.5 cm × 3.5 cm was found at the lower pole of the right thyroid gland. Histologically, the tumor was diffusely distributed in a sheet-like pattern, with tumor cells being epithelioid. There was extensive coagulative necrosis while no components of papillary carcinoma, follicular carcinoma and insular poorly differentiated carcinoma were noticed. CD31 and vimentin were positive for immunostaining. The diagnosis of primary epithelioid angiosarcoma of right thyroid was then given to the patient. Eleven months after the operation, the patient died from brain metastasis. It is suggested that primary epithelioid angiosarcoma of thyroid, as an extremely rare tumor, have no characteristic clinical manifestations, laboratory and imaging examinations, and the diagnosis mainly depend on its unique clinical pathological features. Although extensive surgical resection is the preferred treatment, the prognosis is still very poor.