Growth patterns of benign and malignant thyroid tumors estimated by CT

Thyroid tumors affect adjacent structures and reveal their nature as they grow. Differences in benign and malignant tumor growth patterns were studied by CT. Twenty-nine benign (follicular adenoma) and 29 malignant (papillary carcinoma) tumors with their findings were arranged according to size to speculate on how they grew. Benign tumors grew expansively and made a beak-like appearance in the marginal thyroid tissue (beak sign). They displaced vessels but kept a fat plane or deep sulcus between them (sulcus sign). Malignant tumors, on the other hand, grew invasively and reached the trachea rapidly without the beak sign. They destroyed the fat plane and contacted the vessels without the sulcus sign. Expansive and invasive growth forms of benign and malignant thyroid tumors could be represented schematically.