Ultrasound scanning (Fig. 16.18) differentiates between cysts and solid lesions; differentiated carcinomas are only very occasionally cystic. A nodule that is ΓÇÿcoldΓÇÖ on scan may prove to be a benign cyst, a colloid nodule, an adenoma, part of an asymmetric Hashimoto's goitre, a differentiated carcinoma, or a medullary carcinoma.
