Ultrasound and Histological images. (A) Grey-scale ultrasound image of our patient's neck. The image was taken with commercially available 7.5 MHz linear probes and shows a multi-nodular goiter with a right-lobe hypoechoic nodule (about 2 cm in diameter) that has an irregular outline. (B) Invasive fibrous thyroiditis (Riedel's disease). The thyroid gland is replaced by dense keloid-like bands of fibrous tissue with mixed chronic inflammatory cells (lymphocytes and plasma cells).