Colloid nodule (thyroid)

Colloid nodules are non-neoplastic benign nodules occurring within the thyroid gland. They form the vast majority of nodular thyroid disease.

Pathology

Colloid nodules are composed of irregularly enlarged follicles containing abundant colloid. Some colloid nodules can be cystic (cystic colloid nodule) and may contain areas of necrosis, hemorrhage and/or calcification. A colloid nodule may be single or multiple and can vary considerably in size.

Radiographic features

Ultrasound

• iso- to hypoechoic
• may have internal cystic or heterogeneous change
• may have calcification
• multiple echogenic foci (of inspissated colloid) with comet tail artifact