The Neck: Thyroid Gland

10.1055/b-0034-87906

**Table 4.52 Enlarged thyroid**
Diagnosis	Findings	Comments
Goiter	US: Diffusely enlarged hypoechoic gland with increased vascularity. If multinodular, goiter is enlarged and asymmetrical with several focal nodules of mixed echogenicity.	Correlate with antibody results and NM.
Hemiagenesis	US: unilateral, more common on left.	Due to hypertrophy of single lobe or dysfunction.
Thyroiditis	US: Findings depend on stage, usually diffuse or focal hypoechogenicity and enlargement of both lobes. Doppler shows no increased vascularity.	Clinical signs of thyrotoxicosis in 50%.

**Table 4.53 Thyroid mass**
Diagnosis	Findings	Comments
Cyst (usually colloid)	US: hypo-/anechoic mass. If any solid component, requires work-up for thyroid malignancy. MRI: may appear bright on T1 due to hemorrhage, colloid, or high protein.	Uncommon in young children. True thyroid cysts are rare.
Abscess Fig. 4.172	US: hypoechoic or anechoic mass, ± internal echoes if infected. CT: rim-enhancing mass with central low density.	Rare. Suggests congenital pyriform sinus fistula—correlate with barium swallow or fistulogram.
Adenoma	US: Either increased or decreased echogenicity. Classically have hypoechoic halo around isoechoic mass.	Uncommon. May be single or multiple. May be hyper- or nonfunctioning.
Carcinoma Fig. 4.173	US: Primary imaging modality showing either solid or cystic mass usually hypoechoic but may have hyperechoic calcification. Cervical lymphadenopathy seen in 90%.	Rare. Ninety percent are papillary; three-quarters of cases occur in females. Neck and chest CECT and bone scan are required for staging.