KEY FACTS
Terminology
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Chronic, autoimmune-mediated lymphocytic inflammation of thyroid gland
Imaging
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Features vary with stages of disease (acute, chronic, end stage) and extent of involvement (diffuse or focal)
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Acute diffuse: Enlarged heterogeneous hypoechoic thyroid with lobulated contour; multiple hypoechoic micronodules throughout with intervening echogenic septa
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Acute focal: Discrete, hypoechoic or hyperechoic nodules against normal or altered background thyroid, ± calcifications, halo
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End stage: Small, hypoechoic gland with heterogeneous echo pattern
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Color Doppler: Vascularity depends on stage and type of involvement
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Acute focal/diffuse: Variable vascularity, focal nodule may mimic benign/malignant thyroid nodule
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Enlarged nodes are common, especially in central neck
Top Differential Diagnoses
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Thyroid Non-Hodgkin lymphoma
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Graves disease
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de Quervain thyroiditis
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Riedel thyroiditis (invasive fibrosing thyroiditis)
Clinical Issues
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Most common cause of hypothyroidism in USA
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Gradual, painless enlargement of thyroid with later atrophy
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↑ thyroid peroxidase and antithyroglobulin antibodies
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↑ risk of non-Hodgkin lymphoma and papillary carcinoma
Scanning Tips
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Be on lookout for developing cancer: Look for nodules that are different from others and for those that are enlarging or contain microcalcifications
