Inspissated colloid (colloid crystals) in a thyroid nodule leads to focal hyperechogenic foci, which can potentially be confused with microcalcifications.
- hyperechoic focus in a thyroid nodule
reverberation artifact / comet-tail artifact
- this feature is the most reliable in differentiating inspissated colloid from microcalcifications
Inspissated colloid can vary in size and tend to be larger than microcalcifications. There is overlap in size between the two entities, however.
Treatment and prognosis
It is important to try to differentiate between inspissated colloid and microcalcifications in a thyroid nodule. Inspissated colloid is not associated with malignancy and fine needle aspiration (FNA) is uncessary. Microcalcifications are associated with papillary thyroid cancer and FNA is almost always indicated for nodules with microcalcifications.
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