Inspissated colloid

Last revised by Daniel J Bell on 29 Nov 2021

Inspissated colloid (colloid crystals) in a thyroid nodule leads to focal hyperechogenic foci, which can potentially be confused with microcalcifications.

Radiographic features


Inspissated colloid can vary in size and tend to be larger than microcalcifications, however, there is overlap in size between the two entities.

Treatment and prognosis

Differentiation between inspissated colloid and microcalcifications in a thyroid nodule is important. Inspissated colloid is not associated with malignancy and fine needle aspiration (FNA) is unnecessary. Microcalcifications are associated with papillary thyroid cancer and FNA is almost always indicated for nodules with microcalcifications.

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