Nonshadowing echogenic foci in thyroid nodules: are certain appearances enough to avoid thyroid biopsy?

Area of Science:

• Radiology
• Oncology
• Endocrinology

Background:

• Nonshadowing echogenic foci are common ultrasound findings in thyroid nodules.
• Classification and clinical significance of these foci, especially regarding malignancy, require further elucidation.

Purpose of the Study:

• To classify nonshadowing echogenic foci in thyroid nodules.
• To investigate the association between different types of echogenic foci and malignancy.

Main Methods:

• Retrospective review of 371 thyroid nodules in 189 patients.
• Classification of echogenic foci into four types: comet tail artifact, linear/brightly echogenic, round/indeterminate, and microcalcifications.
• Correlation of echogenic foci types with pathologic results and imaging follow-up.

Main Results:

• Nodules with comet tail artifact (19) and linear/brightly echogenic foci (29) showed no malignancy.
• Round/indeterminate echogenic foci (24) were associated with a 4% malignancy rate (papillary carcinoma).
• Microcalcifications (14) showed a 29% malignancy rate (papillary thyroid cancer).

Conclusions:

• Nonshadowing, brightly echogenic linear foci, with or without a comet tail artifact, may indicate a benign thyroid nodule.
• Further studies are necessary to validate these findings for clinical use in thyroid nodule assessment.