Yonsei Med J.  2012 Jul;53(4):812-819. 10.3349/ymj.2012.53.4.812.

Mixed Echoic Thyroid Nodules on Ultrasound: Approach to Management

• Sohn YM
• Yoon JH
• Moon HJ
• Kim EK
• Kwak JY

• KMID: 1716883
• DOI: http://doi.org/10.3349/ymj.2012.53.4.812

Abstract

PURPOSE
To evaluate malignancy risk according to ultrasound (US) features and size change on follow-up US in mixed echoic thyroid nodules and to suggest management guidelines thereof.
MATERIALS AND METHODS
Among patients who underwent US-guided fine needle aspiration biopsy, 316 mixed echoic nodules in 303 patients were included after excluding the patients with pure solid or cystic nodules or without further cytopathologic evaluation. We evaluated malignancy risk according to US features and changes in size and shape on follow-up US.
RESULTS
The malignancy rate was 31.6% (6 of 19) for nodules with suspicious US features and 2.7% (8 of 297) for nodules without suspicious US features (p<0.001). Among 265 nodules with no suspicious US features and initial benign cytology, 15 nodules with suspicious US change and decreased size, 25 nodules with no suspicious US change and increased size, and 225 nodules with no suspicious US change and no change in size were observed on follow-up USs. The malignancy risk thereof was 0%, 0% and 0.4%, respectively (p=1.000).
CONCLUSION
Mixed echoic nodules with no suspicious US features and benign cytology can be followed up using US, as they revealed very low malignancy rates, even if they showed growth on follow-up US.

Keyword

Mixed echoic thyroid nodules; fine needle aspiration biopsy; ultrasound

MeSH Terms

Adult
Biopsy, Fine-Needle/methods
Female
Humans
Male
Middle Aged
Thyroid Neoplasms/diagnosis/ultrasonography
Thyroid Nodule/*diagnosis/*ultrasonography

Figure

• 

  Fig. 1 Diagram of the study population. non-op, without operation; Op, with operation; FNA, fine needle aspiration.

• 

  Fig. 2 A 51-year-old woman with a thyroid nodule in the right thyroid on US. Initial FNAB revealed the nodule to be benign on cytology, and follow-up FNAB after 1.5 year showed the same cytologic result. (A) Initial US shows a mixed echoic nodule (>50% cystic) (arrows). (B) On follow-up US, this nodule showed decreased size and suspicious US changes including hypoechoic and microlobulated margins and taller-than wide shape (arrows). US, ultrasound; FNAB, fine needle aspiration biopsy.

• 

  Fig. 3 A 56-year-old woman with a thyroid nodule in the right thyroid on US. Initial FNAB revealed the nodule to be benign on cytology, and follow-up FNAB after 3 year showed the same cytologic result. (A) Initial US shows a mixed echoic nodule (< 50% cystic) (arrows). (B) On follow-up US, this nodule showed increased size without change in shape (arrows). US, ultrasound; FNAB, fine needle aspiration biopsy.

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