Errors and mistakes in ultrasound diagnostics of the thyroid gland

Abstract

Ultrasound examination of the thyroid gland permits to evaluate its size, echogenicity, margins, and stroma. An abnormal ultrasound image of the thyroid, accompanied by other diagnostic investigations, facilitates therapeutic decision-making. The ultrasound image of a normal thyroid gland does not change substantially with patient's age. Nevertheless, erroneous impressions in thyroid imaging reports are sometimes encountered. These are due to diagnostic pitfalls which cannot be prevented by either the continuing development of the imaging equipment, or the growing experience and skill of the practitioners. Our article discusses the most common mistakes encountered in US diagnostics of the thyroid, the elimination of which should improve the quality of both the ultrasound examination itself and its interpretation. We have outlined errors resulting from a faulty examination technique, the similarity of the neighboring anatomical structures, and anomalies present in the proximity of the thyroid gland. We have also pointed out the reasons for inaccurate assessment of a thyroid lesion image, such as having no access to clinical data or not taking them into account, as well as faulty qualification for a fine needle aspiration biopsy. We have presented guidelines aimed at limiting the number of misdiagnoses in thyroid diseases, and provided sonograms exemplifying diagnostic mistakes.

Keywords: fine needle biopsy; medical mistakes; thyroid; thyroid diseases; ultrasound imaging.

Fig. 1

Sonogram shows a solitary, hypoechoic focal lesion 6 mm in diameter, found in the right thyroid lobe (arrow). Histopathology: follicular thyroid carcinoma

Fig. 2A, B

Sonogram shows the esophagus visible in a transverse section (arrow), mimicking a focal lesion located in the inferior pole. In the longitudinal section visible: layer structure of the esophagus, fluid and gas bubbles in the lumen

Fig. 3A, B

Gray scale sonogram shows a hypoechoic focal lesion occupying the left thyroid lobe (arrow, A). Color Doppler sonogram shows the inferior thyroid vein and the inferior thyroid artery (arrow, B)

Fig. 4

Sonogram shows parathyroid hypertrophy (white arrow) visible as a hypoechoic, well-defined lesion, situated below the inferior pole of the right thyroid lobe in a patient with chronic renal insufficiency. Additionally, the patient presented with esophagus located on the right side of the neck (red arrow)

Fig. 5

Sonogram shows an adenoma of the right parathyroid presenting as a solid, oval, hypoechoic lesion situated below the inferior pole of the right thyroid lobe (photo courtesy of professor RZ Słapa M.D. PhD)

Fig. 6

Sonogram shows hypoechoic, rounded cranial lymph nodes (arrows), with ill-defined capsule margins, and no visible hila, with metastatic involvement in a patient with papillary thyroid carcinoma

Fig. 7A

Sonogram shows metastatic lymph nodes (arrows) in a patient with papillary thyroid carcinoma. Noticeable hyperechoic sinuses with microcalcifications

Fig. 7B

Color Doppler sonogram shows papillary thyroid carcinoma, visible numerous tortuous vessels entering the lesion

Fig. 8

Sonogram shows an increased blood flow in the thyroid parenchyma in the course of hyperthyroidism

Fig. 9

Sonogram shows hyperthyroidism in the course of Graves’ disease: moderate enlargement of the thyroid gland, heterogeneous echogenicity, visible dilated blood vessels in the thyroid parenchyma (arrows). The image was erroneously interpreted as parenchymatous goiter

Fig. 10

Sonogram shows hypothyroidism: the thyroid small, decreased echogenicity, thyroid margins ill-defined, visible echoes from the stroma (arrows)

Fig. 11

Sonogram shows a typical image of lymphocytic thyroiditis: numerous hypoechoic infiltrates in the thyroid parenchyma

Fig. 12

Sonogram shows stumps of the thyroid lobes following thyroidectomy. Heterogeneous echogenicity of the stump parenchyma, numerous minor calcifications in the parenchyma (arrows)

Fig. 13

Sonogram shows a typical image of a thyroid cyst

Fig. 14

Sonogram shows small cystic nodules (CTN) in the thyroid parenchyma

Fig. 15

Sonogram shows a solid-cystic focal lesion with well-defined margins, with solitary peripheral vessels. Cytology: oncocytic tumor

Fig. 16

Sonogram shows a typical ultrasound image of the halo sign in a solitary thyroid nodule (A), and hyperplastic nodules in a multinodular goiter (B) (arrows)

Fig. 17A

Sonogram shows a hypoechoic focal lesion with micro- and macrocalcifications (arrow), warranted FNA biopsy, with a visible needle end in the lesion

Fig. 17B

Sonogram shows a solid hypoechoic lesion with well-defined margins, with micro- and macrocalcifications. Cytology: a hyperplastic nodule

Fig. 18

Sonogram shows a comet tail artifact (arrow) in a colloidal degeneration of a thyroid nodule