Neck Dissection by Brendan C. Stack Jr. Mauricio A. Moreno

Author:Brendan C. Stack, Jr.,Mauricio A. Moreno
Language: eng
Format: epub
Publisher: Thieme Medical Publishing Inc.
Published: 2019-09-15T00:00:00+00:00

Fig. 14.3 Hashimoto's benign hyperechoic nodules (white knights).

Fig. 14.4 Hashimoto's large hypoechoic areas.

Fig. 14.5 Thyroid lymphoma.

Fig. 14.6 Spongiform nodule.

Fig. 14.7 Spongiform-appearing nodule positive for papillary thyroid carcinoma.

Fig. 14.8 Primary papillary thyroid carcinoma with microcalcifications.

It should be kept in mind that the presence of coarse calcification does not preclude the diagnosis of thyroid carcinoma, although usually, if malignant, they will be accompanied by microcalcifications ( Fig. 14.9). Hypoechogenicity is also a common finding in thyroid carcinoma.10 The degree of hypoechogenicity is highly variable, ranging from an almost completely black appearance similar to the echogenicity of the carotid artery ( Fig. 14.8) to nodules that are just barely darker than the surrounding thyroid tissue ( Fig. 14.10). The sensitivity of hypoechogenicity is very high, but the specificity is rather low. For example, benign nodules can also be very hypoechoic. The continuity of the capsule is very important. If there is blebbing of the nodule out into surrounding thyroid, or a very poorly defined capsule ( Fig. 14.9), this should be immediately concerning for the presence of malignancy.11 A nodule that is taller than it is wide has been shown to have a higher propensity for malignancy.11 The physiologic basis for this phenomenon is unclear, but it has been reported to have a specificity as high as 90%.12 Size alone is a relatively poor indicator of malignancy. Generally, there is a positive correlation between the size of a nodule and its risk of malignancy. This is particularly true for nodules that are 2 cm or greater in size.13 However, some studies have shown that nodules greater than 4 cm have a smaller chance of being malignant than nodules that are less than 4 cm.14 In addition, there was no increased risk of malignancy in follicular neoplasms greater than 4 cm in size.15 However, large nodules that are extremely hypoechoic, similar to that of the carotid artery, are highly suspicious and often are lymphoma ( Fig. 14.5) or poorly differentiated/anaplastic carcinoma ( Fig. 14.11).

Using the above criteria, there are some nodules that appear to be malignant immediately after the transducer is placed on the neck. However, this is not always the case. There are many instances where nodules are found to be malignant on FNAB with only mild hypoechogenicity on US ( Fig. 14.7).

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