Utility of Computed Tomography in Identifying an Ectopic Thyroid in Infants and Pre-school Children

Abstract

Abstract. In purpose of identifying thyroid tissue in patients with congenital hypothyroidism during childhood, ultrasonography is usually used as a screening examination, and scintigraphy is performed secondarily. Though these methods are useful, it is not easy to identify the accurate location of thyroid tissue by these methods. We previously reported the utility of computed tomography (CT) in identifying thyroid tissue in four cases of congenital hypothyroidism. The purpose of this study is to investigate whether CT is useful in identifying thyroid tissue, compared to ultrasonography or scintigraphy. Nineteen cases (0 month to 18 years of age) that were suspected to have ectopic thyroid tissue or thyroid agenesis on ultrasonography were examined by CT. CT was useful in diagnosing ectopic thyroid tissue or thyroid agenesis in all the cases, whereas ultrasonography or scintigraphy was less accurate in this purpose in seven cases. Plain CT had a difficulty in identifying thyroid tissue in two cases, in which contrasted image was required. This study showed that CT, especially an enhanced CT, is useful in identifying thyroid tissue, when the gland is not identified in the normal position by ultrasonography.

Ectopic thyroid tissue: anatomical, clinical, and surgical implications of a rare entity

“…In cases of cervical lymphadenopathy or intratracheal invasion by the tumor, CT and MRI may assist as the suspicion for malignancy is increased (17,34,73,76). Regarding CT imaging, thyroid tissue displays higher density on plain CT than the surrounding soft tissues, although enhanced images identify thyroid tissue more clearly than plain ones (17,76). In MRI, ectopic thyroid appears as a rounded mass with higher signal intensity than that of the surrounding tissue in both the T1-and T2-weighed images (73).…”

“…In some ectopies, other diagnostic tools, such as the endoscopic evaluation of intratracheal thyroid, are valuable. In these cases, ectopic thyroid usually presents as a smooth reddish-brown submucosal mass in a subglottic posterolateral position (32,76).…”

Ectopic Intrapulmonary Thyroid Tissue Mimicking Metastatic Tissue

“…However, the three tiny nodules showed the same CT findings as the biopsy-proven largest nodule in the right lower lobe; meaning that they had a higher density than the surrounding soft tissues due to their high concentration of iodine (11,12). In addition, the sizes of those nodules did not increase during the 6-month follow-up period.…”

Lateral pediatric ectopic thyroid

“…Preoperative thyroid scan is very useful in patients thought to have ectopic thyroid tissue; however, it is not accurate enough for location and operative planning purposes 2. Instead, contrast‐enhanced CT of the neck provides an excellent tool for locating ectopic thyroid tissue 3. CT provides a clear image for operative planning and has the added benefit of being a relatively quick study that is less likely to require sedation in a pediatric population.…”