J Korean Radiol Soc.  1998 Mar;38(3):431-435. 10.3348/jkrs.1998.38.3.431.

Ectopic Thyroid Glands: Clinical and Radiological Features

• Cho N
• Yoon CS
• Oh SJ
• Chung TS
• Kim MJ
• Kim DI
• Lee JD
• Park MS

• KMID: 2201397
• DOI: http://doi.org/10.3348/jkrs.1998.38.3.431

Abstract

PURPOSE: To understand the various clinical and radiological features of ectopic thyroid.
MATERIALS AND METHODS
This study involved nine ectopic thyroid cases (M:F=2:7; age range, 2-57 years) confirmed by RI thyroidscan between 1993 and 1997. We analyzed one neck ultrasonogram, five CT scans, three MR images, nine Tc-99mthyroid scans, and classified the ectopic thyroid by the basis of these findings. Hormonal abnormalities andsymptoms were evaluated on the basis of medical records.
RESULTS
The status of nine patients was found to beeuthyroid (n=6), hypothyroid (n=2) or hyperthyroid (n=1). Among the nine, the ectopic thyroid was lingual (n=6),sublingual (n=3) or thyroglossal (n=1); one patient had both the lingual and sublingual types. Ectopic thyroid wasseen as a well-defined round mass, homogeneously enhanced on CT scan, homogeneously hyperechogenic onultrasonogram and of intermediate signal intense on MRI. All cases showed ectopic radioactivity uptake on Tc-99mthyroid scan. In eight patients, ectopic thyroid was the only hormone-producing thyroid tissue; one had bothnormal thyroid and ectopic thyroid tissue in a thyroglossal duct cyst. Among the six cases of euthyroidism,ectopic thyroid patients with the lingual type complained of throat discomfort. Those with the sublingual typecomplained of palpable neck mass, and preoperative evaluation of thyroglossal duct cyst showed that this wasectopic thyroid.
CONCLUSION
Understanding the various clinical and radiologic features of ectopic thyroid canhelp accurate diagnosis and prevent unnecessary surgery or other procedure.

Keyword

Thyroid, abnormalities

MeSH Terms

Diagnosis
Humans
Magnetic Resonance Imaging
Medical Records
Neck
Pharynx
Radioactivity
Thyroglossal Cyst
Thyroid Dysgenesis*
Thyroid Gland
Tomography, X-Ray Computed
Ultrasonography
Unnecessary Procedures

Figure

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  Fig. 1. 52-year-old man with neck mass Tc-99m thyroid scan shows smaller right thyroid in normal position with mild radioactivity uptake in above the isthmic portion of normal thyroid.

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  Fig. 2. 7-year-old girl with neck mass A. Ultrasonogram shows a well defined hyperechoic homogeneous mass (arrows) at sublingual site. B. Contrast enhanced CT scan shows a well defined oval shape mass in this site. C. Tc-99m thyroid scan shows radioactivity uptake at sublingual site and absence of uptake in normal thyroid position.

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  Fig. 3. 35-year-old woman with throat discomfort A. Contrast enhanced CT scan shows a well enhanced round mass at tongue base. B. The signal intensity of the mass is slightly higher than that of tongue muscle on Tl weighted MR image. C. The signal intensity of the mass is slightly higher than that of tongue muscle on T2 weighted MR image. D. Gadolinium-enhanced Tl weighted MR image shows mild peripheral enhancement of the mass.

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  Fig. 4. 12-year-old girl with neck mass A and B. Contrast enhanced CT scans show a well enhanced mass at tongue base (A) and another well enhanced mass at left submental area(B). C. Tc-99m thyroid scan shows two separate foci of radioactivity. Note absence of uptake in lower neck.

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