Lingual Thyroid

An Ectopic Presentation at the Base of the Tongue

Abstract

Lingual thyroid is the most common form of thyroid ectopia, resulting from failure of normal caudal migration of the thyroid anlage during embryogenesis.1 Diagnosis relies on cross-sectional imaging to define anatomy and radionuclide scintigraphy as the gold standard to verify functional thyroid tissue and exclude normally located gland.2

The images depict the clinical, radiological, and scintigraphic findings of a 27-year-old woman with ectopic lingual thyroid. Clinical photograph showed a smooth, reddish, round mass at the tongue base (Figure 1). Contrast-enhanced CT in sagittal and axial views demonstrated an enhancing lesion at the posterior tongue with the absence of orthotopic thyroid tissue in the pretracheal area (Figure 2). Tc-99m pertechnetate scintigraphy showed focal tracer uptake in the lingual region (Figure 3), confirming the diagnosis of ectopic thyroid tissue.