Left lobe hypoplasia of thyroid with right lobe ectopia: Radionuclide thyroid scan and ultrasonographic correlation.

Sir,

Developmental anomalies of the thyroid are rare. They are usually a result of abnormal descent rather than of abnormal development.[12] Unilateral or bilateral hypoplasia or agenesis of one or both thyroid lobes, with or without ecopia, is a rare developmental anomaly.[3] Only a few cases have been reported in the world literature. Thyroid function may be altered in 38–47% of patients.[45] Thyroid scan and ultrasonography play an important role in diagnosis.[67]

We report a case of right lobe ectopic thyroid in a 20-year-old female with the hypoplastic left lobe of thyroid gland. The patient presented with a midline swelling at the base of tongue with dysphagia. Thyroid function test revealed subclinical hypothyroidism. A thyroid scan with technetium-99m pertechnate showed only right lobe of thyroid located slightly more superior to the eutopic position. No uptake was seen in the thyroid lobe on the left side [Figure 1]. Ultrasonography of the neck showed hypoplastic left lobe of thyroid [Figure 2a and b].

Figure 1

Thyroid scan showing the right lobe of thyroid gland as pyramidal in shape with the superior pole directed toward hyoid bone. Tracer distribution is mildly increased and homogenous in this lobe. No dominant hot or cold nodule noted. No significant tracer uptake noted in the left lobe of thyroid

Figure 2

(a) Ultrasonographic images of thyroid showing right lobe of thyroid as lying at a slightly superior location compared to the left side. (b) Left lobe of thyroid is small in size and normal in echotexture

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