J Formos Med Assoc
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Failure of embryologic development of a lobe of the thyroid gland is a rare anomaly. We report a 47-year-old female with right thyroid hemiagenesis, papillary thyroid cancer, and an ectopic prelaryngeal thyroid rest. ⋯ During the operation, an isthmus and an enlarged left lobe with a cancer mass 2 cm in diameter were found, and a solitary piece of thyroid tissue about 0.7 cm in length was present just below the hyoid bone. We conclude that recognition of this rare anomaly by means of both scintigraphy and ultrasonography is valuable for a complete thyroidectomy, and for avoiding unnecessary contralateral dissection and damage.