Ectopic thyroid tissue in the neck. Benign or malignant?

This is a report of ectopic thyroid tissue in the neck, associated with a nodular colloid goiter, which recurred at least three times, beginning at age 24 years, in a woman in 12 years. The ectopic tissue appeared histologically benign and was identical to that found in the thyroid gland. Scintiscans of the neck and thyroid suppression tests showed that the tissue was initially unsuppressible and presumably autonomous in its function. Our conclusion is that the most reasonable explanation for this phenomenon is the intraoperative transmission of thyroid cells, probably benign and autonomous in function, to other sites in the neck.