[Differentiated thyroid carcinomas manifesting as toxic adenoma].

Background: Hot thyroid nodules are generally benign. We report two exceptional cases of thyroid carcinomas mimicking toxic adenomas.

Case Reports: A 35-year-old man and a 55-year-old woman had thyroid carcinoma behaving as an autonomously hyperfunctioning nodule.

Discussion: Only twenty similar cases have been reported in the literature. While a hot nodule on radio-iodine scan is unlikely to be malignant, the possibility of carcinoma should not be overlooked. Surgery should therefore be the preferred treatment of toxic adenoma.