[Thyroid hemiagenesis associated with Basedow-Graves disease. Report of a case].

We report a 35 years old female with left lobe thyroid hemiagenesis who initially was euthyroid and then developed hyperthyroidism due to Graves disease. Hemiagenesis of the thyroid gland is a rare anomaly with an uncertain incidence; up to now 256 cases have been reported. The detection is often made by either clinical symptoms of thyroid dysfunction, by imaginological studies or surgical/pathological procedures. No explanation has been given for the development of this anomaly; left lobe aplasia and predominance of occurrence in women have been most frequently reported.