[Thyroid hemiagenesis. Report of 3 cases and review of the literature].

The absence of one lobe of the thyroid gland is named thyroid hemiagenesis, the left is affected more frequently (80 percent), in the 50 percent is associate with isthmus agenesis. Predominant in the women, with relation 3:1, the oppose lobe may be of big size and in the 38-47 percent have alteration in the function, of which the hyperthyroidism is more frequently. In 1896 Handfield-Jones reported the first case, having in this moment 118 cases in the world literature, we reported three more, one of which is the second associated with hyperparathyroidism and other is the third with hypothyroidism. The diagnosis was made with I-131 thyroid gammogram and neck echosonography that which evidence the hemiagenesis, and was not necessary to realize the thyroid gammagram with thyroid stimulation hormone. In different series of surgery, necropsis or by thyroid illness the frequency of thyroid hemiagenesis is estimate below 1 percent.