[Basedow-Graves disease development in 2 patients with primary hypothyroidism: exceptional development of the autoimmune thyroid disease].

Autoimmune thyroid disease has multiple manifestations and its presentation may change with time. We report two patients with primary hypothyroidism due to Hashimoto's disease that unexpectedly, developed a hyperthyroidism due to Basedow-Graves disease. This phenomenon may be explained by variations in the types and proportions of anti TSH receptor antibodies, that can stimulate or block thyroid gland function and growth. It is deducted that the hypothyroidism of these patients was not due to a definitive gland destruction, but to the action of function blocking antibodies.