[Spontaneous hypothyroidism in 4 patients with Graves-Basedow disease]

We present 4 patients with Graves' disease who developed spontaneous hypothyroidism during follow-up. The two most plausible physiopathologic mechanisms for this development were progressive autoimmune-mediated destruction of the thyroid follicular epithelium and a predominance of blocking antibodies to the thyroid-stimulating hormone (TSH) receptor at the expense of stimulating antibodies in the same patient. Description of these patients not only illustrates the heterogeneous nature of this disease, but also the interrelation among its distinct clinical forms.