TH and thyrotoxicosis: Indeed, we found the presence of TH in two non-GD cases with TgAb and TPOAb positivity, and negative TRAb: one case of silent thyroiditis, similar to the only other case report to date by Torres Gomez and Garcia Gastro [35]; instead, to the best of our knowledge, for the first time, we showed the case of a patient with thyrotoxicosis secondary to T4 + T3 therapy, where TH disappeared after switching to T4 monotherapy and achievement of biochemical euthyroidism.