Hashimoto’s hyperthyroidism usually has mild and transient hyperthyroidism; thus, most patients in hyperthyroid state remain unrecognized. In this patient, the clinical manifestations and very high level of FT4 suggesting Graves’ hyperthyroidism; however, there was no TRAb results to confirm such a diagnosis. Nevertheless, in addition to high TSHs level, positive microsomal antibody and thyroglobulin antibody as well as the result of histopathological
examination have provided evidences for Hashimoto’s thyroiditis.