Hashimoto's thyroiditis presenting as a single toxic adenoma (A case report).

Background: Hashimoto's thyroiditis can be present with a localized palpable nodule though presentation as a hyperfunction "nodule" is extremely rare. The first case of Hashimoto's thyroiditis and hot nodule was reported in 1971 by Warner.

Methods: We reported a 26-year-old hypothyroid woman in Hashimoto's thyroiditis background with a hyperactive thyroid nodule in both 99mTc and I131scintigraphy. The nodule disappeared after eight months of sufficient thyroid hormone replacement therapy.

Conclusions: Toxic adenoma in hypothyroid patients can be resolved after levothyroxine (L-T4) replacement therapy.