A 44 year-old female with a PLUMMER'S disease was reported. She complained of anteriot neck tumor, easy fatigability and weight loss etc. An elastic hard mass, 4 × 3 cm sized, was noted on the isthmus of the thyroid gland. The thyroid functional test presented a hyperthyroidism. The thyroid scintigram revealed a hot nodule on the same part of the thyroid gland. Surgical removal of the thyroid nodule was carried out and the thyroid function was slowly changing to an euthyroidism.