Clinical presentation: A 31-year-old woman came to a follow-up visit. She has been treated for recurrent hyperthyroidism for more than 5 years. Previously we suggested definitive therapy but the patient refused our suggestion until this time. Now she had again complaints suggesting a relapse.

Palpation: Both lobes were enlarged. There were no palpable nodules.

Laboratory tests: TSH 0.001 mIU/L, FT4 51.2 pM/L on daily 15 mg methimazole.

Ultrasonography. The thyroid was hypoechogenic and had echonormal fields. There were hyperechogenic lines and granules corresponding to proliferation of connective tissue. The vascularization was increased.

Suggestion. The dose of methimazole was increased to 30 mg. The FT4 level became normal 6 weeks later and the patient accepted our suggestion to undergo on definitive therapy. She wished to be operated on instead of radioiodine treatment.

Histopathology: Diffuse goiter.