Clinical presentation: A 41-year-old woman requested a second opinion. She has been treated for hyperthyroidism for 8 months. Six weeks after initiation of thyrostatic therapy the thyroid hormone levels have normalized. One month prior to the present examination her complaints have recurred, among others diplopia has developed.

Palpation: no abnormality.

Laboratory investigation: TSH 0.01 mIU/L, FT4 39.4 pM/L, TSAb 5.2 U/L (normal value < 1.5).

Ultrasonography. The thyroid was echonormal and presented moderately hypoechogenic areas. None of them corresponded to a nodule in pathological sense. The vascularization was moderately increased.

Suggestion. Considering the TAO and the recurrence of hyperthyroidism, surgery was advised.

Histopathology: Diffuse goiter.