Clinical presentation: A 40-year-old woman was referred for aspiration cytology because of a nodule. The patient was treated for Graves' disease for more than 5 years. The hyperthyroidism has relapsed 5 months before present investigation. Actually, she had no complaints except for diplopia caused by TAO.

Palpation: Both lobes were enlarged but no nodule could be palpated.

Laboratory tests: TSH 0.23 mIU/L, FT4 24.6 pM/L on daily 20 mg methimazole therapy.

Ultrasonography. The thyroid was echonormal and presented hypoechogenic areas. The echogenicity index was around 20%. The minimally-moderately hypoechogenic lesions did not corresponded to nodule in a pathological sense, they had irregular borders and their shape was not of regular geometrical. There was a relatively large cystic area in the upper part of the left lobe.

Cytology was performed from the moderately hypoechogenic lesion in the lower-middle dorsal part of the left lobe and resulted in benign lesion.

Total thyroidectomy was performed. Histopathology disclosed diffuse goiter with signs of hyperfunction. There were no nodules.

Comments.

1. It is worth analyzing the shape and the borders of the lesions in the left lobe. These are typical of an autoimmune process and are frequently misinterpreted as nodules.

2. The relatively large cystic area in the left lobe proved to be a dilated follicle.