Clinical presentation: A 60-year-old woman was referred for aspiration cytology. She has been treated for relapsing hyperthyroidism for 3 years. Scintigraphy disclosed a uniform uptake while a large nodule was found on ultrasound.

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

Laboratory tests: TSH 0.001 mIU/L, FT4 22.9 pM/L, FT3 4.10 pM/L, TSAb negative, aTPO 22 U/mL on daily 15 mg methimazole.

Ultrasonography. The thyroid was echonormal. There were several discrete lesions of different echogenicities. The largest one was located in the right lobe and in the isthmus. The vascularization was not specific.

Cytology resulted in benign colloid goiter.

Histopathology: Diffuse goiter without any nodules.

Comments.

1. At first sight it is hard to believe on ultrasound pattern that this patient had no nodules. On the other hand, it is worth taking into account several facts. Fist, the patient had a uniform uptake on scintigraphy, it means that autonomy could be excluded as a cause for hyperthyroidism. Second, the aTPO level was a bit increased. Most of the discrete lesions had either non-geometrical shape or blurred borders. The presentation of the large lesion in the right lobe is very similar to that not infrequently seen in Hashimoto's thyroiditis: a central hypoechogenic area is surrounded with an echonormal rim which mimics a large hypoechogenic nodule.

2. Nevertheless, this is an exceptional case. Such ultrasound presentation in most cases corresponds to nodular goiters.