Clinical presentation: A 37-yr-old woman was referred for evaluation of a multinodular goiter detected on examination performed because of infertility.

Palpation: no abnormality.

Laboratory tests: TSH 1.75 mIU/L, aTPO 126 U/mL.

Ultrasound. The thyroid was echonormal and presented numerous small, hypoechoic areas. The latter had spiculated margins. There was an echonormal nodule in the right lobe. This lesion presented two protrusions.

Aspiration cytology from the echonormal nodule resulted in Hashimoto's thyroiditis.

Comments.

1. The discrete lesions of Hashimoto's thyroiditis usually present spiculated margins.
   
2. An infiltration of an echonormal nodule by hypoechoic tissue of thyroiditis mimics lobulation. In such cases the pathological, infiltrative process is not the disease which caused the nodule but the underlying thyroiditis. Moreover, infiltration of an echonormal nodule by thyroiditis does not mean that a lesion with different echogenicities should be regarded as a heterogeneous nodule.