Clinical presentation: A 60-year-old woman was referred for evaluation of a hypothyroidism and nodular goiter have been known for a decade.

Palpation. No abnormality.

Laboratory tests: TSH 1.08 mIU/L, aTPO 92 U/mL on daily 87.5 microgram levothyroxine.

Ultrasonography. The thyroid was minimally-moderately hypoechogenic. There was a more inhomogeneous, more echogenic discrete area in the medial part of the right lobe. Compared with the first examination, the discrete lesion has increased by more than 60% in volume.

Aspiration cytology: Hashimoto's thyroiditis.

Comments.

1. It is ambiguous as to whether this lesion is a nodule in pathological sense or not.
   
2. The histogram value of the extranodular part of the right lobe is 23.6 while that of the discrete lesion is 31.6. It means that if the reference tissue is the non-nodular part than the lesion is hyperechoic. On the other hand, if we compare the echogenicity of the lesion to a healthy thyroid than this is a moderately hypoechoic lesion.