Right hemiagenesis thyroid with Hashimoto's thyroiditis, ultrasound study

A case of Hashimoto's thyroiditis. On thyroxine therapy. 

However, sonography shows congenital absence of the right lobe of thyroid. 

Power Doppler ultrasound shows hypervascular left lobe. 

Final diagnosis:

Hashimoto's thyroiditis with right hemiagenesis.