First examination (first and second rows of images):

Clinical presentation: A 41-year-old woman was referred for an evaluation of complaints suggesting hyperthyroidism.

Palpation: Both thyroids were enlarged and moderately firm.

Results of blood tests: hyperthyroidism (TSH undetectable, FT4 51.8 pM/L). 

Ultrasonography. A diffusely hypoechogenic thyroid was found with multiple lesions. There was a hypoechogenic lesion in the dorsal part of the right lobe. This lesion showed taller-than-wide and longer-than-wide shape. The left lobe had two lesions which were more echogenic than the non-nodular part of the lobe, however less echogenic than a normal, healthy thyroid. 

Cytology was performed from the hypoechogenic nodule found in the right thyroid and from one of the hyperechogenic nodules in the left lobe. Cytological diagnosis: benign pattern corresponding to hyperthyroidism.

TSAb was elevated 11.0 U/mL (normal value below 1.5) while scintigraphy excluded the possibility of autonomy.

Thyrostatic therapy was started. We told the patient that the final solution could be surgery.

Follow-up investigation 6 months after first visit (third row of images):

Clinical presentation. The patient refused our suggestion and went on conservative therapy. She had no complaints.

Palpation: unchanged.

Results of blood tests: euthyroidism on daily 5 mg methimazole (TSH 1.17 mIU/L, FT4 17.2 pM/L). 

Ultrasonography. Except for a minimal decrease in hypoechogenicity and in the vascularization the pattern was unchanged.

TSAb was already elevated 8.7 U/mL (normal value below 1.5).

Follow-up investigation 11 months after the initial one (fourth row of images):

Clinical presentation. The original complaints of the patient recurred including 3 kg loss in weight and tachycardia.

Palpation: unchanged.

Results of blood tests: hyperthyroidism (TSH undetectable, FT4 47.5 pM/L) on daily 10 mg methimazole. 

Ultrasonography. The degree of hypoechogenicity and vascularization increased compared with previous investigation.

The dose of the methimazole was increased to 20 mg.

Follow-up examination two years after the first visit (fifth row of images):

Clinical presentation. Due to her familiar circumstances, the patient was unable to undertake surgery.

Palpation: unchanged.

Results of blood tests: TSH 2.23 mIU/l, FT4 14,0 pM/l on daily 15 mg methimazole. 

Ultrasonography. The echogenicity of the non-nodular parenchyma became less hypoechoic compared with the previous examinations.

The dose of the methimazole was decreased to daily 10 mg.

Follow-up examination four years after the first visit (sixth row of images):

Clinical presentation. The patient had no complaints.

Palpation: no abnormality.

Result of blood test: TSH 0.01 mIU/l, FT4 16,7 pM/l on daily 10 mg methimazole.

Ultrasonography. The echogenicity of the non-nodular parenchyma returned to normal.

Follow-up examination six years after the first visit (seventh row of images):

Clinical presentation. Nine months after the previous visit, the hyperthyroidism has recurred again, the FT4 level was 49.4 pM/L at that time. Atrial fibrillation has developed. The dose of the thyrostatic was increased. The hyperthyroidism has gradually eliminated.

Palpation: no abnormality.

Result of blood test: TSH 0.01 mIU/l, FT4 16,7 pM/l on daily 10 mg methimazole.

Ultrasonography. The echogenicity was normal. The echogenicity of the nodule in the upper part of the left lobe became hypoechoic.

Suggestion: surgery

A total thyroidectomy was performed. Histopathology disclosed diffuse goiter in both lobes and benign hyperplastic nodules in the left lobe.

Comments. Several lessons can be learned from this case study.

1. It is worth analyzing the echo pattern of the thyroid. The small hypoechogenic area in the right lobe changed neither in size nor is shape nor in vascularization over 6 years.
   
2. The echo pattern of the thyroid was more hypoechoic in hyperthyroid states while has normalized when the patient became euthyroid.
   
3. The echogenicity of the nodule in the left lobe has been changed. At the first four examinations, it was more echogenic compared with the extranodular parenchyma while at the least visit, it became moderately hypoechoic.