Clinical data: a 37-year-old woman was referred for an evaluation of hyperthyroidism. Hyperthyroid complaints lasted for 3 weeks. She had no signs of thyroid associated ophthalmopathy.

Palpation: thyroids were moderately firm and not tender.

Functional state: hyperthyroidism (TSH 0.001 mIU/L, FT4 49.1 pM/L, FT3 9.08 pM/L).

Ultrasonography: around 60% of the thyroid was composed of hypoechogenic areas with blurred borders and decreased blood flow. After ultrasonographic examination we asked a more detailed description from the patient about her complaints. She told that at the onset of her hyperthyroid complaints her neck was tender and subfebrility was observed.

Cytological diagnosis: consistent with subacute de Quervain's thyroiditis. Follicular cells, various inflammatory cells including epitheloid cells were found on the smear.

We indicated erythrocyte sedimentation rate, CRP, aTPO and TSH-receptor antibody test with 48 mm/H, 18.7 mg/L, 1 U/mL and negative results, respectively.

Combined clinical-ultrasonographic-cytological diagnosis: benign subacute, de Quervain's thyroiditis.

We administered beta-blocking agent.

Comments.

1. The extent of hyperthyroidism was in the usual range observed in Graves disease and much greater than in the case of de Quervain's thyroiditis.

2. The ultrasonographic picture is almost decisive, such pattern, i.e. hypoechogenic discrete areas with blurred borders and decreased vascularization, does not occur in the hyperthyroid phase of a Graves disease. Such pattern may be observed in clinically subacute form of lymphocytic thyroiditis but infrequently.