The scintigraphic findings in Hashimoto's
thyroiditis are highly variable and can mimic any thyroid abnormality. In this study, we compared the scintigraphic findings with ultrasonography in 48 patients with Hashimoto's
thyroiditis. Thyroid scintigrams revealed diffuse
hyperplasia in 12 patients, multinodular
goiter in 20 patients and a solitary nodule in 16 patients (toxic
adenoma, n = 1; hypoactive nodule, n = 4; hyperactive nodule with no suppression, n = 3; normoactive nodule, n = 8). Ultrasonography revealed diffuse
hyperplasia in 19 patients, multinodular
goiter in 20 patients and a solitary nodule in 9 patients. The thyroid scan and ultrasonography revealed the same findings of diffuse
hyperplasia in 12 patients and multinodular
goiter in 20 patients. Of the 16 patients with a solitary nodule on scintigraphy, only 9 showed the same finding on ultrasonography, with the other 7 showing diffuse
hyperplasia. The difference in nodularity between thyroid scanning (74.9%) and sonography (60.4%) has been attributed to pseudonodularity in Hashimoto's
thyroiditis. In conclusion, our results confirmed that Hashimoto's
thyroiditis can mimic any thyroid abnormality, including diffuse
hyperplasia,
nodular goiter and multinodular
goiter on scintigraphy. Therefore, scintigraphy, ultrasonography and serum
thyroid hormone estimation alone may not be helpful for the final diagnosis of
Hashimoto's disease. To eliminate unnecessary surgical intervention, all patients should be evaluated by means of physical examination and thyroid
autoantibodies, in addition to a thyroid scan, ultrasonography, serum
thyroid hormones and fine-needle aspiration biopsy when necessary.