Disparity of ultrasonography relevance in overt versus subclinical hypothyroidism

Purpose. The assessment of thyroid ultrasonography in hypothyroidism.Methods. We studied 421 cases of overt hypothyroidism and 1845 cases of subclinical hypothyroidism. All patients were screened for thyroid antibodies and underwent an ultrasonographic thyroid examination. Results. Ultrasonography was useful for the assessment of non palpable nodules. Nine patients with subclinical hypothyroidism had cancer: 4/9 patients had a non palpable cancer. Ultrasonography first displayed suspicious aspects in six patients. Two patients with overt hypothyroidism showed a palpable cancer with initially ultrasonographic suspicious aspects.Ultrasonography facilitated the study of thyroid biometry. Particularly, atrophy was encountered in almost one third of cases in the two types of hypothyroidism. Ultrasonography led to improved diagnosis of autoimmune thyroiditis from 92 to 98 percent of cases in overt hypothyroidism and from 70 to 79 percent of cases in subclinical hypothyroidism. Conclusion. The primary relevance of thyroid ultrasonography was the screening of some non palpable cancers in subclinical hypothyroidism. The secondary relevance was the improvement in the etiologic diagnosis of hypothyroidism, more often in subclinical hypothyroidism, and the follow-up of thyroid enlargement and initially non suspicious nodules.