What is chronic lymphocytic thyroiditis (Hashimoto’s thyroiditis) ?
This is the most common diffuse thyroid disease. It affects as many as 5% to 10% of the adult population, with a strong female predominance, and is the most common cause of hypothyroidism in children and adults. This autoimmune thyroid disease is pathologically characterized by a lymphocytic infiltrate and glandular fibrosis. The thyroid gland may have a variety of appearances ranging from patchy, ill-defined, or geographic, hypoechoic regions superimposed on a normal background parenchyma to a diffusely hypoechoic gland with scattered linear echogenicities and an irregular capsule reflecting intraglandular fibrosis. The gland is usually enlarged, less commonly normal or small in size, and may have either increased or decreased vascularity depending on the degree of disease activity.