This female patient presented with a one year history of hypothyroidism. A thyroid ultrasound showed the gland to be at the lower limit of normal size, have markedly coarsened echotexture and apparent thin internal septations. The vascularity was normal.
Hashimoto’s thyroiditis (chronic lymphocytic thyroiditis) is an autoimmune disorder often associated with hypothyroidism. The typical presentation is with painless enlarged thyroid. The typical ultrasound appearance is of diffusely coarse echotexture and reduced echogenicity. The gland is enlarged in most cases, at least at first. Multiple tiny hypoechoic nodules may be present (micronodulation) and are relatively specific if present. Linear echogenic septations may be present. The vascularity is typically normal or decreased. Cervical lymphadenopathy is often present. The thyroid gland later atrophies, and is small and heterogeneous.
Chronic lymphocytic thyroiditis may require fine needle biopsy for definitive diagnosis. There is an associated increased risk of thyroid lymphoma.
Differential diagnoses include: previous radiotherapy; Riedel’s struma; scleroderma; or infiltration of the thyroid (haemochromatosis, amyloidosis or sarcoidosis).
Reference: Rumack CM, Wilson SR, Charboneau JW. Diagnostic Ultrasound 3rd edition. Elsevier Mosby 2005.
Credit: Dr Laughlin Dawes