Ultrasonography in the diagnosis of thyroid lymphoma

Lymphoma of the thyroid is a rare condition, classically occurring in elderly caucasian women, presenting as a rapidly enlarging, symptomatic mass. Almost all examples are due to non-Hodgkin's lymphoma, and the lesion is commonly superimposed on pre-existing Hashimoto's thyroiditis. Prognosis is best if the disease is diagnosed early and while confined to the thyroid region, there being a favourable response to radiotherapy alone. Unfortunately, lymphoma is rarely considered in the differential diagnosis of thyroid masses, often leading to unnecessary, excessive surgery. Ultrasonography of five patients was analysed to determine if any common diagnostic features were present. All had a similar pattern, with a large, circumscribed, solid hypoechoic mass. Although nonspecific, this appearance, with awareness of a rapidly growing mass, should alert the radiologist and attending clinician to the possibility of lymphoma.