Lymphoma of the Thyroid Gland

At one time, primary (non-Hodgkin’s) lymphoma of the thyroid gland was considered to be a rare thyroid malignancy. However, in recent years it has been estimated that it may account for 5% to 10% of thyroid cancers. Among patients with a solitary discrete nodule of the thyroid gland, the incidence of primary lymphoma is 1 in 1000. In patients with diffuse goiters, the incidence of primary lymphoma is 1 in 100. Primary lymphomas of the thyroid land are said to constitute only 1.3% to 6.5% of all extranodal lymphomas. The reported mean age at the time of diagnosis is approximately 60 to 65 years with a range of 10 years to 90 years. The female-to-male ratio ranges from 3:1 to 18:1 but in the subgroup aged 60 years or less the ratio narrows toward 1:1. Approximately 40% of patients are under the age of 60 years at the time of diagnosis.1–18