Primary malignant lymphomas of the thyroid. A brief review.

Primary lymphoma of the thyroid is a rare disease, occurring predominantly in elderly women but it is more and more reported in younger generation and this seems to reduce the female preponderance. Clinically it is characterized by a rapid and diffuse enlargement of the thyroid with hoarseness, dysphagia and local tenderness. There is a frequent coexistence of Hashimoto's thyroiditis with presence of autoantibodies. This latter disease has to be considered as a prelymphomatous condition. The differential diagnosis between the two is not always easy. The new functional classification of non hodgkin's lymphomas can be applied successfully in primary lymphomas of the thyroid: they allow to establish a prognosis and demonstrate that most of these lymphomas are B-cell derived and of follicular center cell origin. The diagnosis can be made by means of a biopsy and sometimes by fine needle aspiration.