Lymphoma of the thyroid and head and neck.

The most common sites for extra-nodal lymphoma of the head and neck are Waldeyer's ring, most frequently the tonsil, and the salivary glands, usually the parotid. Most are B-cell malignancies and stage IE or IIE at diagnosis. Marginal zone lymphoma of mucosa-associated lymphoid tissue type is particularly associated with inflammatory conditions in the thyroid and salivary glands. The management of extra-nodal lymphoma in the head and neck is similar to nodal B-cell lymphoma with R-CHOP chemotherapy followed by radiotherapy, recommended for early-stage high-grade disease, and radiotherapy alone for localised low-grade lymphoma. The notable exception is NK/T-cell lymphoma of nasal type where radiotherapy is critically important and recommended to a higher dose, partly because of poor response to anthracycline-based chemotherapy regimens like CHOP. Given the higher doses required and the proximity of critical normal structures, intensity-modulated radiotherapy should be considered for these tumours.