Thyroid lymphoma with adjacent nerve paralysis.

Although local nerve invasion in thyroid lesions is most commonly found with anaplastic carcinoma, it does not rule out lymphoma. Open biopsy is most helpful in the diagnosis of lymphomas. Ultrastructural studies are often necessary for confirmation of the diagnosis. Differentiation between lymphoma and anaplastic carcinoma of the thyroid is very important since the treatment is substantially different and the prognosis is much better with lymphoma. To our knowledge, the case presented represents the first case of Horner's syndrome secondary to lymphoma that has been documented in the literature.