A solitary minute thyroid lymphoma of MALT-type without lymphoid thyroiditis.

Most of the primary thyroid malignant lymphomas have been considered of mucosa-associated lymphoid tissue (MALT) type and arise from lymphocytic thyroiditis. We report an uncommon case of a 67-yr-old man who underwent total thyroidectomy for multinodular goiter with tracheal compression. At histopathologic examination, we discovered a minute (3-mm diameter) lesion of low-grade thyroid lymphoma of MALT type without any lymphocytic thyroiditis lesion on 33 section levels of the entire thyroid gland. No general inflammatory, autoimmune, or lymphomatous disorder has been evidenced both at staging and after 30 mo of follow-up. MALT-type low-grade lymphoma may, in some instances, develop de novo within the thyroid without an antecedent MALT-type lymphoma.