A Rare Case of MALT Lymphoma With Hashimoto’s Thyroiditis: Differential Diagnosis of Cold Nodules on Tc-99m Pertechnetate Thyroid Scan

Abstract

MALT lymphoma of the thyroid is uncommon, comprising approximately 4% of all extranodal MALT lymphomas and commonly arises in a setting of Hashimoto thyroiditis. A 57-yearold female with Hashimoto thyroiditis was studied with Tc-99m pertechnetate thyroid scan to evaluate thyroid function. Radionuclide thyroid scan with Tc-99m pertechnetate revealed a medium sized, cold nodule in the enlarged left thyroid lobe. Preoperative contrast enhanced CT of the neck revealed a large focal area with less enhancing in the same area. The histologic examination was reported to be a lymphoproliferative lesion, extranodal marginal zone B-cell lymphoma (MALT lymphoma) with Hashimoto thyroiditis. A cold nodule of the thyroid gland is a nonspecific finding, and the possibility of MALT lymphoma should be considered. Key Words: MALT lymphoma, Hashimoto thyroiditis, cold nodule, Tc-99m O4