PSEUDOLYMPHOMA OF THE THYROID-GLAND - A CASE-REPORT

An unusual case of pseudolymphoma of the thyroid gland is presented. A well-demarcated whitish mass measuring 1.0 cm in diameter was found i n. the upper center of the right lobe of the thyroid gland. Microscopi cally, the lesion was composed of hyperplastic lymphoid tissues with m any follicular centers and mixed infiltration of plasma cells and macr ophages. The immunostain revealed a similar distribution of T- and B-l ymphocytes to reactive lymph node and a polyclonal nature of the plasm a cell infiltrates. No lymphoepithelial lesion was associated. The adj acent thyroid tissues showed chronic lymphocytic thyroiditis. This fin ding suggests that the lesion is a pseudolymphoma of the thyroid gland . This condition is rare, but it should be considered during the diffe rential diagnosis of lymphoproliferative lesions occurring in the thyr oid gland, especially with low-grade malignant lymphoma of the thyroid gland.