PRIMARY PLASMACYTOMA OF THE THYROID - A CASE-REPORT AND COMPARATIVE LITERATURE STUDY BETWEEN WESTERN NATIONS AND JAPAN

A 52 year old man presented with primary thyroid plasmacytoma. The pat ient was initially followed up for thyroid dysfunction. The histologic al examination of the removed thyroid revealed a proliferation of matu re and immature plasma cells indicative of plasmacytoma with Hashimoto 's disease. After radiotherapy (40 Gy) to the neck following right hem i-thyroidectomy, the patient is currently alive and well 3 years after diagnosis without any evidence of tumor. The immunohistological exami nation of the removed thyroid showed monoclonality for immunoglobulin G-Kappa light chains. Sixty-six literature cases of primary thyroid pl asmacytoma were reviewed and comparison of the clinical and histologic al characteristics between Japanese and Western cases noted. The incid ence of the patients with antithyroid antibody was significantly lower (P < 0.01) in Western patients (42.9%) than in Japanese patients (87. 5%). The higher incidence of thyroid dysfunction and Hashimoto's disea se in Japan in comparison with Western nations was well reflected in t he incidence of antithyroid antibody.