High incidence of mucosa-associated lymphoid tissue in primary thyroid lymphoma: a clinicopathologic study of 18 cases in the Korean population.

The present study aimed to evaluate the clinicopathologic features and treatment outcomes of patients with primary thyroid lymphoma (PTL). The patients included 14 women and four men with a median age of 50 years (range 31 - 82 years). Thirteen cases involved the thyroid alone (stage IE) and five cases involved the regional lymph nodes (stage IIE). Histopathologic studies revealed marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) in 13 patients and diffuse large B-cell lymphoma (DLBCL) in three patients. The other two patients showed features of both MALT and DLBCL. Surgery and chemotherapy with or without radiotherapy were performed. All patients achieved complete remission. All 18 patients were alive with a median follow-up period of 55 months. The prognosis of patients with primary thyroid lymphoma appears to be favourable.