RESUMO
PURPOSE: The purpose of this study was to determine the incidence, clinical and histologic features, and patterns of outcome of thyroid lymphomas. PATIENTS AND METHODS: A retrospective population-based survey of 38 patients with thyroid lymphoma was taken. Median age was 69 years (range, 33-87 years), with a 1:4 female predominance. Fifty percent of cases had a history of autoimmune thyroiditis, and coexistent thyroiditis was found in 67% of cases in which preexistent thyroid tissue was present. The most common subtype was diffuse large B-cell lymphoma (DLBCL; 63%) followed by extranodal marginal zone lymphoma (ENMZL; 29%). Ten of the patients with DLBCL showed a concomitant low-grade mucosa-associated lymphatic tissue component, and 4 cases of aggressive ENMZL were diagnosed. At diagnosis, 22 patients (58%) had localized disease, and 41% had low-risk international prognostic index scores. RESULTS: Therapy was diverse and included all possible treatment modalities, none of which showed superiority. A complete clinical response was exhibited in 64% of patients, 14% exhibited a partial response, and 22% developed progressive disease. At a median follow-up of 43 months (range, 0-240 months), 15 patients had relapsed or developed progressive disease. Two-year overall survival rate was 59% for all patients, 68% for patients with localized disease, and 47% for patients with disseminated lymphoma. CONCLUSION: Many thyroid lymphomas have clinical and histologic features characteristic of ENMZL and belong to this specific clinicopathologic entity.