Primary Thyroid Lymphoma: A Retrospective-Observational Study in a Single Institutional Center.

Background and Objectives : primary thyroid lymphoma (PTL) is a rare neoplasm, displaying a variety of histological features. It is often a challenge for pathologists to diagnose this tumor. Materials and Methods : this study is a retrospective analysis of clinical and pathological characteristics of a group of eleven patients (eight women and three men, mean age 68 years, range 50-80 years) diagnosed with PTL. Results : nine patients (81.81%) presented a tumor with progressive growth in the anterior cervical region, usually painless and accompanied by local compressive signs. Histologically, we identified six cases (55%) of diffuse large B-cell lymphoma, three cases (27%) of extranodal marginal zone lymphoma, one case (9%) of follicular lymphoma, and one case (9%) of mixed follicular-diffuse lymphoma. PTL was associated with microscopic Hashimoto autoimmune thyroiditis in ten cases (90.9%). Ten patients (90.9%) presented with localized disease (stage I-IIE). A percentage of 60% of patients survived over 5 years. We observed an overall longer survival in patients under 70 years of age. Conclusions : PTL represents a diagnosis that needs to be taken into account, especially in women with a history of Hashimoto autoimmune thyroiditis, presenting a cervical tumor with progressive growth. PTL is a lymphoid neoplasia with favorable outcome, with relatively long survival if it is diagnosed at younger ages.