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

Abstract

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.

Keywords: Hashimoto thyroiditis; fine needle aspirate; non-Hodgkin B-cell lymphomas; primary thyroid lymphoma; survival.

Figure 1

Diffuse large B-cell lymphoma (DLBCL) consisting of discohesive atypical lymphoid cells with (a) moderate pleomorphism, H&E staining; (b) tumor necrosis, H&E staining; and (c) lymphoepithelial lesions, H&E staining. Immunohistochemical positivity of tumor cells for (d) CD20. Original magnification ×400 (a) and ×200 (b–d).

Figure 2

Extranodal marginal zone lymphoma (E-MZL). (a) Tumor consisting of small, monomorphic lymphoid cells that replace the follicular architecture, H&E staining; (b) Lymphoepithelial lesions, H&E staining. Immunohistochemical positivity of tumor cells for (c) CD20 and (d) BCL2. Original magnification ×200 (a–d).

Figure 3

Follicular lymphoma. (a) Atypical lymphoid infiltrate is organized in the form of neoplastic follicles with irregular and enlarged germinal centers, H&E staining; (b) Lymphoepithelial lesions with a “ball-like” aspect, H&E staining. Immunohistochemical positivity of tumor cells for (c) CD20 and with limited (focal) positivity for (d) BCL2. Original magnification ×100 (a,c), ×200 (d) and ×400 (b).