Identification of primary thyroid lymphoma with medical imaging: A case report and review of the literature

A diffuse large B-cell thyroid lymphoma presented as a compressive goiter in a young woman with no evidence of Hashimoto's thyroiditis

Thyroid lymphoma should be suspected in case of rapid enlargement of the thyroid gland even in a young patient with no history of Hashimoto thyroiditis. The confirmation is based on histopathology and immunohistochemistry.

Lymphomas and thyroid: Bridging the gap

The thyroid gland is often involved in the development of neoplastic diseases, including lymphoproliferative disorders. The aim of this paper is to provide a comprehensive overview of the multiple interactions between lymphoma and thyroid. Through an extensive research among the literature, the relationship between lymphomas and thyroid can be established at various levels, and the possible interconnections are here summarized in 5 points: (1) the greater risk of lymphoma development in some thyroid diseases; (2) the primary thyroid lymphoma, with focus on issues related to the diagnosis, differential diagnosis, and treatment; (3) the incidence of thyroid involvement in primitive nodal lymphomas or in extranodal lymphomas of the other sites; (4) thyroid changes after treatment of lymphoma, in relation to the effects of radiation therapy and immuno-chemotherapy; (5) the incidental findings of thyroid changes, on imaging, in patients with lymphoma, without a direct involvement of the gland in malignant disease. In conclusion, issues that until now have been dealt with separately will therefore be analyzed in a unique paper, allowing a global view of the topic and emphasizing the need of a multidisciplinary approach. Future learning areas in this topic mainly relate to rapidly increasing the knowledge of imaging studies together with expanding the armamentarium of novel biological and targeting agents in lymphoma patients.

Comparison of sonographic characteristics of primary thyroid lymphoma and anaplastic thyroid carcinoma

BACKGROUND

Although primary thyroid lymphoma (PTL) and anaplastic thyroid carcinoma (ATC) both account for a rare portion of the morbidity of all thyroid malignancies, the therapeutic methods and prognosis for these two diseases are different. The purpose of this study was to investigate the sonographic characteristics of PTL and ATC and to compare the sonographic findings of PTL and ATC.

METHODS

The study included 42 patients with histopathologically proven PTL (n=27) and ATC (n=15). The Clinical characteristics and sonographic findings were retrospectively reviewed and compared between the two groups.

RESULTS

The mean age of patients with ATC was not significantly different from that in patients with PTL (P=0.601). The female-to-male ratio of patients with ATC was significantly lower than that of patients with PTL (P=0.029). Both PTL and ATC commonly present as a relatively large, solid mass on sonography with compressive symptoms, in which hoarseness was seen more frequently in ATC group (66.7%) than in PTL group (14.8%) (P=0.001). There is no significant difference in thyroid size, nodular size, margin, shape, echo texture, echogenicity, cystic change, vascularity and local invasion on sonography between ATC and PTL groups. Echogenic strands, markedly hypoechoic and enhanced posterior echo were seen more frequently in PTL group (92.6%, 92.6%, and 85.2%, respectively) than those in ATC group (6.7%, 60.0%, and 33.3%, respectively) (P<0.05), and calcification was seen more frequently in ATC group (80.0%) than in PTL group (0%) (P<0.001). Three ultrasound patterns were observed for PTL including diffuse type (25.9%), nodular type (48.2%) and mixed type (25.9%), while all ATC cases presented with nodular type (100.0%). Associated Hashimoto's thyroiditis occurred more frequently in PTL group (59.3%) than in ATC group (20.0%) (P=0.023).

CONCLUSIONS

Certain sonographic features as a markedly hypoechogenicity, the presence of an enhanced posterior echo and linear echogenic strands, lack of calcification and associated Hashimoto's thyroiditis were valuable for distinguishing PTL from ATC. In contrast, heterogeneous echogenicity, uncircumscribed margin, irregular shape, and vascular pattern were not specific features for differential diagnosis.