Ultrasonographic differentiation of diffuse large B-cell lymphoma and mucosa-associated lymphoid tissue lymphoma in primary thyroid lymphoma.

[PURPOSE] The aim of this study was to evaluate the ultrasonographic differences between diffuse large B-cell lymphoma (DLBCL) and mucosa-associated lymphoid tissue (MALT) lymphoma in primary thyroid lymphoma (PTL).

[METHODS] A total of 46 patients with histopathologically confirmed PTL (27 with DLBCL and 19 with MALT lymphoma) were included in this study. All patients underwent ultrasonographic imaging prior to initiation of therapy. We retrospectively reviewed all images and compared the imaging findings between the two pathologies.

[RESULTS] DLBCL was more likely to demonstrate greater clinical aggressiveness than MALT lymphoma, as indicated by a significantly higher rate of perithyroidal tissue invasion (41% vs. 11%, = 0.025) and a lower proportion of asymptomatic cases (19% vs. 47%, = 0.036). The percentage of participants with lesions showing markedly hypoechoic echogenicity on ultrasound was 52% (14 of 27) in DLBCL group, compared with 5% (1 of 19) in MALT group ( = 0.001). Additionally, the mean maximum diameter of lesions was 62.5 ± 29.6 mm in DLBCL versus 38.1 ± 21.7 mm in MALT lymphoma ( = 0.004). Multivariable analysis showed that only hypoechoic lesions were independently associated with DLBCL (odds ratio 0.08; 95% CI 0.01-0.82).

[CONCLUSIONS] DLBCL is frequently characterized by markedly hypoechoic echogenicity, larger lesion size, and perithyroidal invasion on ultrasonography, whereas MALT lymphoma commonly presents with asymptomatic clinical manifestations.