Zhongguo quanke yixue (May 2022)
Ultrasonographic Analysis of Primary Thyroid Lymphoma
Abstract
Background Primary thyroid lymphoma (PTL) is a rare type of extranodal lymphoma, which is prone to misdiagnosis and missed diagnosis due to atypical clinical and ultrasonic features. Objective To summarize and analyze the features of 2-D ultrasonography and contrast-enhanced ultrasonography in PTL. Methods A retrospective, comparative analysis was conducted on ultrasonographic features of 16 patients with pathologically confirmed PTL (PTL group) and 16 thyroid cancer patients (thyroid cancer group) recruited from Tangshan Gongren Hospital during December 2012 to December 2020. Results Pathological results of PTL group: 10 cases were diffuse large B-cell lymphoma, 4 cases were mucous-associated lymphoid tissue extranodular marginal zone B-cell lymphoma, 1 case was follicular lymphoma, and 1 case was Burkitt lymphoma. Pathological results of thyroid cancer group: 11 cases were papillary carcinoma, 4 cases were follicular carcinoma and 1 case was medullary carcinoma. The rate of thyroid enlargement in PTL group was higher than that in thyroid cancer group (13/16 vs 5/16) (χ2=8.127, P<0.05) . PTL group also had higher rate of posterior echo enhancement (14/16 vs 3/16) (χ2=15.184, P<0.05) . Besides that, PTL group had lower calcification rate (0) than thyroid cancer group did (10/16) (χ2=14.545, P<0.05) . PTL and thyroid cancer groups had statistically differences in lesion morphology and margins (χ2=10.165, P<0.05) as 13 PTL cases had lesions with regular morphology and well-defined margins, and 12 thyroid cancer cases had lesions with irregular morphology and ill-defined margins. The rate of increased blood flow signals within the lesions showed no significant difference between PTL group and thyroid cancer group (7/16 vs 3/16) (χ2=3.327, P>0.05) . PTL and thyroid cancer groups also had no statistically significant difference in the rate of cervical lymph node metastases (8/16 vs 11/16) (χ2=1.166, P>0.05) . Contrast-enhanced ultrasonography showed high enhancement during arterial and venous phases in PTL, and low enhancement at arterial and venous phases in thyroid cancer. Conclusion PTL has specific ultrasonic manifestations. A diagnosis of PTL could be made when a patient manifests as thyroid enlargement, diffuse hypoechoic, non-calcified, regular-shaped lesions with well-defined margins and posterior echo enhancement, and high enhancement at arterial and venous phases.
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