Primary thyroid lymphoma associated with metastatic thyroid tumor: discrimination with US

Contrast-Enhanced Ultrasound in the Differential Diagnosis of Primary Thyroid Lymphoma and Nodular Hashimoto's Thyroiditis in a Background of Heterogeneous Parenchyma

Objective

To investigate the diagnostic performance of contrast-enhanced ultrasound (CEUS) in the differentiation of primary thyroid lymphoma (PTL) and nodular Hashimoto’s thyroiditis (NHT) in patients with background of heterogeneous diffuse Hashimoto’s thyroiditis (HT).

Methods

Sixty HT patients with 64 thyroid nodules (31 PTL and 33 NHT) who had undergone CEUS examination were included in this study. With histopathological results as the reference, we evaluated the imaging features of each nodule on both conventional ultrasonography (US) and CEUS. Quantitative CEUS parameters including peak intensity (PI), time to peak (TTP), and area under the time–intensity curve (AUC) were gathered in the nodule and background parenchyma. The ratio indexes of theses parameters were calculated by the ratio of the lesion and the corresponding thyroid parenchyma. Logistic regression and receiver operating characteristic (ROC) curves analyses of valuable US indicators were further preformed to evaluate the diagnostic capability of CEUS in discrimination of PTL and NHT.

Results

Among all the observed US imaging features and CEUS parameters, 10 indicators showed significant differences between PTL and NHT (all P < 0.05). All the significant indicators were ranked according to the odds ratios (ORs). Eight of them were CEUS associated including imaging features of enhancement pattern, degree, homogeneity, and quantification parameters of PI, AUC, ratios of PI, AUC, and TTP, while indicators on conventional US, including vascularity and size ranked the last two with ORs less than 3. The five single CEUS parameters showed good diagnostic performance in diagnosis of PTL with areas under ROC curves of 0.72–0.83 and accuracies of 70.3–75.0%. The combination of CEUS imaging features and the ratios of PI, AUC, and TTP demonstrated excellent diagnostic efficiency and achieved area under ROC curve of 0.92, which was significantly higher than any of the five single parameters (all P < 0.05), with a sensitivity of 83.9%, specificity of 87.9%, and accuracy of 85.9%.

Conclusions

CEUS is an efficient diagnostic tool in the differential diagnosis of PTL and NHT for patients with diffuse HT. Conjoint analysis of CEUS imaging features and quantification parameters could improve the diagnostic values.

Thyroid Lymphoma: A Single Institution's Experience

BACKGROUND: Primary lymphoma of the thyroid gland is uncommon.

METHODS: The tumor registry at the Penn State Milton S. Hershey Medical Center was searched for all patients carrying a diagnosis of thyroid lymphoma. All available records for these patients were examined and information regarding patient and tumor characteristics, clinical presentation, interventions, and survival were tabulated.

RESULTS: The average age of patient in our series was 67.5 years. There was a 2.7:1 female to male preponderance. Thirteen (60%) patients presented with thyroid nodule(s). Eleven (50%) presented with aerodigestive tract obstructive symptoms. Sixteen (73%) patients had no pre-existing history of thyroid disease; none had known pre-existing Hashimoto's thyroiditis.

CONCLUSIONS: The typical thyroid lymphoma patient is female and elderly with painless thyroid enlargement. Compressive symptoms of the aerodigestive tract are common at presentation and may require urgent intervention. Treatment modalities (XRT, CHOP chemotherapy) and outcomes are distinct from other thyroid malignancies.

EBM RATING: C