Is ultrasound combined with computed tomography useful for distinguishing between primary thyroid lymphoma and Hashimoto’s thyroiditis?

Abstract

Introduction: The aim of the study is to investigate the usefulness of ultrasound combined with computed tomography (CT) for distinguishing between primary thyroid lymphoma (PTL) and Hashimoto's thyroiditis (HT). Material and methods: The investigation was conducted retrospectively in 80 patients from January 2000 to July 2018. All patients underwent pathological tests to be classified into one of two groups: PTL group and HT group. The cutoff value of CT density was determined using receiver-operating characteristic (ROC) curve analysis. The accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of diagnosis for thyroid by CT alone, ultrasound alone, and the combination of CT plus ultrasound were calculated. Results: Of the 80 study patients, 27 patients were PTL and 53 patients were HT. Mean CT density had a sensitivity of 90.6% and a specificity of 88.9% at a cutoff value of 53.5 HU, with area under the curve (AUC) 0.88. Ultrasound combined with CT had the highest specificity, accuracy, and PPV compared with CT alone and ultrasound alone (p value < 0.05). Conclusions: Features such as extremely hypoechogenicity, enhanced posterior echo, cervical lymphadenopathy in ultrasound image, and linear high-density strand signs, and very low density in CT imaging have high sensitivity and specificity in thyroid lymphoma. Therefore, ultrasound combined with CT may be useful for distinguishing between PTL and HT.

S-Detect Software vs. EU-TIRADS Classification: A Dual-Center Validation of Diagnostic Performance in Differentiation of Thyroid Nodules

“…Furthermore, the results of US strongly depend on the operator's interpretation and experience, which implies US sensitivity and specificity varying from 52% to 81% and 54% to 83%, respectively [8,9]. In some thyroid pathologies, additional imaging methods may be applied together with US to increase its diagnostic value [10,11]. Difficulties with the interpretation of US findings often lead to redundant FNAB or even diagnostic surgery.…”

Imaging of head and neck mucosa-associated lymphoid tissue lymphoma (MALToma)

“…MALToma is markedly hypoechoic (Figs. 1, 2, and 8a), may contain fibrous striations comprising fine linear echogenic strands or wider denser echogenic bands [17][18][19][20] (Figs. 1, 2, and 8a) and shows internal vascularity on colour Doppler [7] (Fig.…”

“…Internal striations and vascularity prevent misinterpreting a markedly hypoechoic MALToma for a cyst. Posterior acoustic enhancement is described [17][18][19] but is less frequently observed following advances in post-processing US technology [18,21]. US also guides the site of biopsy.…”

“…8) with imaging features as described above. These include markedly hypoechoic areas with internal vascularity and a striated appearance from linear echogenic strands and bands [17][18][19][20] (Fig. 8a and b).…”

“…MALToma may overlap with Hashimoto's disease although MALToma tends to be of lower density on non-contrast enhanced CT images [19], lower echogenic on US and cause more asymmetrical enlargement of the right and left lobes [17]. Like salivary gland MALToma, a history of recent swelling and evaluation for a dominant homogeneous solid nodule for biopsy are crucial.…”