Thyroid Nodules with Isolated Macrocalcifications: Malignancy Risk of Isolated Macrocalcifications and Postoperative Risk Stratification of Malignant Tumors Manifesting as Isolated Macrocalcifications

Abstract

Objective: To determine the malignancy risk of isolated macrocalcifications (a calcified nodule with complete posterior acoustic shadowing) detected on ultrasonography (US) and to evaluate the postoperative American Thyroid Association (ATA) risk stratification of malignant tumors manifesting as isolated macrocalcifications. Materials and Methods: A total of 3852 thyroid nodules (≥ 1 cm) of 3061 consecutive patients who had undergone biopsy between January 2011 and June 2018 were included in this study. We assessed the prevalence, malignancy rate, and size distribution of isolated macrocalcifications and evaluated the histopathologic features and postoperative ATA risk stratification of malignant tumors manifesting as isolated macrocalcifications. Results: Isolated macrocalcifications were found in 38 (1.2%) of the 3061 patients. Final diagnosis was established in 30 (78.9%) nodules; seven malignant tumors were diagnosed as papillary thyroid carcinomas (PTCs). The malignancy rate of the isolated macrocalcifications was 23.3% in the 30 nodules with final diagnoses and 18.4% in all nodules. Among the six surgically-treated malignant tumors, five (83.3%) had an extrathyroidal extension (ETE) (minor ETE 1, gross ETE 4), and two (33.3%) had macroscopic lymph node metastasis. Four (66.7%) malignant tumors were categorized as high-risk tumors, one as an intermediate-risk tumor, and one as a low-risk tumor using the ATA risk stratification. Histopathologically, out of the six malignant tumors, ossifications were noted in four (66.7%) and predominant calcifications in two (33.3%). Conclusion: The US pattern of isolated macrocalcifications (≥ 1 cm) showed an intermediate malignancy risk (at least 18.4%). All malignant tumors were PTCs, and most showed an aggressive behavior and a high or intermediate postoperative ATA risk.

Comparison of the diagnostic performance of the modified Korean Thyroid Imaging Reporting and Data System for thyroid malignancy with three international guidelines

“…However, extrathyroidal extension status was not evaluated in this study due to a lack of standardized US criteria. An isolated macrocalcification was defined as an entirely calcified nodule with posterior acoustic shadowing, in which no soft tissue component was identified due to dark shadows on the US image [ 19 - 21 ]. Such nodules were classified as "intermediate suspicion" based on the modified K-TIRADS, "moderate suspicion" (4 points) based on the ACR-TIRADS, and "unclassified" based on the other RSS [ 1 , 3 - 5 ].…”

Impact of the ultrasonography assessment method on the malignancy risk and diagnostic performance of five risk stratification systems in thyroid nodules

“…Among these, 998 nodules without nal diagnoses con rmed by surgical or de nite biopsy results (benign or malignant) and 8 nodules with US images of suboptimal quality were excluded. Among the 3826 nodules with nal diagnoses by surgical or biopsy results, 35 with isolated macrocalci cations (entirely calci ed nodules) [16] and 16 simple cysts were excluded because it was not possible to assess the nodule echogenicity. US images of thyroid nodules obtained between March 2017 and December 2019 before biopsy were prospectively evaluated by two radiologists, and 90 nodules that were prospectively assessed by a radiologist who did not review the US images of the retrospective dataset (January 2011 to February 2017) were excluded from the study population.…”

Different sonographic features of peripheral thyroid nodule calcification and risk of malignancy: a prospective observational study

“…Based on the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS), 3 types of echogenic foci are potentially linked to malignancy [ 6 , 7 ]: macrocalcifications, punctate echogenic foci, and peripheral rim calcifications (or eggshell calcifications). Macrocalcifications have been reported to carry a mild risk of malignancy, while punctate echogenic foci, which are mostly accompanied by psammomatous calcifications in papillary thyroid cancer, have been regarded with a high possibility of malignancy [ 8 , 9 ]. Nevertheless, the literature on the malignancy probability of rim calcifications has remained controversial [ 10 , 11 ].…”