Ultrasonographic Characteristics of the Hyperfunctioning Thyroid Nodule and Predictive Factors for Thyroid Stimulating Hormone Suppression

BACKGROUND AND OBJECTIVES: Thyroid scan is a good tool for diagnosis of hyperfunctioning thyroid nodules (HNs), however it has been limited in use in a primary clinical practice, because of its inconvenience and low accessibility. This study aimed to analyze ultrasonographic (US) characteristics of HNs and to predict HNs by US. MATERIALS AND METHODS: We included 114 patients who exhibited results of ‘hot’ nodule in the thyroid scan from 2008 to 2017. Analysis for US characteristics included 73 patients without unclear US images and other inevitable reasons. We compared US characteristics of HNs with cold nodules that showed “cold” in the thyroid scan. Additionally, we compared US characteristics of HNs between suppressed thyroid-stimulating hormone (TSH) (<0.25 uIU/mL) or normal TSH, and analysis receiver operating characteristics (ROC) curve for prediction of suppressed TSH among HNs. RESULTS: The HNs showed more partially cystic nodule, isoechoic echogenicity, hypervascularity and presence of halo in the US finding than the cold nodule. In subgroup analysis of nodules with TSH suppression among HNs, the TSH suppression nodules was lager in max size and volume than the normal TSH nodules. In ROC analyses for prediction of the TSH suppression among HNs, area under receiver operating characteristics curves was 0.736 in max size, 0.761 in volume. CONCLUSION: HNs showed more frequently partially cystic contents, isoechoic echogenicity, hypervascularity, and peripheral halo sign in US finding. Thyroid nodule size and volume were associated with suppressed TSH level of HNs, and optimal cutoff levels for prediction of TSH suppression among HNs were 2.6 cm and 1.13 cm3, respectively.

Papillary Thyroid Carcinoma Presented as a Hot Nodule with Hyperthyroidism

We report a case of a 74-year-old woman who was incidentally found to have a single thyroid nodule. Laboratory evaluation showed undetectable serum thyroid stimulating hormone and elevated free thyroxine levels. (99m)Tc thyroid scan showed a hyperfunctioning autonomous nodule in a right lobe of the thyroid. Thyroid ultrasonography showed a 2.2 cm sized nonhomogeneous spiculated nodule with microcalcification, and which was identical with the hyperfunctioning nodule confirmed in thyroid scan by (99m)Tc single photon emission computed tomography/computed tomography. Fine needle aspiration was done, and cytology reported as suspicious of malignancy. The patient underwent total thyroidectomy with central neck dissection, and pathology was consistent with papillary thyroid carcinoma. This case report demonstrates that diagnosis of a hyperfunctioning autonomous thyroid nodule does not preclude the possibility of thyroid cancer. Clinicians should consider further evaluation such as ultrasonography and fine needle aspiration in patients with hyperfunctioning autonomous nodules.

Hyperfunction Thyroid Nodules: Their Risk for Becoming or Being Associated with Thyroid Cancers

OBJECTIVE: To retrospectively evaluate the risk of thyroid cancer in patients with hyperfunctioning thyroid nodules through ultrasonographic-pathologic analysis. MATERIALS AND METHODS: Institutional review board approval was obtained and informed consent was waived. From 2003 to 2007, 107 patients consecutively presented with hot spots on thyroid scans and low serum thyroid-stimulating hormone levels. Among them, 32 patients who had undergone thyroid ultrasonography were analyzed in this study. Thyroid nodules depicted on ultrasonography were classified based on size and categorized as benign, indeterminate, or suspicious malignant nodules according to ultrasonographic findings. The thyroid nodules were determined as either hyperfunctioning or coexisting nodules and were then correlated with pathologic results. RESULTS: In 32 patients, 42 hyperfunctioning nodules (mean number per patient, 1.31; range, 1-6) were observed on thyroid scans and 68 coexisting nodules (mean, 2.13; range, 0-7) were observed on ultrasonography. Twenty-five patients (78.1%) had at least one hyperfunctioning (n = 17, 53.1%) or coexisting (n = 16, 50.0%) nodule that showed a suspicious malignant feature larger than 5 mm (n = 8, 25.0%), or an indeterminate feature 1 cm or greater (n = 20, 62.5%) in diameter, which could have been indicated by using fine needle aspiration (FNA). Seven patients were proven to have 11 thyroid cancers in 3 hyperfunctioning and 8 coexisting nodules. All of these had at least one thyroid cancer, which could have been indicated by using FNA. The estimated minimal risk of thyroid cancer was 6.5% (7/107). CONCLUSION: Patients with hyperfunctioning nodules may not be safe from thyroid cancer because hyperfunctioning nodules can coexist with thyroid cancer nodules. To screen out these cancers, ultrasonography should be performed.