Tumor Growth Rate Does Not Predict Malignancy in Surgically Resected Thyroid Nodules Classified as Bethesda Category III with Architectural Atypia

The associated factors for spontaneous intranodular hemorrhage of partially cystic thyroid nodules: A retrospective study of 101 thyroid nodules

ABSTRACT

Spontaneous intranodular hemorrhaging in benign partially cystic thyroid nodules was reported to cause neck swelling, difficulty swallowing, and other oppressive symptoms attributed to their growing progressively at high rates. In our study, the risk factors for hemorrhaging in these nodules were investigated.We retrospectively analyzed benign partial cystic thyroid nodules from September 2017 to December 2019, and divided them into 2 groups according to the occurrence of intranodular hemorrhage. Age, gender, follow-up time nodules initial maximum diameter, blood supply, spongiform content, nodules solid components, and internal solid portion were compared between the 2 groups at the first ultrasound examination. Chi-Squared and multivariate analysis were performed to evaluate the association of hemorrhage with clinical and ultrasonographic characteristics. ROC analysis was performed to evaluate the utility of factors in predicting hemorrhage.There were 59 occurrences of intranodular hemorrhage, which were associated with abundant blood supply, spongiform contents, and unsmooth margin of the internal solid portion. After multivariate analysis, abundant blood supply, and spongiform content were independent predictors for hemorrhage. In ROC analysis integrating these predictors, the sensitivity was 62.7% and specificity was 95.2% with the AUC 0.881.Partially cystic thyroid nodules with abundant blood supply, non-smooth margin of the internal solid portion and a spongiform internal content were apt to spontaneous intranodular hemorrhaging, which can be recognized as soon as possible by ultrasound.

Thyroid paraganglioma accompanied by lymph node metastasis or trachea invasion: A case report

Thyroid paraganglioma (TP) is an uncommon neuroendocrine tumor with potential for misdiagnosis. Case 1 (male; 44 years old) presented with hoarseness for 3 months. A 2.5-cm gray nodule in the left thyroid was diagnosed as TP by immunohistochemistry. Lymph node metastasis was confirmed by H&E staining and immunohistochemistry. The patient was followed-up for 3 years without any signs of recurrence or metastasis. Case 2 (female; 39 years old) presented with an asymptomatic but rapidly growing thyroid nodule. The patient underwent thyroidectomy 8 years ago (2008) and was diagnosed with TP postoperatively. The patient was diagnosed with recurrence and exhibited trachea invasion. Thyroidectomy and partial trachea resection were performed. A literature review revealed that 62 other cases of TP have been reported, and most of them exhibited low malignant potential. However, the two cases presented in the current case report exhibited a high malignant potential, accompanied by lymph node metastasis or trachea invasion, and these features imply that the choice of treatment for patients should be based on their different degrees of malignancy.

Strategy to reduce unnecessary surgeries in thyroid nodules with cytology of Bethesda category III (AUS/FLUS): a retrospective analysis of 667 patients diagnosed by surgery

PURPOSE

Fine-needle aspiration (FNA) is widely used for the diagnosis of thyroid nodules detected by ultrasonography. However, the cytology of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) often leads to unnecessary thyroid surgery. This study aimed to identify a strategy to reduce unnecessary surgeries in patients with AUS/FLUS nodules.

METHODS

Medical records of 667 patients with the cytology of AUS/FLUS who underwent surgery from January 2007 to December 2017 were retrospectively reviewed. Clinicopathological data were analyzed to identify malignant factors in thyroid nodules with AUS/FLUS. Factors were compared between patients with thyroid cancer and those with benign thyroid nodules, using stepwise multivariate logistic regression and decision tree model.

RESULTS

Pathological thyroid cancer was identified in 193 (43.3%) patients. There was a significant difference in malignancy incidence with respect to family history, number of nodules, number of FNAs, ultrasonographic finding, lymphocytic thyroiditis, and BRAFV600E mutation. Multivariate analysis showed that ultrasonography (K-TIRADS 5) was the most influential independent predictor of malignancy in AUS/FLUS (odds ratio = 11.02, p < 0.001), followed by possessing BRAFV600E mutation (odds ratio = 4.54, p < 0.001). This strategy enabled 226 (89.3%) patients to avoid unnecessary surgeries based on the decision tree model. There was no node of repeated FNA in the decision tree model, which reduced the risk of malignancy (odds ratio = 0.35, p = 0.029).

CONCLUSION

K-TIRADS 5 and BRAFV600E mutation were predictive of malignancy in nodules of AUS/FLUS. These factors should be considered in strategies to reduce unnecessary surgeries for AUS/FLUS.

Determining Whether Tumor Volume Doubling Time and Growth Rate Can Predict Malignancy After Delayed Diagnostic Surgery of Follicular Neoplasm

Background: Tumor volume doubling time (TVDT) is considered as a dynamic indicator of tumor growth and progression. We aimed to clarify whether TVDT should be considered in the cytological diagnosis of follicular neoplasms (FNs). Methods: This retrospective cohort study included 100 consecutive FN patients with a TVDT >1 year for whom surgical resection was delayed for >1 year. Changes in tumor volume and the TVDT of each nodule were calculated by serial neck ultrasonography (US) over a median follow-up of 50 months. Results: Among 100 surgically resected FNs, 58 (58%) were benign and 42 (42%) were malignant tumors. At the 5-year follow-up, most FN nodules showed volume increases of >50%, accounting for 65% of benign and 62% of malignant nodules. No significant difference was observed in tumor growth rates and time to a >50% increase in tumor volume between benign and malignant nodules (p = 0.299 and p = 0.378, respectively). The calculated TVDT and a >50% volumetric increase showed a linear relationship with a high concordance (R² = 0.883; p < 0.001). The risk of malignancy was not significantly associated with TVDT (relative risk = 1.00; [95% confidence interval 0.99-1.01]; p = 0.784). Even when US features were considered, no significant association was found between TVDT and the risk of malignancy. Conclusions: The size of most FNs increased exponentially with time; the tumor growth rates of benign and malignant nodules were similar. Despite the usefulness of TVDT as an indicator of growing velocity of FN nodules, TVDT could not predict malignancy in FNs. Clinical surveillance based on the growth of thyroid nodules categorized as FNs on serial neck US does not predict the risk of malignancy.

THYROID NODULE GROWTH AS A PREDICTOR OF MALIGNANCY

Objective: To assess which measure of thyroid nodule growth on serial neck ultrasound, if any, is associated with malignancy. Methods: Retrospective exploratory chart review of malignant thyroid nodules assessed at Kingston Health Sciences Centre (2006-2016) and benign thyroid nodules (2016), at least 1 cm in diameter and with 2 ultrasounds completed at least 30 days apart. Groups were compared using independent samples Student's t test, chi-square test, or Mann-Whitney U test as appropriate, as well as multivariable logistic and linear regression modelling to adjust for age and baseline volume. Results: One hundred and seventy-eight nodules were included in the study. When growth was defined as >20% increase in 2 dimensions (minimum 2 mm), malignant nodules (MNs) underwent significantly more growth than benign nodules (BNs) (16.8% BN versus 29.8% MN [P = .026]; odds ratio = 2.49; 95% confidence interval = 1.12 to 5.56). There was no significant difference between the groups when growth was defined as >2 mm/year or ≥50% volume growth. Nodules shrank >2 mm/year in each group and the difference was not statistically significant (24.2% BN versus 20.7% MN [P = .449]). The median doubling time for the nodules that grew was 1022.1 days in the BN group and 463.2 days in the MN group (P = .036). The median doubling time for all nodules was 456.5 days in the BN group and 244.2 days in the MN group (P = .015). Conclusion: Thyroid nodule growth defined as >20% increase in 2 dimensions (minimum 2 mm) is associated with risk of malignancy. Nodule shrinkage did not distinguish between BNs and MNs. Abbreviations: BN = benign nodule; CI = confidence interval; FNA = fine needle aspiration; KHSC = Kingston Health Science Centre; MN = malignant nodule; OR = odds ratio; ROC = receiver operating characteristic.