Serial changes in ultrasound-guided fine needle aspiration cytology in subacute thyroiditis

The Old and the New in Subacute Thyroiditis: An Integrative Review

Subacute thyroiditis (SAT) is the most common cause of neck pain and thyrotoxicosis. Although this disease was recognized already by the end of the 18th century, new concepts regarding pathogenesis have emerged in recent years. Moreover, in the last two years, literature on SAT has increased significantly due to articles describing the possible connection with coronavirus disease 2019 (COVID-19). This integrative review depicts old and new concepts of this disease, proposing a detailed overview of pathogenesis, a practical approach to diagnosis and treatment, and a thorough description of the latest discoveries regarding the association of SAT with COVID-19.

Efficacy and safety of ultrasound-guided intrathyroidal injection of glucocorticoids versus routine oral administration of glucocorticoids for subacute thyroiditis: Protocol of systematic review and meta-analysis

BACKGROUND

This study was designed to systematically evaluate the clinical efficacy and safety of ultrasound-guided intrathyroidal injection of glucocorticoids (GCs) versus routine oral administration of GCs for subacute thyroiditis (SAT) and to help seek evidence of evidence-based medicine (EBM) for ultrasound-guided intrathyroidal injection of GCs in the treatment of SAT.

METHODS

Seven Chinese and English databases, including Chinese National Knowledge Infrastructure, Wanfang Data, VIP Information China Science and Technology Journal Database, SinoMed, PubMed, Cochrane Library, and Embase, were searched to collect randomized control trials on ultrasound-guided intrathyroidal injection of GCs in the treatment of SAT, which were published up to July 1, 2019. According to the method as described in Cochrane Reviewers' Handbook 5.1.0, the Cochrane Collaboration's tool for assessing risk of bias was employed to evaluate the quality of the literatures included. Statistical analysis was made by using Stata 12.0. The "metanif" command was used for sensitivity analysis to assess the stability of the results. Funnel diagram method, Egger linear regression method, and clipping complement method were used to evaluate publication bias.

RESULTS

This study was carried out in strict accordance with the standard procedures for meta-analysis in the Cochrane Reviewers' Handbook 5.1.0. Critical data about the primary and secondary outcome measures were obtained by statistical analysis.

CONCLUSION

This study would draw a definite conclusion about whether ultrasound-guided intrathyroidal injection of GCs is effective and safe in the treatment of SAT on the basis of EBM. This conclusion would provide scientific evidence for the clinical treatment of SAT.

Malignancy risk of oncocytic changes in thyroid nodules: who should we offer surgery to?

Background Oncocytic (Hürthle) cell in fine-needle aspiration biopsy (FNAB) remains challenging for surgeons. Surgical treatment is recommended for oncocytic change in FNAB, since it can sometimes be a struggle to determine the nature of thyroid nodules. We aimed to investigate the clinical significance of oncocytic changes in FNAB in terms of management of patients. Methods The FNAB samples of 172 patients with thyroid nodules were reviewed. Of these, 39 patients with cytologic findings of oncocytic changes on FNAB [POC: predominance of oncocytic cells; SFON-H: suspicious for follicular or oncocytic neoplasm (Hürthle cell type), SM-O: suspicious for malignancy-papillary or follicular carcinoma; oncocytic variant)] were included. Results FNAB demonstrated POC in 14 (35.8%), SFON-H in 15 (38.4%), and SM-O in 10 (25.6%) patients. The overall malignancy rate was 35.8% (n = 14). Clinical and laboratory data were not found to be associated with thyroid cancer while nodule size was significantly higher in patients with thyroid malignancy (15.2 versus 23.3 mm, p = 0.032). Regarding FNAB results including oncocytic changes, the rate of malignancy was significantly different and almost three-fold higher in nodules classified as SFON-H and SM-O [48% versus 14.2% with POC, p = 0.044]. Besides, there was a positive correlation between SFON-H and SM-O cytology and malignancy (p = 0.036, r = 0.337). Conclusions It is hard to discern the significance of oncocytic changes in FNAB report and to determine an optimal approach as a surgeon. We recommend surgery for the patients with an FNAB showing SFON-H and SM-O whereas POC should be better to be followed-up.

Sonographic features of thyroid nodules that may help distinguish clinically atypical subacute thyroiditis from thyroid malignancy

OBJECTIVES

The purpose of this study was to evaluate sonographic features for distinguishing clinically atypical subacute thyroiditis from malignant thyroid nodules.

METHODS

A total of 165 hypoechoic thyroid nodules without calcification in 135 patients with histologic diagnosis were included in this study. These nodules were classified into 2 groups: a thyroiditis group (55 nodules in 36 patients) and a malignancy group (110 nodules in 99 patients). The sonographic features of the groups were retrospectively reviewed.

RESULTS

No significant differences were detected for the variables of marked echogenicity, a taller-than-wide shape, and mixed vascularity. However, a poorly defined margin was detected more frequently in the thyroiditis group than the malignancy group (P < .05); it yielded a high capability for differential diagnosis of atypical subacute thyroiditis, with sensitivity and specificity of 87.3% and 80.9%, respectively. Centripetal reduction echogenicity was observed exclusively in the thyroiditis group, with high specificity (100%) but low sensitivity (21.8%) for atypical subacute thyroiditis diagnosis. All of the thyroiditis nodules with a positive color signal showed noninternal vascularity (negative predictive value, 100%).

CONCLUSIONS

There is a considerable overlap between the sonographic features of atypical subacute thyroiditis and thyroid malignancy. However, the margin, echogenicity, and vascularity type are helpful indicators for differential diagnosis of atypical subacute thyroiditis.

Papillary thyroid cancer case masked by subacute thyroiditis

Subacute thyroiditis (SAT) association with thyroid carcinoma has been rarely reported in the literature. We present a patient with SAT and papillary thyroid cancer that was suspected by ultrasonographic evaluation (US) following SAT treatment. A fifty-four-year old female patient referred to our department due to tachycardia, jitteriness and pain in cervical region for the past one month. SAT diagnosis was established by physical examination, laboratory and ultrasonographic findings. After treatment, control thyroid US revealed regression of the hypoechogenic regions seen in both lobes, and a previously unreported hypoechogenic lesion with microcalcification focus that had irregular borders and was not clearly separated from the surrounding parenchyma located in the posterior aspect of the lobe (Elasto score: 4, Strain index: 7.08). Fine needle aspiration biopsy was taken from this nodule; cytology was assessed to be compatible with papillary thyroid carcinoma. Postsurgical pathology evaluation showed a papillary microcarcinoma. SAT may produce ultrasound changes that obscure the coexistence of papillary carcinoma. We recommend that patients with SAT have ultrasonography after they recover. Hypoechogenic regions bigger than 1 cm that are present in the follow-up post-therapy US should be assessed by biopsy.

Papillary carcinoma obscured by complication with subacute thyroiditis: sequential ultrasonographic and histopathological findings in five cases

BACKGROUND

Subacute thyroiditis (SAT) has been rarely reported to coexist with thyroid carcinomas. The objective of the study was to assess sequential ultrasonographic and histopathological findings of SAT in the context of complicating thyroid carcinomas.

METHODS

Of 1152 patients with SAT who visited our thyroid clinic at Kuma Hospital from 1996 through 2006, 5 cases complicated by papillary carcinoma underwent surgical resection 3-16 months after SAT onset. Ultrasonographic examinations and thyroid function tests were performed in all patients at onset of SAT and just before surgery. Sequential histopathological features of regenerated thyroid and carcinoma involvement were evaluated.

RESULTS

Heterogenous areas with microcalcifications in the thyroid or lymphadenopathy in three patients were clues for the nodular involvement with papillary carcinoma on the initial ultrasonographic examination. In contrast, diffuse hypoechoic change in the thyroid in two patients made it impossible to differentiate nodular involvement from inflammatory lesion. Histopathological examination of surgical specimens showed granulomatous and fibrotic changes. These were present about 3 months from SAT onset, and residual fibrosis remained several additional months, in the condition of no inflammatory hypoechoic lesions. In the areas of papillary carcinoma overlapping with transient inflammatory involvement, some lymphocytes and fibrotic changes were present in the stroma of papillary foci, but no granulomatous formation was present in any sections. Continuity with fibrosis around regenerated follicular cells was absent. The degree of lymphoid infiltrate and fibrotic change in the papillary carcinoma was not dependent on periods between SAT onset and the resection.

CONCLUSIONS

SAT may produce ultrasound changes that obscure the coexistence of papillary carcinoma, but affects no lymphoid infiltrate and fibrotic changes involved in carcinoma throughout the clinical course. We recommend that patients with SAT have ultrasonography after they recover. Further workup, including cytological examination of hypoechoic regions, should be performed if they are present as measuring 1 cm or larger.

Diagnostic terminology and morphologic criteria for cytologic diagnosis of thyroid lesions: a synopsis of the National Cancer Institute Thyroid Fine-Needle Aspiration State of the Science Conference

The National Cancer Institute (NCI) sponsored the NCI Thyroid Fine-needle Aspiration (FNA) State of the Science Conference on October 22-23, 2007 in Bethesda, MD. The two-day meeting was accompanied by a permanent informational website and several on-line discussion periods between May 1 and December 15, 2007 (http://thyroidfna.cancer.gov). This document summarizes matters regarding diagnostic terminology/classification scheme for thyroid FNA interpretation and cytomorphologic criteria for the diagnosis of various benign and malignant thyroid lesions. (http://thyroidfna.cancer.gov/pages/info/agenda/).

Subacute thyroiditis: Fine-needle aspiration cytology of 14 cases presenting with thyroid nodules

Subacute thyroiditis (SAT) is usually diagnosed clinically without the need for fine-needle aspiration. The cytologic literature on this condition is therefore rare. We report on 14 cases of SAT presenting with thyroid nodules. The majority of patients were women with a mean age of 46 yr. All had pain/tenderness in the thyroid area accompanied by fever or an elevated ESR. The salient cytologic features included cellular smears; multinucleated giant cells in 100% of cases, some ingesting colloid or neutrophils; fibrous fragments with enmeshed inflammatory cells were a constant feature; follicular cells were scant to absent in most cases. Granulomas were rare. Colloid, when present was thick, with central cracks and frayed edges. One case was suspicious for malignancy. We conclude that the cytologic features of SAT are predictable, particularly, in the appropriate clinical setting. FNA is also helpful in ruling out concomitant neoplastic conditions.

Cytological correlation in patients who have a pre-diagnosis of thyroiditis ultrasonographically

OBJECTIVE

Radiological-cytopathological correlation in patients who are prediagnosed ultrasonographically as thyroiditis.

STUDY DESIGN

Fourty five patients with hypoechogenic, heterogeneous, and/or pseudolobulated thyroid gland sonographically were included in this prospective study. Except for the patients with subacute thyroiditis, none of the patients had a prediagnosis of thyroiditis clinically. All patients were evaluated for their thyroid gland functions and intraglandular vascularity and ultrasonography-guided fine needle aspiration biopsy (US-FNAB) was performed.

RESULTS

The diagnosis of thyroiditis was confirmed in 36 patients (16 lymphocytic thyroiditis, 20 Hashimoto thyroiditis, two subacute granulomatous thyroiditis) in sonographically suspected patients. In six patients, FNAB was thyroiditis negative. The true diagnosis ratio of thyroiditis was increased up to 81.8% (%95 Confidence Interval: 0.70-0.92) by performing US-FNAB, while it was 4.5% with only clinical and laboratory findings (p=0.0001).

CONCLUSION

Hypoechogenic, heterogeneous thyroid gland may be strongly related to thyroiditis, which does not have any specific radiological findings. The sonographic finding of generalized parenchymal abnormality should alert the clinician to consider diffuse thyroid disease as the underlying cause and FNAB should be performed and a follow-up examination of these patients must be continued due to the risk of neoplastic disease of thyroid.

Ultrasound-guided fine-needle aspiration and thyroid disease

BACKGROUND

Fine-needle aspiration represents a critical diagnostic test in determining proper management of thyroid disease and the use of ultrasound-guided fine-needle aspiration (USGFNA) has increased over the years.

METHODS

A retrospective chart review of patients undergoing USGFNA. Two hundred fifteen patients underwent 234 procedures with 362 nodules aspirated within a 2 (1/2)-year period.

RESULTS

The mean ages of women and men were 51.9 and 57.8, respectively. The average size of nodules was 2.1 cm. A difficult to assess gland or nodule was the most common indication for USGFNA (33%). The sensitivity was 88.2%, specificity was 80.0%, the PPV was 65.2%, the negative predictive value was 94.1%, and the accuracy was 82.5%. The cancer yield, inadequacy, and complication rates were 44%, 10.5%, and 8.5%, respectively.

CONCLUSIONS

USGFNA aspiration is a safe and effective diagnostic modality in the management of thyroid disease, especially for nodules that are difficult to palpate.

The value of ultrasonography in predicting autoimmune thyroid disease

Ultrasonography (US) may demonstrate a diffuse reduction in thyroid echogenicity (low-amplitude echoes) in autoimmune thyroid disease (AITD), which includes chronic lymphocytic thyroiditis and Graves' disease, as well as in subacute thyroiditis. The reported occurrence of this finding in AITD varies from 19% to 95%. To assess the validity of diffuse reduction in thyroid echogenicity as a predictor of AITD, 3,077 patients referred for US of the thyroid were examined prospectively with regard to reduced versus normal thyroid echogenicity. The most frequent reasons for referral were goiter, thyroid dysfunction, neck discomfort, and/or difficulty in swallowing. Ultrasonography demonstrated diffuse reduction in thyroid echogenicity in 485 patients. Of these, 452 patients had available records of fine-needle aspiration biopsy (FNAB), and were included in the study. From the remaining patients, with normal thyroid echogenicity, 100 consecutive patients were selected as controls. In 411 of the 452 study patients (90.9%) there was at least one laboratory finding consistent with possible AITD: cytology indicating lymphocytic thyroiditis, 287 of 363 patients (79.1%) with diagnostic specimens; elevated levels of peroxidase antibodies (TPOAb), 225 of 337 (66.8%); elevated thyrotropin (TSH) levels, 290 of 450 (64.4%); or low TSH levels, 79 of 450 (17.6%). The final diagnosis was: chronic autoimmune (Hashimoto's) thyroiditis in 352 patients; Graves' disease in 47 patients; subacute (granulomatous) thyroiditis in 7 patients; toxic nodular goiter in 3 patients; and toxic adenoma in 2 patients. In the remaining 41 patients, those without laboratory results consistent with AITD, the final diagnosis was colloid goiter in 37 and thyroid cancer in 4 patients. In the 100 controls, laboratory results were consistent with possible AITD in 14 patients: elevated TPOAb levels in 5 of 49 patients with retrieved antibody results; lymphocytic thyroiditis in 2 patients; elevated TSH levels in 2 patients; and low TSH levels in 2 patients. In these controls, the final diagnosis was: chronic autoimmune thyroiditis in 7; toxic nodular goiter in 6 patients, and toxic adenoma in 1 patient. The corresponding positive and negative predictive values of reduced thyroid echogenicity as an indicator of AITD were 399 of 452 (88.3% [95% CI, 85% to 91%]), and 93 of 100 (93.0% [95% CI, 88% to 98%]), respectively. Thus, diffuse reduction in thyroid echogenicity was a valid predictor of AITD.