Investigating the value of fine needle aspiration cytology in thyroid cancer

Thyroid US-guided FNA techniques: A prospective,randomized controlled study

BACKGROUND

Thyroid nodules are common in the general population. Ultrasonography is the most efficient diagnostic approach to evaluate thyroid nodules. The US FNAC procedure can be performed using either the short axis (perpendicular), or a long axis (parallel) approach to visualize the needle as it is advanced toward the desired nodule. The main aim of this study was to compare the percentage of non-diagnostic results between the long and short axis approach.

METHODS

A prospective study that included a randomized controlled trial and was divided into two arms-the short axis and the long axis-was conducted. A total of 245 thyroid nodules were collected through the fine needle aspiration cytology, performed with ultrasound, from march 2021 to march 2022. The patient's demographic information were collected and also nodules characteristics.

RESULTS

Of 245 nodules sampled, 122 were sampled with the long axis method, while 123 with the short axis method. There is not significantly less non diagnostic approach with either method compared to the other (11.5 % vs 16.3 % respectively).

DISCUSSION

Previous studies came to the conclusion that the long axis method yields fewer non diagnostic samples. This study evaluated the two FNA approaches which were proceeded by the same physician who is expert in both techniques.

CONCLUSION

The US FNAC performed in the long axis approach will not produce more conclusive results and less non diagnostic results (Bethesda category 1) than the short axis approach one.

Fine Needle Aspiration Cytology and Thyroglobulin Antibodies in Preoperative Diagnosis of Thyroid Malignancy

Introduction:

Most important in the evaluation of thyroid thyroid disease is to differentiate a disease that is treated medically from a disease that requires surgical treatment. In preoperative differentiation of a malignant from a benign lesion are used different diagnostic methods (US, scintigraphy, FNAC, MRI).

Aim:

The aim of the study was to determine the diagnostic value of fine needle aspiration cytology (FNAC) and serum thyroglobulin antibodies (TgAb) values in individual cytological categories.

Methods:

The prospective study included 100 patients with scintigraphic cold thyroid nodules divided into two groups. The first group consisted of 50 patients with histopathological verified benign nodules and the second group of 50 patients with histopathological verified benign nodules. Demographic datas, FNAC findings, TgAb levels and final histopathological findings were recorded. FNAC with ultrasound (US) guidance was performed by the so-called Free hand technique. TgAtb values were estimated by the radio-immunity assay (RIA) method.

Results:

In patients with histopathological findings of a benign nodule, 20 patients had a cytological finding of a colloidal nodule, 18 patients had a cellular nodule, 12 had a finding of follicular neoplasm. In patients with a histopathological finding of the malignant nodule, 9 patients had a cytological finding of a colloidal nodule, 8 had a cellular nodule, 21 follicular neoplasm and 12 patients had cancer. FNAC had a sensitivity of 66%, specificity of 76%, a positive predictive value of 73%, a negative predictive value of 69%. The highest preoperative serum TgAb values were in patients with cytologic findings of cancer, and the lowest in the cellular nodule.

Conclusion:

The finding of FNAC together with serum TgAb values contributes to better diagnosis and selection of patients requiring surgery.

Ultrasound Elastography is a Useful Adjunct to Conventional Ultrasonography and Needle Aspiration in Preoperative Prediction of Malignancy in Thyroid Nodules: A Northern India Perspective

INTRODUCTION

Data on ultrasound elastography (USE) are scant from India. This study aimed to compare the sensitivity and specificity of USE with thyroid ultrasonography (USG) and fine-needle aspiration (FNA) as preoperative predictor of malignancy, using postoperative histopathology as gold standard.

MATERIALS AND METHODS

Consecutive patients with thyroid swelling/goiter underwent thyroid USG followed by USE. Patients with pure cystic nodules or eggshell calcification were excluded. Patients with nodules >10 mm with one or more high-risk USG features underwent FNA. Patients with no USG high-risk features, benign score on USE, and benign FNA were conservatively followed. All other patients underwent thyroidectomy.

RESULTS

246 consecutive patients underwent USG. Data from 97 patients (117 nodules) were analyzed. Median age of patients was 43 years with 85.4% females. All patients with USE score-1 had benign USG and FNA characteristics. Of 86 nodules having USE score-2, 18.6% nodules were hypoechoic and 16.28% had microcalcification. Hypoechogenicity and microcalcifications were observed in 66.67% nodules with USE score-3. All nodules with USE score-4 and 5 were hypoechoic and had microcalcifications. Histopathology was benign in 84 and malignant in 33 patients. Occurrence of malignancy in USE scores 1-5 was 0, 4.65, 100, 90.5, and 100%, respectively. All eight nodules with diagnosis of follicular adenoma had preoperative USE score-2. The sensitivity of preoperative USG, USE, and FNA in picking up malignancy was 66.67, 87.88, and 69.70%, respectively. Specificity of USG, USE, and FNA in detecting thyroid malignancy was 88.10, 100, and 97.6%, respectively. False positivity rates for USG, USE, and FNA in diagnosing thyroid malignancy was 11.9, 0, and 2.4%, respectively. The overall diagnostic accuracy of USG, USE, and FNA cytology in this study was 82.05, 96.58, and 89.74%, respectively.

CONCLUSION

USE may be better than USG for preoperative detection of malignancy in thyroid nodules.

DO ALL THYROID NODULES >4 CM NEED TO BE REMOVED? AN EVALUATION OF THYROID FINE-NEEDLE ASPIRATION BIOPSY IN LARGE THYROID NODULES

OBJECTIVE

Controversy exists regarding the ability of fine-needle aspiration (FNA) biopsy to rule out malignancy when thyroid nodules exceed 4 cm in diameter. The goal of this study was to provide data regarding FNA accuracy in a clinical setting for detecting/ruling out malignancy in large thyroid nodules (≥4 cm) and discuss FNA utility in guiding surgical decisions.

METHODS

All thyroid FNA cases performed at Marshfield Clinic from 1/1/2000 to 12/31/2010 followed by complete or partial thyroidectomy on nodules of at least 4 cm were identified. Demographics, medical history, nodule biopsy characteristics, surgical procedures, and diagnosis data were abstracted. FNA was compared to histologic evaluation of surgical specimens.

RESULTS

A total of 198 patients with large thyroid nodules were identified. Most had a single large nodule, but ~40% were multinodular, and 206 total nodules were assessed. Females outnumbered males, and the mean age was ~50 years. After surgery, cancer was histologically identified in 49/206 (23.8%) nodules, including 9/123 nodules that had been categorized as benign by FNA, corresponding to a false-negative rate of 7.3%. Sensitivity/specificity for detecting malignancy by FNA was ~80%. The positive predictive value (PPV) was just below 60%, and the negative predictive value (NPV) was 93% but rose to 96% when papillary microcarcinomas were excluded.

CONCLUSION

While FNA sensitivity in large nodules was relatively low, NPV was high, especially if incidental papillary microcarcinomas were excluded. When cancer prevalence and NPV are known, FNA can be a reliable "rule out" test in nodules ≥4 cm. This information is critical and can help guide the surgery decision, especially in high-risk patients. The decision for surgery should not be solely based on nodule size but should consider additional factors including cancer prevalence, clinical history, ultrasound features, surgical risk, and life expectancy.

ABBREVIATIONS

FNA = fine-needle aspiration NPV = negative predictive value PPV = positive predictive value.

An analysis of trends of incidence and cytohistological correlation of papillary carcinoma of the thyroid gland with evaluation of discordant cases

Background:

The role of fine-needle aspiration cytology (FNAC) in thyroid nodules has been well-studied but there is a paucity of studies solely involving papillary thyroid carcinoma (PTC). The diagnostic criteria for PTC are established but still there is a worrisome possibility of false positive and false-negative results, which can have a serious impact on patient care. This article correlates the cytological and histological diagnosis of PTC with an eventual aim of analyzing the cause of false positive and false negative results in order to prevent misdiagnosis. An increase in the incidence of PTC in the younger population has been noted.

Aims:

To analyze the epidemiological trends and cytohistological correlation of PTC and evaluate the discordant cases and pitfalls of FNAC.

Materials and Methods:

Seventy-two cases who had undergone both FNAC and histopathological examination (HPE) of the thyroid gland were selected. Age and sex distribution as well as cytohistological correlation were done for all the cases.

Results:

Cytohistological correlation was 81.94%. False positives were 5.56% and the false negative rate was 13.2%. Sensitivity was 86.7% and the positive predictive value was 93.6%. The peak age was 31-40 years among females and 41-60 years among males. Seven of our patients were <20 years of age (10%).

Conclusion:

FNAC is an indispensible tool for the early diagnosis of PTC. However, certain conditions of the thyroid gland can cause diagnostic dilemma. Awareness of pathologists regarding these pitfalls can prevent misdiagnosis and provide better patient care. Increasing the incidence of PTC with a more striking increase in the younger population makes early diagnosis all the more important owing to better prognosis in this age group.

Diagnostic accuracy of fine needle aspiration cytology of thyroid and evaluation of discordant cases

INTRODUCTION

The main role of fine needle aspiration cytology (FNAC) lies in differentiating between a malignant and benign thyroid nodule. It greatly influences the treatment decision. The current study was undertaken to evaluate the cytology-histopathology correlation and to analyze the cause of diagnostic errors with an eventual aim to improve diagnostic accuracy.

MATERIALS AND METHODS

This is a retrospective study comparing cytology and corresponding histopathology report in 724 thyroid cases. The statistical analysis included false positive rate, false negative rate, sensitivity, specificity, positive predictive value, negative predictive value and accuracy.

RESULTS

On cytological examination, 635/724 were reported as benign, 68 malignant and 21 suspicious. On histopathological examination, 626/635 cases were confirmed as benign but there were 9 discordant cases. Among the other cases histopathology diagnosis of malignancy matched in 66/68 and 11/21 cases. Diagnosis correlated in 703/724 cases (97%) [p<0.001]. False positive and false negative rates were 1.9% and 10.5%, respectively. The sensitivity and specificity were 89.5% and 98%, respectively. The positive predictive value was 84.6% and negative predictive value was 98.6%. Accuracy of FNA was 97%.

CONCLUSION

In spite of high accuracy of FNAC in differentiating between a benign and malignant lesion, certain pitfalls should be kept in mind. The common false negative diagnoses were follicular pattern cases which constitute a 'gray zone', cystic papillary thyroid carcinoma (PTC) and papillary microcarcinoma. The reason for false positive diagnoses was the occurrence of nuclear features characteristic of PTC in other thyroid lesions. Awareness of pathologist regarding these pitfalls can minimize false negative/positive diagnoses.