Non-diagnostic Fine Needle Aspiration Cytology Research Articles

Repetition of thyroid fine-needle aspiration cytology after an initial nondiagnostic result: Is there an optimal timing?

IntroductionIt is suggested to wait at least 3 months to repeat a fine needle aspiration cytology (FNAC) to avoid possible inflammatory cytological changes induced by a previous procedure. This study evaluated the influence of the interval between 2 FNACs in a cohort with a previous non-diagnostic (ND) FNAC. We analysed the occurrence of ND or atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) results in the second FNAC, based on the intervals between procedures. Patients and methodsRetrospective study (2017–2020) including thyroid nodules with a ND result, subjected to another FNAC. Demographic, clinical and echographic data, interval between FNACs and their results were collected. We considered the intervals: ≤/>3 months and ≤/>6 months. Second FNAC results were classified as ND, AUS/FLUS or diagnostic (including the other Bethesda categories). ResultsIncluded 190 nodules (190 patients – 82.1% women, mean age 60±13.7 years) with a first ND FNAC. The second FNAC results were: ND in 63 cases, AUS/FLUS in 9 and diagnostic in 118 cases. There were no statistical differences in FNAC results performed≤3 months (13 ND, 2 AUS/FLUS, 19 diagnostic) vs >3 months (50 ND, 7 AUS/FLUS, 99 diagnostic; p=0.71). Similarly, there were no statistical differences considering a longer time interval: ≤6 months (32 ND, 3 AUS/FLUS, 59 diagnostic) vs >6 months (31 ND, 6 AUS/FLUS, 59 diagnostic; p=0.61). ConclusionsTime interval between FNACs was not relevant to the final cytological result. Early FNAC repetition did not increase the cases of ND or AUS/FLUS.

SAT454 Repetition Of Fine Needle Aspiration Cytology After An Initial Nondiagnostic Result: Does An Optimal Timing Exist?

Abstract Disclosure: I. Cosme: None. E.L. Nobre: None. M.J. Bugalho: None. Background: The optimal time to repeat a fine-needle aspiration cytology (FNAC) of a thyroid nodule, after a nondiagnostic (ND) result, is not established. It has been proposed to wait at least 3 months for a 2nd FNAC, in order to mitigate the possible inflammatory cytological changes induced by a previous FNAC. This study aimed to evaluate whether the time between 2 consecutive FNACs, influences the final cytological result. We analysed the occurrence of ND or atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) in the 2nd FNAC, in different repetition time intervals. Methods: Retrospective study (2017-2020) including thyroid nodules with a first ND FNAC, submitted to a 2nd FNAC. All FNACs were ultrasound-guided. Demographic data, time interval between FNACs and their results were collected. The 2nd FNAC results were analysed according to FNACs´ repetition interval. We considered 2 intervals: ≤ vs > 3 months and ≤ vs >6 months after the initial FNAC. The 2nd FNAC results were classified as ND, AUS/FLUS or diagnostic (including the other Bethesda FNAC categories). Results: Included 190 nodules (190 patients, 82.1% women, mean age 60±13.7 years) with a 1st ND FNAC submitted to a 2nd FNAC. The 2nd FNAC result remained ND in 63 cases, was AUS/FLUS in 9 and diagnostic in 118 (benign in 116 cases, follicular neoplasm/suspicious follicular neoplasm in 1 and malignant in 1 case). There were no statistical differences in 2nd FNAC result performed ≤3 months (13 ND, 2 AUS/FLUS, 19 diagnostic) vs >3 months (50 ND, 7 AUS/FLUS, 99 diagnostic) - p=0.71. Considering a wider time interval between FNACs, there were also no statistical differences in the 2nd FNAC result: ≤ 6 months (32 ND, 3 AUS/FLUS, 59 diagnostic) vs >6 months (31 ND, 6 AUS/FLUS, 59 diagnostic) - p=0.61. Conclusions: The time interval between FNACs was not relevant to the final cytological result. Early FNAC repetition did not increase the cases of ND or AUS/FLUS. Presentation: Saturday, June 17, 2023

Factors for second non-diagnostic ultrasound-guided fine-needle aspiration cytology in thyroid nodules

IntroductionResults in fine-needle aspiration cytology (FNAC) of thyroid nodules may be non-diagnostic (ND). In these cases, it is recommended to repeat the FNAC. The aim of our study was to evaluate the influence of demographic, clinical and ultrasound (US) characteristics in the recurrence of an ND result in thyroid nodule FNAC. MethodsA retrospective study of ND thyroid nodule FNAC was performed for the period 2017–2020. Demographic and clinical data (age, gender, cervical radiotherapy, presence of Hashimoto's thyroiditis, and TSH value) and US characteristics (nodule size, echogenicity, composition and microcalcifications) were collected at first ND FNAC. ResultsOut of 230 nodules with first ND FNAC (83% women; mean age 60.2±14.1 years), 195 (84.8%) underwent a second FNAC: 121 benign, 63 non-diagnostic, 9 indeterminate and 2 malignant. Nine (3.9%) underwent surgery, only 1 of which showed malignant histology and 26 (11.3%) remained under US monitoring. Demographically, patients with second ND FNAC were older (63.4±14 vs. 59±14 years; P=0.032). Females had lower risk of second ND FNAC (OR, 0.4, 0.2–0.9; P=0.016); risk of second ND FNAC was higher in patients treated with anticoagulant/antiplatelet drugs (OR, 2.2, 1.1–4.7; P=0.03). Previous cervical radiotherapy, family history of thyroid cancer, Hashimoto's thyroiditis and TSH value did not influence the risk of second ND FNAC. On US, nodule echogenicity differed significantly between the ND and diagnostic FNAC, with greater risk of an ND result in hypoechogenic nodules. Microcalcification increased the risk of ND FNAC (OR 2.2, 1.1–4.5; P=0.03). Nodule composition and size did not significantly differ according to ND or diagnostic second FNAC. ConclusionMale gender, advanced age, anticoagulant/antiplatelet drug therapy, hypoechogenic nodules and microcalcified nodules are likely factors for second ND FNAC. Nodules with two ND FNACs were rarely malignant, and a more conservative approach in these cases is not unsafe.

SCC Antigen Concentrations in Fine-Needle Aspiration Samples to Detect Cervical Lymph Node Metastases: A Prospective Analysis.

To determine the diagnostic value of measuring squamous cell carcinoma antigen (SCC-Ag) and cancer antigen 15-3 (CA15-3) concentrations in fine-needle aspiration (FNA) samples for the detection of squamous cell carcinoma (SCC) metastases in cervical lymph nodes. A prospective study with patients consecutively included between November 2018 and May 2021. A tertiary head and neck oncologic center. Out of 138 patients, SCC-Ag concentrations were analyzed in 168 FNA cervical lymph node samples and CA15-3 in 152 samples. Results were compared with FNA cytology (FNAC) or definitive histology to establish sensitivity and specificity rates. For the detection of cervical SCC lymph node metastases, SCC-Ag measurement had an 89.4% sensitivity and 79.3% specificity at a cutoff concentration of 0.1 µg/L. Measurement of CA15-3 concentration in addition to SCC-Ag concentration did not lead to improved accuracy for the detection of SCC. In histology-confirmed cases, FNAC had an 80.0% sensitivity and 100% specificity, as opposed to 93.3% and 57.1%, respectively, for SCC-Ag. Measurement of SCC-Ag concentration for detection of SCC lymph node metastases has a sensitivity at least comparable to FNAC and could be used as a relatively cheap screening tool in samples with nondiagnostic or indeterminate FNAC results or when multiple lymph nodes are sampled. However, SCC-Ag in FNA samples has a lower specificity than FNAC assessed by pathologists experienced in head and neck oncology. Addition of CA15-3 measurement did not lead to improved accuracy.

Surgeon-performed ultrasound with fine-needle aspiration biopsy for the diagnosis of parotid gland tumors.

Ultrasound (US) with or without fine-needle aspiration cytology (FNAC) are readily available and can offer in office and rapid diagnosis of parotid lumps. We analyzed 398 of patients who underwent blind FNAC or US with FNAC performed by an operating head and neck surgeon. Specificity, sensitivity, as well as accuracy were calculated for US alone, FNAC alone, and US-FNAC combined. Nondiagnostic US-guided FNAC rate was 3.1% and 7.2% for blind FNAC. With those cases removed, final accuracy for US alone in diagnosis of malignancy, pleomorphic adenoma (PA), and Warthin tumor (WT) were 90.8%, 81%, and 77.4% respectively. For US-FNAC accuracy for malignancy, PA, and WT were 92.1%, 94 0.8%, and 95.4% respectively. US with FNAC is cost-effective and rapid diagnostic tool and may help surgeon to deliver more accurate informed consent to a patient.

Improving our departmental reporting of thyroid cytology specimens against national guidelines: A two-cycle retrospective audit.

In the UK, guidelines from the Royal College of Pathologists (RCPath) facilitate consistent and reproducible reporting and classification of fine needle aspiration cytology (FNAC) thyroid specimens. The aim was to audit our department against RCPath guidelines to refine and improve our reporting process. Two-cycle retrospective observational audit of all patients undergoing thyroid FNAC over a 2-year period (1year for each cycle). Final histology was correlated. The positive predictive value (PPV) for malignant neoplastic lesions was calculated; for Thy1, Thy1c, Thy2 and Thy2c all cases without final histology were assumed to be benign, while for Thy3a, Thy3f, Thy4 and Thy5 samples the PPV calculation was based only on those cytology samples with corresponding histology. False positive and false negative cases were reviewed. In total, 288 cytology samples were included in the first cycle; 96 (33.3%) had corresponding histology. There were 287 samples included in the second cycle; 119 (41.5%) had follow-up histology. The rate of non-diagnostic samples (Thy1/1c) decreased from 39.6% to 30.0%. The PPV for malignant neoplastic lesions was Thy1/1c 2.6%, Thy2/2c 0.0%, Thy3a 40.0%, Thy3f 19.4%, Thy4 75.0%, Thy5 100.0% (first cycle); Thy1/1c 4.7%, Thy2/2c 0.7%, Thy3a 13.3%, Thy3f, 7.7%, Thy4, 50.0%, Thy5 100.0% (second cycle). Our department was able to reduce the rate of non-diagnostic FNAC samples and improve the diagnostic accuracy of FNAC. Auditing local outcomes helps refine and improve the reporting process. Review of false positive and false negative cases helps examine potential pitfalls of cytology.

Combination of contrast-enhanced ultrasound and strain elastography to assess cytologically non-diagnostic thyroid nodules.

The aim of the present study was to investigate the benefits of combining contrast-enhanced ultrasound (CEUS) and strain elastography (SE) for the diagnosis of thyroid nodules with non-diagnostic fine-needle aspiration cytology (FNAC) results. Between October 2013 and March 2017, CEUS and SE were performed in 226 patients (236 thyroid nodules) with non-diagnostic FNAC results prior to thyroidectomy. The diagnostic value of CEUS, SE and their combination (CEUS+SE) in distinguishing malignant from benign thyroid nodules was evaluated, using surgical pathology as a reference. Receiver operating characteristic curve analysis was used to assess the diagnostic performance of CEUS, SE and CEUS+SE in determining malignant thyroid nodules. Subsequently, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of CEUS, SE and CEUS + SE were calculated. The malignancy rate in patients with thyroid nodules and non-diagnostic FNAC results was 26.3% in the present study. The sensitivity, specificity, PPV, NPV, accuracy and area under the curve in predicting malignant thyroid nodules were 80.6, 85.6, 66.7, 92.5, 84.3 and 0.831%, respectively, using SE alone; 59.7, 95.9, 84.1, 86.9, 86.4 and 0.778%, respectively, using CEUS alone; and 83.9, 89.1, 73.6, 94.5, 88.1 and 0.865%, respectively, using the combination of CEUS and SE. Overall, the combination of CEUS with SE resulted in higher sensitivity, NPV and accuracy in the diagnosis of cytologically non-diagnostic thyroid nodules compared with CEUS or SE alone.

Accuracy of ultrasonography-guided fine needle aspiration cytology and significance of non-diagnostic cytology in the preoperative detection of thyroid malignancy.

Thyroid fine-needle aspiration cytology (FNAC) is an established investigation for the preoperative evaluation of thyroid nodules and is often done under ultrasonography guidance. While its accuracy has been widely reported, there is little evidence in the literature on the approach to non-diagnostic cytology results. In our study, we aimed to determine the diagnostic performance of ultrasonography-guided thyroid FNAC for the preoperative diagnosis of thyroid cancer at our institution and evaluate the significance of a non-diagnostic thyroid FNAC. We retrospectively reviewed the thyroid ultrasonography studies and medical records of all patients who underwent both thyroid FNAC and subsequent thyroid surgery at our institution from 2011 to 2013. FNAC results were correlated with the final histological diagnosis from surgery and the ultrasonography studies were reviewed for suspicious sonographic features. FNAC predicted malignancy with sensitivity, specificity, positive predictive value, negative predictive value, false positive rate, false negative rate and total accuracy of 90.7%, 53.6%, 43.3%, 93.7%, 46.4%, 9.3% and 64.1%, respectively. We found that only one of 26 nodules with non-diagnostic FNAC results was proven malignant on a second FNAC and subsequent thyroidectomy. The accuracy of ultrasonography-guided FNAC at our institution was comparable to that reported in the literature. There appears to be very low probability of malignancy in sonographically benign nodules with initial non-diagnostic FNAC results.

Investigation of the utility of lymph node fine-needle aspiration cytology for the staging of malignant solid tumors in dogs.

Fine-needle aspiration cytology (FNAC) of lymph nodes (LNs) is routinely used for staging canine malignant solid tumors, but studies evaluating its efficacy are limited. The primary objectives of this study were to evaluate the sensitivity/specificity of FNAC and the significance of nondiagnostic FNAC when staging canine malignant tumors. A secondary objective was to determine the prevalence of multiple nodal metastases. Lymph nodes draining malignant solid tumors assessed with FNAC and histopathology were included. The sensitivity/specificity of FNAC was determined for LNs with diagnostic FNAC, using histopathology as the gold standard. The proportion of nondiagnostic FNAC and associated histopathologic prevalence of metastasis were determined. Among the tumors with multiple LNs assessed, the prevalence of multiple nodal metastases was determined. The sensitivity of FNAC (194 LNs) was 67% for sarcomas, 100% for carcinomas, 63% for melanomas, 75% for mast cell tumors, and 100% for other round cell tumors. The specificity varied between 83% and 96%. Nondiagnostic FNAC was reported in 25% of LNs sampled (65/259), most of which were nonenlarged and/or difficult to access, and 20% of which were metastatic on histopathology. When several LNs were assessed (88/189 tumors), the prevalence of multiple nodal metastases was 24%. Histopathologic LN evaluation cannot be robustly substituted with FNAC when staging selected canine solid tumors. When a diagnostic FNAC is elusive, the histopathologic assessment remains ideal. Finally, staging should not always be limited to the assessment of a single LN.

Role of endoscopic ultrasound in undiagnosed pleural effusion

Background and Objectives:Thoracocentesis is the first diagnostic procedure for pleural effusion (PE). If diagnosis after thoracocentesis remains uncertain, pleural biopsy either computed tomography (CT)/ultrasonography (USG)-guided or thoracoscopy is required for definitive diagnosis. Overall, access to thoracoscopy is limited in many parts of the world as significant resources and expertise are required. We present the data about evaluation of undiagnosed PE by endoscopic ultrasound (EUS)-guided pleural aspiration or fine needle aspiration cytology (FNAC) of the lymph nodes/pleural deposits. This is first case series regarding EUS-guided FNAC of pleural deposits.Methods:During 2 years, 11 patients of undiagnosed PE were evaluated by EUS. Aspiration of PE was done if fluid sampling was required and EUS-FNA with rapid on-site evaluation (ROSE) was done if FNAC from PE deposit or lymph node was required.Results:Seven patients had right sided and four had left PE. Three cases had unsuccessful attempts/complications at US-guided aspiration. A single pass was successful in diagnostic aspiration in these cases and the aspirated fluid was suggestive of tuberculosis. The remaining eight cases had nondiagnostic aspiration and FNAC with ROSE (average two passes) was done from mediastinal lymphadenopathy or pleural deposits. Four cases with mediastinal lymphadenopathy had granulomatous lesions. Four cases with pleural deposits had malignancy. In this series, EUS was selected as the last diagnostic option for three indications: nontappable PE (3 cases), PE with mediastinal nodes (4 cases) and PE with pleural deposits (4 cases).Conclusion:EUS-guided imaging introduces a totally different path/technique of imaging for inspection of the pleural space. EUS-FNA can be performed as safe procedure in undiagnosed PE. At present, it appears that EUS-guided evaluation is an alternative modality for the evaluation of undiagnosed PE, in the cases who are unfit for thoracoscopy and as an alternative or adjunct to USG/CT-guided aspiration or biopsy.

Same-Day Fine-Needle Aspiration Cytology Diagnosis for Thyroid Nodules Achieves Rapid Anxiety Decrease and High Diagnostic Accuracy

The time between the moment of referral for the diagnostic workup for thyroid nodules and the outcome can be worrisome for patients. In general, patients experience high levels of anxiety during the evaluation of a lesion suspicious for cancer. Therefore, the implementation of same-day fine-needle aspiration cytology (FNAC) diagnosis is becoming standard-of-care for many solid tumors. Our aim was to assess the feasibility of same-day FNAC diagnosis for thyroid nodules and to assess patient anxiety during the diagnostic process. For feasibility of same-day FNAC diagnosis, we assessed the proportion of patients receiving a diagnosis at the end of the visit. Accuracy was measured by comparing histology with the FNAC result. Patient anxiety was measured by the State Trait Anxiety Inventory at 6 moments during the diagnostic workup. Of the 131 included patients, 112 (86%) were female, and the mean age was 53 years. All patients, except those with a nondiagnostic FNAC result (n = 26; 20%), had a diagnosis at the end of the day. There were only two discordant results. Anxiety levels at the beginning of the day were high throughout the group, State Trait Anxiety Inventory (STAI) score 43.1 (SD 2.0) and decreased significantly more in patients with a benign FNAC result (STAI score 30.2), compared to patients with a malignant or indeterminate result (STAI score 39.6). Distress of patients with a thyroid nodule undergoing same-day FNAC diagnostics was high. Same-day FNAC diagnosis is feasible and accurate for the evaluation of thyroid nodules. Therefore, same-day FNAC diagnosis seems a safer, more patient-friendly approach to diagnose thyroid nodules.

Evaluation: Fine Needle Aspiration Cytology, Ultrasound-Guided Core Biopsy and Open Biopsy Techniques.

The optimum technique for biopsy assessment of the nature of a major salivary gland mass remains controversial. Fine needle aspiration cytology (FNAC) has been the traditional and popular choice, but sampling of cellular clusters is largely associated with high non-diagnostic and false-negative rates, even under optimised circumstances. Ultrasound-guided core biopsy (USCB) provides a core of tissue that allows preservation of tissue architecture and that can be histologically and immunohistochemically examined, thereby improving the chances of a meaningful diagnosis. Although relatively recently applied in the pre-operative investigation of salivary lesions, USCB shows higher levels of accuracy and reduced non-diagnostic rates when compared with FNAC, in addition to good patient tolerability. A degree of caution should, however, be exercised because of the potential for tumour seeding, and time delays inherent to histological processing are also unavoidable. Where available, USCB may be given preference as the biopsy technique of choice in major salivary gland diagnosis. In units where FNAC performs well, USCB can be utilised when FNAC is non-diagnostic or equivocal. Intra-operative frozen section collection is invasive but may offer a secondary option in cases of non-diagnostic FNAC and/or USCB or when USCB is not available.

Thyroid Imaging Reporting and Data System and Ultrasound Elastography: Diagnostic Accuracy as a Tool in Recommending Repeat Fine-Needle Aspiration for Solid Thyroid Nodules with Non-Diagnostic Fine-Needle Aspiration Cytology

The Thyroid Imaging Reporting and Data System (TIRADS) has been found to be accurate in the stratification of malignancy risk, and elastography has been found to have a high negative predictive value in non-diagnostic thyroid nodules. Through assessment of 104 solid non-diagnostic thyroid nodules, this study investigated the role of both in recommending repeat ultrasonography-guided fine-needle aspiration for solid thyroid nodules with non-diagnostic cytology. All nodules were classified by TIRADS (categories 4a, 4b, 4c and 5), and elastography scores were assigned according to the Rago and Asteria criteria. The malignancy risks for TIRADS categories 4a, 4b, 4c and 5 were 12.5%, 25.0%, 25.8% and 16.7%, respectively. Elastography revealed the highest diagnostic performance for TIRADS category 4a, with a sensitivity, specificity, negative predictive value, positive predictive value and accuracy of 100%, 85.7%, 100%, 50% and 87.5% for the Asteria criteria. Observation may be considered for non-diagnostic solid nodules that have no other suspicious ultrasonographic features and are also benign on real-time strain elastography using the Asteria criteria.

Role of frozen section analysis in nodular thyroid pathology

IntroductionFrozen section (FS) analysis used to be the principal examination guiding surgical strategy. The development and recent standardization of fine-needle aspiration cytology (FNAC) challenges it as a systematic attitude. The present study assessed the current contribution of FS, comparing it with FNAC as a diagnostic tool guiding surgery. Material and methodsA retrospective diagnostic study analyzed 1515 thyroid samples over a 6-year period. Two hundred and fifty-two of the patients had undergone both FNAC (analyzed in our unit) and FS, revealing 69 cancers. ResultsThe sensitivity and specificity of FS and FNAC were 75.36% and 100% versus 31.88% and 100%, respectively. In case of malignancy on FNAC (22 patients), FS did not influence indications for surgery. In case of non-malignant FNAC findings, FS diagnosed cancer in 13% of cases (30/230). In the subgroup of follicular lesions (Bethesda 3 and 4), FS modified surgical strategy in only 6.2% of cases (6/97), but diagnosed 13 of the 16 cancers (81.25%) in case of Bethesda 5 on FNAC (21 cases) and in 9 of the 13 cancers (69%) associated with non-diagnostic FNAC results (Bethesda 1: 70 cases). ConclusionAlthough its contribution is small, FS optimizes surgery in certain cases. Systematic implementation may be economically justified, especially in follicular lesions diagnosed on FNAC, improving interpretation of a difficult and operator-dependent test, as is essential in certain FNAC results.

Analysis of Nondiagnostic Results in a Large Series of Thyroid Fine-Needle Aspiration Cytology Performed over 9 Years in a Single Center

Objective: Thyroid fine-needle aspiration cytology (FNAC) is the most valuable, cost-effective and accurate method for the evaluation of patients with thyroid nodules. One of its limitations is that up to 20% of results are nondiagnostic or unsatisfactory. The aim of this study was to analyze the number of thyroid FNAC specimens with nondiagnostic results obtained on an outpatient basis and how many of these had to be repeated according to their results. Study Design: This was a retrospective analysis of diagnostic reports of nondiagnostic thyroid FNAC specimens obtained between 1 January 2004 and 31 December 2012 which were retrieved by means of a computerized search. The FNAC results and the age and sex of the patients were collected. Results: From a total of 15,292 thyroid FNAC specimens, 6.8% (n = 1,033) corresponded to nondiagnostic cases. Eligible diagnostic reports for analysis included 877 cases (106 were repetitions of previous nondiagnostic FNAC). After an initial nondiagnostic finding for 771 FNAC smears, 29.5% (n = 225) were repeated with the following results: 43.6% insufficient, 49.3% benign, 6.2% follicular neoplasm, 0.4% suspicious for malignancy and 0.4% malignant. Twenty-two patients underwent a second repeated FNAC. Here the findings were: 36.4% insufficient, 59.1% benign, 4.5% follicular neoplasm, 0.0% suspicious for malignancy and 0.0% malignant. Conclusions: There was a low rate of repeated FNAC among the group of nondiagnostic cases. With repeated FNAC, the rate of nondiagnostic cases and the number of results that potentially demand surgery diminish.

Clinical Outcomes in Patients with Non-Diagnostic Thyroid Fine Needle Aspiration Cytology: Usefulness of the Thyroid Core Needle Biopsy

Patients with non-diagnostic thyroid fine needle aspiration cytology (FNAC) results undergo repeat FNAC or core needle biopsy (CNB) for definite diagnosis or surgical resection, or are followed up by clinical and ultrasound surveillance. We aimed at evaluating the risk of malignancy in patients with non-diagnostic FNACs and their clinical outcomes according to the follow-up modality. We retrospectively reviewed 1,496 (8.8%) cases with a non-diagnostic result on a first aspiration among 17,045 thyroid FNACs performed between October 2008 and August 2012. Of the non-diagnostic FNACs, 389 patients underwent a second FNAC; 125, CNB; and 89, thyroidectomy by clinical indication. The remaining patients were clinically followed up. The rate of a second non-diagnostic result was significantly higher on repeat FNAC than on CNB (33.2 vs. 2.4%; p<0.001). There was no significant difference in the malignancy risk among patients initially non-diagnostic, twice non-diagnostic, and thrice or more non-diagnostic, nor did this differ from the rate following CNB. No further malignancy was found in cases with ≥2 non-diagnostic CNBs. The malignancy risk was 51% in those who underwent thyroidectomy. The sensitivity for detecting malignancy was 65and 70% for repeat FNACs and first CNBs, respectively, with no false positives seen in either test. Approximately one-third of repeat FNACs after an initial non-diagnostic aspirate are non-diagnostic on repeat examination, and the malignancy risk may not reduce following repetitively non-diagnostic FNACs. However, a single CNB may be enough to exclude malignancy risk for patients with a non-diagnostic aspirate.

Fine‐Needle Aspiration Cytology of Thyroid Gland: A Cytology/Histology Correlation Study in Northern Ireland

Objectives: Fine needle aspiration cytology (FNAC) is a well-established preoperative investigation of thyroid nodules. British-Thyroid-Association (BTA) guidance recommends thyroid cytology reporting with “Thy” classification (Thy1 (non-diagnostic), Thy2 (benign), Thy3 (indeterminate), Thy4 (suspicious), Thy5 (malignant)). Our aim was to correlate the thyroid FNAC results with final histo-pathological diagnosis in patients undergoing thyroidectomy. Methods: Retrospective case-note analysis of 190 consecutive patients who underwent thyroid operations from 2009 to 2012. Most had ultrasound-guided-FNA (USgFNA) by an experienced radiologist. Patient demographics, FNAC results, ultrasound reports, and final histo-pathological diagnoses were analyzed. Results: Mean age was 50 (range 14-87). Male:Female was 1:5 (36:154). Sixty-one percent (115/190) had hemi-thyroidectomy. Thirty-nine percent (75/190) had total/completion thyroidectomy. Twenty-four percent (45/190) had diagnosis of thyroid cancer. Preoperative FNAC showed Thy1-9% (17), Thy2-16% (30), Thy3-55% (105), Thy4-8% (15), and Thy5-3% (5). No FNAC was carried out in 9% (18) (4 had surgery for refractory Graves, and 14 had surgery for massive retro-sternal-goiter). Postoperative histopathology results correlated correctly in 80% of Thy4 and Thy5 (4/5 with Thy5 and 12/14 with Thy4 had thyroid malignancy (9-PTC, 5-follicular, 2-anaplastic)). In the Thy3 category, 21% had thyroid cancer (11-PTC, 7-Follicular, 3-undifferentiated), 35% had multi-nodular goiter, and 25% had adenoma. Twenty-nine percent (5/17) of Thy1 and 3% (1/20) who had surgery for suspicious clinical/ultrasound features also had cancer. Conclusions: USgFNA offers a very sensitive and accurate method in detecting malignancy (&gt;80% both in Thy5 and Thy4 and &gt;29% in Thy3 lesions). Our study demonstrated &gt;29% of patients with non-diagnostic FNAC (Thy1) with suspicious clinical or radiological features had thyroid malignancy, and we recommend diagnostic hemi-thyroidectomy in this subgroup.

Malignancy Risk Analysis in Patients with Inadequate Fine Needle Aspiration Cytology (FNAC) of the Thyroid

BackgroundThyroid fine needle aspiration cytology (FNAC) is the standard diagnostic modality for thyroid nodules. However, it has limitations among which is the incidence of non-diagnostic results (Thy1). Management of cases with repeatedly non-diagnostic FNAC ranges from simple observation to surgical intervention. We aim to evaluate the incidence of malignancy in non-diagnostic FNAC, and the success rate of repeated FNAC. We also aim to evaluate risk factors for malignancy in patients with non-diagnostic FNAC.Materials and MethodsRetrospective analyses of consecutive cases with thyroid non diagnostic FNAC results were included.ResultsOut of total 1657 thyroid FNAC done during the study period, there were 264 (15.9%) non-diagnostic FNAC on the first attempt. On repeating those, the rate of a non-diagnostic result on second FNAC was 61.8% and on third FNAC was 47.2%. The overall malignancy rate in Thy1 FNAC was 4.5% (42% papillary, 42% follicular and 8% anaplastic), and the yield of malignancy decreased considerably with successive non-diagnostic FNAC. Ultrasound guidance by an experienced head neck radiologist produced the lowest non-diagnostic rate (38%) on repetition compared to US guidance by a generalist radiologist (65%) and by non US guidance (90%).ConclusionsThere is a low risk of malignancy in patients with a non-diagnostic FNAC result, commensurate to the risk of any nodule. The yield of malignancy decreased considerably with successive non-diagnostic FNAC.

Initially non-diagnostic ultrasound-guided fine needle aspiration cytology of thyroid nodules: value and management

Ultrasound (US)-guided fine needle aspiration cytology (FNAC) is an accurate, reliable, and simple method to identify a thyroid nodule as benign or malignant. However, non-diagnostic cytology results for thyroid nodules are a major limitation of US-guided FNAC. To investigate the incidence of thyroid cancer among cases with non-diagnostic results on FNAC and to provide suggestions for the management of thyroid nodules that are initially non-diagnostic by FNAC according to ultrasonographic findings. From July 2006 to December 2009, 10,317 thyroid nodules in 6684 consecutive patients underwent US-guided FNAC at our institute. Among these, 871 thyroid nodules (8.4%) were diagnosed as non-diagnostic on initial cytologic evaluation and 196 underwent a second or third FNAC. Twenty-seven thyroid nodules (18.9%) underwent surgery, while 116 thyroid nodules were cytologically confirmed as benign with no remarkable change on follow-up US were included. We retrospectively reviewed the US findings for a total of 143 thyroid nodules (123 benign nodules and 20 malignant nodules). The US features that we compared included composition, echogenicity, margin, calcifications, shape, and underlying echogenicity. In total, thyroid cancer was diagnosed in 20 nodules (14.0%). The size of the nodule was significantly associated with malignancy (P < 0.05). Most of the sonographically probable benign nodules were found to be benign (97.6%). Suspicious nodules on US were thyroid cancer in 43.2% of cases. Marked hypoechogenicity, microlobulated or irregular margin, microcalcifications, and taller-than-wide shape were significant US findings that correlated with malignancy (P < 0.05). The diagnostic performance of ultrasound for initially non-diagnostic thyroid nodules was as follows: sensitivity of 90.0%, specificity of 65.0%, positive predictive value of 29.5%, and negative predictive value of 97.6%. In terms of management of thyroid nodules with non-diagnostic FNAC cytology, US evaluation is a feasible and useful method for predicting malignancy.

Prognostic factors and follow-up of patients with differentiated thyroid carcinoma with false negative or nondiagnostic FNAC before surgery. Comparison with a control group

Since the clinical implementation of fine needle aspiration cytology (FNAC) to diagnose thyroid carcinoma, few patients remain misdiagnosed and little is known about their clinical outcomes. An observational retrospective study was carried out to analyse prognostic factors and follow-up of patients with differentiated thyroid carcinoma (DTC) not disclosed by FNAC before surgery, compared to a control group. From October 2003 to July 2010, 308 patients underwent surgery as treatment for nodular goitre and 53 had DTC. Cases were 12 subjects with DTC and benign (n=7) or nondiagnostic (n=5) FNAC. Controls were 39 subjects with DTC and suspicious (n=19) or malignant (n=20) FNAC. Prognostic factors, recurrence and survival rates were compared. Cases had longer time from FNAC to surgery than the control group (86.8±74.1 vs. 16.4±23.8weeks; P<0.001), higher prevalence of follicular carcinoma (33.3 vs. 2.6%; P=0.009), and of two-time total thyroidectomy (75 vs. 30.8%; P=0.016). Average follow-up was 42.7±25.3months (2-86months). There were no deaths. Disease-free survival for cases was 66.9±5.8months, and for controls 78.7±3.9months (P: ns). In patients with DTC, the result of the FNAC performed before surgery was not an independent predictor of recurrences or mortality in the first 7years of follow-up. Thus, false negative or nondiagnostic FNAC in a patient with DTC does not seem to be a primary prognostic factor, but it may reveal other adverse prognostic factors such as longer time to therapy and higher prevalence of follicular carcinoma that may influence long-term outcomes.