An updated audit of fine needle aspiration cytology procedure of solitary thyroid nodule

A comparative study between conventional and the Bethesda System for Reporting Thyroid Cytology of 240 cases

Introduction

Thyroid nodule is a common disorder of thyroid. Despite their benign nature, they can be associated with multiple pathologic conditions including thyroid cancer. Fine-needle aspiration plays an essential role in evaluating thyroid nodules. The Bethesda System for Reporting Thyroid Cytology (TBSRTC) has attempted to standardize reporting and cytological criteria in aspiration smears.

Aim

The aim of this study is to compare the conventional and TBSRTC and to compare and correlate the cases with histological findings wherever available.

Materials and Methods

The present study was a retrospective study undertaken in the department of pathology from January 2018 to December 2018 to access the validity of TBSRTC considering histopathology as the gold standard. May Grünwald Giemsa and Papanicolaou stained thyroid FNA smears of 240 patients were collected which were reported by the conventional system for reporting thyroid cytology and also categorized as per current Bethesda nomenclature for thyroid cytology. Diagnosis of both the reporting systems was then compared and correlated with the histological diagnosis wherever possible.

Results

A total of 240 cases were examined on cytology, out of which histopathological correlation was possible in 110 cases. For benign thyroid lesions, sensitivity and specificity with conventional system were 69.91% and 40.25%, respectively, while with TBSRTC, sensitivity and specificity were 84.04% and 29.94%, respectively. Sensitivity and specificity of conventional system for malignant thyroid lesions were 58.56% and 69.91%, respectively, while with TBSRTC, sensitivity and specificity were 73.69% and 95.12%, respectively. The Bethesda system found to be highly sensitive for benign thyroid lesions and highly specific for malignant thyroid lesions as compared to the conventional method of reporting of thyroid cytology.

Conclusion

Bethesda system was found to be superior for reporting thyroid cytology over the conventional system of reporting for thyroid cytology.

Not All Bethesda 1 Thyroid Nodules Were Created Equal: Different B1 Subgroups

OBJECTIVE

The Bethesda System for Reporting Thyroid Cytopathology is a uniform method used worldwide to report thyroid fine-needle aspiration (FNA) outcomes. This study focuses on the Nondiagnostic/Unsatisfactory category, designated as Bethesda1 (B1). The documented risk of malignancy for B1 nodules can vary significantly, implying this category is not homogenous and might be composed of different subtypes. Our hypothesis was that B1 subgroups (blood only, insufficient thyrocytes, cyst content) will vary in their malignancy rate.

METHODS

The study design was observational and retrospective. The study population included 154 patients in the Galilee Medical Center who underwent FNA examination of the thyroid gland from 2013-2018 and had a B1 result. We looked at the final diagnosis of malignant or benign for patients who underwent surgery and calculated the malignancy rate for each subgroup.

RESULTS

Malignancy rates were higher in the Blood subgroup than in the other subgroups, and higher in the Thyrocytes subgroup than in the Cyst subgroup (P < .05). All malignancies were papillary thyroid carcinomas. There was no significant difference in the malignancy rate when we further divided the B1 samples into 2 groups based on the presence of epithelial cells. Many repeat FNA tests resulted in a different B1 subgroup.

CONCLUSION

The different malignancy rates suggest that individual management approaches should be considered for each B1 subgroup.

Positive central lymph-nodes are underdiagnosed in patients with Bethesda V cytology in an endemic goiter region

Background

Fine needle aspiration (FNA) is a significant diagnostic procedure for detecting malignancy in patients with nodular thyroid disease. A high proportion of patients with cytological diagnosed follicular neoplasia (Bethesda IV and V) ultimately have thyroid cancer. The aim of this study was to evaluate the incidence of preoperatively undiagnosed central lymph node metastasis in patients with multinodular goiter (MNG).

Methods

Patients who underwent FNA and were classified as Bethesda IV/V were included. Applying a radical approach, all patients underwent (hemi)thyroidectomy and prophylactic unilateral central neck dissection.

Results

During our study period 2009-2013, 60 patients (19.7%) were classified as Bethesda IV and 21 (6.9%) Bethesda V. Final histopathological results revealed malignancy in 35 (43.2%) of 81 Bethesda IV/V nodules. Of the nodules classified as Bethesda IV, 20 (33.3%) showed malignancy in the final histology. Ten patients (16.7%) had papillary micro-carcinoma (mPTC, <10 mm), 4 (6.6%) PTC and 6 (10%) follicular thyroid cancer. Fifteen of 21 (71.4%) Bethesda V nodules were revealed as PTC of whom seven (33.3%) patients also had lymph-node metastases.

Conclusions

While 33.3% of the patients with PTC, preoperatively classified as Bethesda V, had previously undetected positive lymph-nodes, only one patient with Bethesda IV had lymph-node metastasis.

Impact of ultrasonographic features, cytomorphology and mutational testing on malignant and indeterminate thyroid nodules on diagnostic accuracy of fine needle cytology samples: A prospective analysis of 141 patients

OBJECTIVE

Fine needle cytology (FNC) is the first-line diagnostic method to determine the benign or malignant nature of thyroid nodules. The gray zone of cytological classifications remains, however, a crucial and challenging area for cytopathologists.

DESIGN, PATIENTS AND MEASUREMENTS

In the present study, 141 thyroid cytological samples, with ultrasonographic suspicious features, have been prospectively analysed. Molecular analyses were performed by an innovative technology using two multiplex PCRs for the amplification of BRAF, N-H-K-RAS and RET exon genes. RNA samples were studied for RET/PTC1 and RET/PTC3 rearrangements by PCR amplification, and the conditions were set-up to study, with a single experiment, both wild-type PAX8 and PAX8/PPARɣ rearrangements. In total, 111 samples were examined for BRAF, N-H-KRAS and RET genes. An ultrasonographic, cytological and molecular correlation was also carried out in an attempt to suggest a possible way to manage the patients with thyroid nodules. Cyto-histological correlation was available in 115 cases, and it was used to verify the global diagnostic accuracy of this combined approach.

RESULTS

According to the histopathological diagnosis, FNC accuracy was 100% for TIR5 and metastases; 89% for TIR4; 84% for TIR3A and 58% for TIR3B. About 11% of the studied samples showed either RET-PTC1 or RET/PTC3 chromosomal rearrangements, and only one sample simultaneously presented RET/PTC1 and RET/PTC3 rearrangements. PAX8/PPARɣ rearrangement was found in 6% of the samples.

CONCLUSIONS

A multidisciplinary approach to the thyroid is therefore necessary to develop innovative methods suitable for an improved diagnostic and prognostic definition of thyroid cancer.

Interaction among susceptibility genotypes of PARP1 SNPs in thyroid carcinoma

Polymorphisms in DNA repair genes may alter the repair mechanism which makes the person susceptible to DNA damage. Polymorphic variants in these DNA repair pathway genes such as Poly (ADP-ribose) polymerase- 1 (PARP1) have been associated with susceptibility of several types of cancer including thyroid. Many studies have been published on PARP1 gene polymorphisms and carcinogenesis with inconsistent results. The present study was designed to explore the link between the PARP1 polymorphisms and thyroid cancer risk. This case-control study was comprised of 456 thyroid cancer patients and 400 healthy controls. Three SNPs of PARP1 gene; rs1136410, rs1805414 and rs1805404 were analyzed using ARMS-PCR. The combined genotype and haplotype analysis were performed using haploview software 4.2. Major allele homozygote (CC) of rs1136410 and combined genotype (TT+TC) of rs180414 showed a significant association with thyroid cancer risk (OR = 1.30; 95% CI 0.99–1.77; P = 0.05) and (OR = 0.43; 95% CI = 0.27–0.67; P = 0.03). Histological subtype analysis showed the significant association of selected PARP1 SNPs with papillary, follicular and anaplastic subtypes in thyroid cancer patients. Haplotype analysis showed that TCT (p = 0.01), CTT (p = 0.02) and CTC (p = 0.03) were significantly higher in controls when compared to cases. However, TTC (p = 0.05) and TCC (p = 0.01) haplotype frequency was significantly higher in cases compared to controls. Global haplotype analysis showed that there was an overall significant difference between cases and controls (p = 0.001). Identification of these genetic risk markers may provide evidence for exploring insight into mechanisms of pathogenesis and subsequently aid in developing novel therapeutic strategies for thyroid cancer.

Upregulation of RAD51 expression is associated with progression of thyroid carcinoma

AIMS

RAD51 participates in homologous recombination repair (HRR) of double-stranded DNA breaks (DSBs) which may cause genomic instability and cancer. The aim of this study was to investigate RAD51 gene expression at transcriptional and translational levels to measure mRNA and protein level and to correlate its relationship with proliferation marker, Ki67 in thyroid cancer patients. This study also explored correlation of these genes with different clinicopathological parameters of the study cohort by Spearman's rank correlation coefficient.

METHODS

Quantitative real time polymerase chain reaction (qRT-PCR) and immunohistochemistry were used to detect mRNA transcript levels and protein expression of RAD51 and Ki67 in 102 cases of thyroid cancer tissues and equal number of uninvolved healthy thyroid tissue controls.

RESULTS

Data showed that expression for both RAD51 and Ki67 was significantly increased in thyroid cancer (p<0.001). High RAD51 and Ki67 expression was associated with later stages, poor tissue differentiation, large tumor size, positive lymph node metastasis and distant metastasis. The correlation analysis demonstrated a strong positive correlation (r=0.461) between RAD51 and Ki67 on mRNA level and on protein level (r=0.866). Strong correlation was observed between clinicopathological characteristics and selected molecules.

CONCLUSION

The present study concluded that upregulation of RAD51 and overexpression of Ki67 may be associated with the progression of thyroid cancer.

Cytopathologic diagnosis of fine needle aspiration biopsies of thyroid nodules

Fine-needle aspiration (FNA) cytology is an important diagnostic tool in patients with thyroid lesions. Several systems have been proposed for the cyropathologic diagnosis of the thyroid nodules. However cases with indeterminate cytological findings still remain a matter of debate. In this review we analyze all literature regarding Thyroid Cytopathology Reporting systems trying to identify the most suitable methodology to use in clinical practice for the preoperative diagnosis of thyroid nodules. A review of the English literature was conducted, and data were analyzed and summarized and integrated from the authors’ perspective. The main purpose of thyroid FNA is to identify patients with higher risk for malignancy, and to prevent unnecessary surgeries for benign conditions. The Bethesda System for Reporting Thyroid Cytopathology is the most widely used system for the diagnosis of thyroid FNA specimens. This system also contains guidelines for the diagnosis and treatment of indeterminate or suspicious for malignancy cases. In conclusion, patients who require repeated FNAs for indeterminate diagnoses will be resolved by repeat FNA in a percentage of 72%-80%.

Comparison of pre-operation diagnosis of thyroid cancer with fine needle aspiration and core-needle biopsy: a meta-analysis

BACKGROUND

The aim of this meta-analysis was to compare sensitivities and specificities of fine needle aspiration (FNA) and core needle biopsy (CNB) in the diagnosis of thyroid cancer.

MATERIALS AND METHODS

Articles were screened in Medline, the Cochrane Library, EMBASE and Google Scholar, and subsequently included and excluded based on the patient/problem-intervention-comparison-outcome (PICO) principle. Primary outcome was defined in terms of diagnostic values (sensitivity and specificity) of FNA and CNB for thyroid cancer. Secondary outcome was defined as the accuracy of diagnosis. Compiled FNA and CNB results from the final studies selected as appropriate for meta-analysis were compared with cases for which final pathology diagnoses were available. Statistical analyses were performed for FNA and CNB for all of the selected studies together, and for individual studies using the leave-one-out approach.

RESULTS

Article selection and screening yielded five studies for meta-analysis, two of which were prospective and the other three retrospective, for a total of 1,264 patients. Pooled diagnostic sensitivities of FNA and CNB methods were 0.68 and 0.83, respectively, with specificities of 0.93 and 0.94. The areas under the summary ROC curves were 0.905 (± 0.030) for FNA and 0.745 (± 0.095) for CNB, with no significant difference between the two. No one study had greater influence than any other on the pooled estimates for diagnostic sensitivity and specificity.

CONCLUSIONS

FNA and CNB do not differ significantly in sensitivity and specificity for diagnosis of thyroid cancer.

Laser capture microdissection is a valuable tool in the preoperative molecular screening of follicular lesions of the thyroid: an institutional experience

OBJECTIVES

The application of molecular tests to thyroid fine needle aspiration (FNA) has been shown to be a valuable tool to better refine the pre-operative malignant risk of patients with indeterminate cytology results. In this study, we investigated the feasibility of using the laser capture microdissection (LCM) technique to obtain DNA and RNA for molecular tests in routine thyroid FNA smears.

METHODS

Nine coupled FNA and histological retrospective cases and 31 prospective FNA cases with a follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN) diagnosis were included in this study. Both cytological and histological specimens were investigated by direct sequencing and reverse transcription-polymerase chain reaction (RT-PCR) for BRAF and RAS mutations and for PAX8/PPARG and RET/PTC rearrangements, respectively.

RESULTS

LCM yielded good DNA and RNA quality in all cases (100%) in both series, irrespective of the staining used (Giemsa, Papanicolaou, immunostain for thyroglobulin) and the cytology technique (conventional or liquid-based preparations). Total mutations found in the FNA and in the corresponding histological specimen in both series were: one PAX8/PPARG rearrangement in a follicular carcinoma (FC), four NRAS mutations [in two FCs, one papillary carcinoma and one follicular adenoma (FA)] and one HRAS mutation in one FA. The sensitivity was 67% and the specificity was 91%.

CONCLUSIONS

LCM is a valuable tool to obtain good quality DNA and RNA for molecular tests in cytological material from thyroid FNA, and can be a useful option in the management of patients with an FN/SFN FNA diagnosis.

Diagnostic accuracy of Bethesda system for reporting thyroid cytopathology: an institutional perspective

Introduction

Thyroid swelling is common problem among South Asian women. Although benign nodules far outnumber cancerous lesions, the risk of malignancy needs to be evaluated preoperatively for which fine needle aspiration cytology (FNAC) is widely used. Bethesda system for reporting thyroid cytopathology (BSRTC) was introduced to streamline the reporting of thyroid aspirates. We aimed to evaluate the disease spectrum of thyroid cytopathology and correlation of BSRTC with final histopathology in our setup.

Methods

The study was conducted at Histopathology department of Liaquat National Hospital, Karachi, involving 528 patients with thyroid swelling who underwent FNAC. Out of these 528 cases, 61 patients subsequently underwent surgical excision. Results of final histopathology were correlated with cytologic diagnosis.

Results

Mean age of the patients included in the study was 39.7 ± 13(14–84) and male to female ratio was 1:3.6. Out of total 528 cases, 403 cases were diagnosed as benign (Bethesda 2) and 67 were Bethesda 3 (follicular lesion of undetermined significance, FLUS) while 22 cases were categorized as either malignant or suspicious for malignancy (Bethesda 6 and 5). Histopathologic correlation was done in 61 cases. For Bethesda 5 and 6 categories, 100% concordance was found, however for Bethesda 2 category, 5 out of 45 cases were found to have malignant diagnosis on final histopathology. The incidence of malignancy in Bethesda categories 2 through 4 were 11.1%, 33.4%, 25%, 100% and 100% respectively. Overall accuracy of FNA cytology was 80.3% with 64.3% sensitivity and 85.1% specificity.

Conclusion

Our study validated the accuracy of BSRTC in our setup. Therefore we recommend routine use of BSRTC for reporting thyroid cytopathology for initial workup of patients with thyroid nodule. However, risk of malignancy was found to be significantly high in Bethesda 3 category to warrant further workup including ultrasound/thyroid scan in addition to repeat FNAC.

Clinical audit of repeat fine needle aspiration in a general cytopathology service

Background:

The few studies on repeat aspiration focussed on accuracy of diagnosis following repeat. Numbers and documented reasons for repeat remain unaddressed.

Aim:

To study factors associated with requests for repeat fine needle aspiration cytology (FNAC).

Settings and Design:

Metropolitan hospital, clinical audit.

Materials and Methods:

Audit of 5104 FNAC in 10 months.

Statistical Analysis Used:

Univariate, and multivariate binary logistic regression.

Results:

Seven hundred and six patients (13.8%) were advised repeat aspirates. Three hundred and twelve of these were actually repeated (44.1%). Carryover of actually repeated aspirates to subsequent months averaged 10.8 (34.2%). Maximum numbers of repeat requests were from thyroid 76/415 (18.3%), followed by lymph node 310/1856 (16.7%), and from breast 86/716 (12.0%). Outcome of actually repeated aspirates were: Diagnostic 181/312 (58.0%), and non-diagnostic 131/312 (41.9%). Reasons for repeat were inadequate aspirates 370/706 (52.4%), non-diagnostic descriptive reports 309/706 (43.7%); in 27/706 (3.8%), no reason was mentioned.

Conclusions:

Inadequate aspirates, non-diagnostic descriptive reports, and FNAC/FNAB from thyroid, lymph nodes, and breast contribute to repeats. We suggest steps to reduce the number of repeat aspirates to eliminate extra work.

How to interpret thyroid fine-needle aspiration biopsy reports: a guide for the busy radiologist in the era of the Bethesda Classification System

OBJECTIVE

Fine-needle aspiration biopsy (FNAB) is the current primary test to risk stratify thyroid nodules. However, in up to one third of biopsies, cytology is indeterminate. The Bethesda System for Reporting Thyroid Cytopathology categorizes thyroid cytology findings into six groups, with each group assigned a putative malignancy risk. This article reviews the Bethesda System, emphasizing the key facts necessary to understand thyroid biopsy results and effectively manage patients after FNAB.

CONCLUSION

It is important to diagnose and stratify the risk of malignancy in thyroid nodules. A working knowledge of the Bethesda System permits accurate, evidence-based risk stratification of patients with thyroid nodules and thereby facilitates their management. Because it is a uniform diagnostic approach, the Bethesda System allows comparisons of different management strategies across different institutions.

Atypical squamous metaplasia in a benign cystic thyroid nodule mimicking high-grade carcinoma

Squamous metaplasia (SM) occurs in a variety of thyroid conditions, both neoplastic and non-neoplastic. In a small subset of benign thyroid lesions, SM can create a diagnostic pitfall by mimicking a malignant process. Here, we describe the case of a 52-year-old male with a 1.5 cm right thyroid nodule. Ultrasound-guided fine-needle aspiration biopsy showed markedly atypical, mitotically active epithelial cells which were suspicious for high-grade carcinoma. Resection of the nodule demonstrated a follicular adenoma with cystic changes and atypical SM of the cyst-lining component. As illustrated here, SM of the thyroid represents an important diagnostic pitfall for the cytopathologist, and should be included in the differential diagnosis of thyroid nodules, particularly those with potentially benign cystic changes.

Update in thyroid fine needle aspiration

Thyroid fine needle aspiration (FNA) is a safe, cost effective, and relatively accurate method for guiding the initial management of a thyroid nodule. The popularity of thyroid FNA is reflected in the fact that over 350,000 thyroid FNAs are performed each year in the USA. As we move into the next decade, several issues pertaining to thyroid FNA are being addressed including: how to better apply thyroid FNA as a differential test for follicular-patterned thyroid tumors, how to manage the atypical thyroid FNA, and how to use thyroid FNA in the evaluation of poorly differentiated thyroid carcinomas.

Comparison of 5-tiered and 6-tiered diagnostic systems for the reporting of thyroid cytopathology: a multi-institutional study

BACKGROUND

At present, thyroid fine-needle aspiration (FNA) specimens are diagnosed using a tiered classification scheme, with the most popular of these being the 5-tiered and 6-tiered systems. In this study, the authors present their institutional experiences using these 2 different systems and evaluate their efficacy based on the surgical follow-up.

METHODS

Thyroid FNA specimens and their corresponding surgical resection specimens were collected between 2007 and 2009. The following diagnostic categories are used in both systems: unsatisfactory/nondiagnostic, benign, follicular neoplasm/suspicious for follicular neoplasm, suspicious for malignancy, and malignant. An additional category termed atypia of undetermined significance/follicular lesion of undetermined significance was used for atypical cases in the 6-tiered system. Statistical analysis was performed by comparing the different diagnostic categories.

RESULTS

The case cohort included a total of 7686 thyroid FNA specimens representing 3962 nodules and 3724 nodules, respectively, in the 5-tiered and 6-tiered systems. Negative predictive values for the benign categories (96.9% vs 97.5%; P = 1) and positive predictive values for both the follicular neoplasm categories (26.5% vs 32.1%; P = .2531) and the malignant categories (99.1% vs 99.4%; P = 1) were similar. The most significant differences between the 5-tiered and 6-tiered systems were the percentage of cases classified as benign (83.9% vs 55.4%; P < .0001) and as follicular neoplasms (4.6% vs 23.8%; P < .0001). It is interesting to note that fewer patients were referred for surgery in the 5-tiered system compared with the 6-tiered one (9.1% vs 36.5%; P < .0001).

CONCLUSIONS

Use of either the 5-tiered or 6-tiered reporting systems for thyroid FNA specimens can potentially affect the clinical management of patients with thyroid nodules.

Comparison of fine needle aspiration cytology and thyroid scan in solitary thyroid nodule

Objective. This was a comparative study between FNAC and thyroid scan used to diagnose the solitary thyroid nodule and histopathology was used as gold standard to compare the results of both modalities. We hypothesized that Fine needle aspiration cytology and thyroid scan diagnose solitary thyroid nodule (STN) as accurately as histopathology. Materials and Methods. This study comprised of 50 patients with solitary thyroid nodules (STN) presented to OPD. After clinical examination these patients were referred to Centre for Nuclear Medicine, Mayo Hospital Lahore for thyroid function tests and thyroid scan (TS). These patients underwent FNAC in the department of Pathology and surgery in Mayo Hospital. The cases were operated and evaluated for histopathological changes. Results. On thyroid scan, 40 patients (80%) having cold nodule were labeled as suspicious 10 patients (20%) had hot nodule. On FNAC 23 patients (46%) had benign lesion, 22 patients (44%) had indeterminate lesion and 5 patients (10%) had malignant lesions. On histopathology, 45 patients (90%) were confirmed to have benign lesions and 5 patients (10%), malignant lesions. After comparison of results of thyroid scan and FNAC with histopathology, the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of thyroid scan were 80%, 20%, 10%, 90% and 26%, respectively whereas those of FNAC were 80%, 97.7%, 80%, 97.7% and 96%, respectively. Conclusion. Fine needle aspiration was a significantly better predictor of malignancy than thyroid scan and resulted in a smaller proportion of excisions for benign nodules.

Predictive factors related to the recurrence at US-guided fine needle aspiration in postoperative patients with differentiated thyroid cancer

OBJECTIVES

The recent American Thyroid Association management guidelines suggest cervical ultrasonography (US) surveillance in patients with differentiated thyroid cancer (DTC). This study was conducted to identify predictive factors that can determine whether subsequent fine needle aspiration guided by ultrasound (US-FNA) is indicated in patients with lesions detected by US after surgery for DTC.

DESIGN

Retrospective analysis at a university-based tertiary hospital.

PATIENTS AND MEASUREMENTS

We reviewed 207 cases of postoperative US-FNA in 180 patients diagnosed with DTC. We examined the relationship between US-FNA histology and clinical factors, imaging abnormalities found by US and with other modalities and pathological staging.

RESULTS

US-FNA recurrence was positive in 56 (27%) cases and negative in 151 (73%) cases. The mean lesion size for FNA was 0·83 cm (range 0·2-2·9 cm). Univariate analysis indicated that tumour recurrence on US-FNA is associated with elevated stimulated thyroglobulin (sTg) levels, with the initial size of the primary tumour, with abnormal US findings, including the ipsilateral site, level III or IV location and extrathyroidal extension, and with other imaging abnormalities. However, multivariate analysis revealed an independent association between recurrence on FNA and suspicious US findings (OR 9·410; 95% CI 3·322-26·654; P<0·001) and elevated serum sTg (OR 5·001; 95% CI 1·067-23·485; P =0·041). Findings on US that were discriminating for recurrent nodules at the thyroidectomy site were abnormalities that were not oval shape or which had an irregular margin. Calcifications or cystic change showed a low sensitivity of 14%.

CONCLUSIONS

US-FNA for diagnosis of recurrence after surgery for DTC may be limited to patients with elevated sTg or with lesions that have specific suspicious US findings.

Application of pattern analysis in fine needle aspiration of solitary nodule of thyroid

BACKGROUND

Various methods are used to arrive at a conclusive diagnosis of thyroid lesions on fine needle aspiration cytology (FNAC). Systemic pattern analysis is one such that can be used to analyze the lesions and divide them into individual categories.

AIMS

To study the application of pattern analysis in the interpretation of solitary thyroid nodule (STN).

MATERIALS AND METHODS

Two hundred and nineteen cases of fine needle aspiration cytology of STN were reviewed along with histopathological correlation. Smears were classified based on primary and secondary patterns. Predominant pattern (primary) was identified and lesion categorized. This was followed by identifying the next dominant pattern (secondary) and recategorization. Cytological diagnosis based on primary and secondary patterns was correlated with the histopathological diagnosis.

RESULTS

Based on pattern analysis, the study had a sensitivity of 66.7% and specificity of 98.9%. The positive predictive value and negative predictive value were 88.9% and 96% respectively and the overall diagnostic accuracy was 95.4%.

CONCLUSIONS

The present study demonstrates the feasibility and applicability of pattern analysis in diagnosing thyroid lesions by FNAC, which could be easily reproducible.

Comparison of accuracy of diagnostic modalities for evaluation of breast cancer with review of literature

This study was conducted to confirm which of these modalities [mammography (MG), fine-needle aspiration cytology (FNAC), core-needle biopsy (CNB), or intraoperative touch imprint cytology (IOTIC)] is useful to detect breast cancer and to compare the accuracy of these modalities for the diagnostic setting. One hundred seventy-five, 85, 78, and 25 patients were selected who underwent FNAC, MG, IOTIC, and CNB, respectively. Histopathology was used as a gold standard for comparison of the results of all diagnostic modalities. Twenty-five patients with combinations of three preoperative tests (MG, FNAC, CNB) showed 100% accurate results when compared with histopathology, while the overall accuracy for MG, FNAC, and CNB was 91.7%, 91.5%, and 96%, respectively. Both touch and scrape imprints' sensitivity, specificity, positive predictive value, negative predictive value (NPV), and accuracy were 100% for class V and class II smears, while sensitivity, accuracy, and NPV were 87, 95, and 83% for IOTIC and 94%, 96%, and 89% for IOSC for class III and IV smears. On comparison of the results of all these procedures, the difference was nonspecific (P = 0.2, 0.3, 0.5, 0.55, and 0.6 for MG, FNAC, IOTI, IOSC, and CNB, respectively). Combinations of preoperative tests (MG, FNAC, CNB) were more accurate, reliable, and acceptable when compared with individual diagnostic procedure, but these have their own technical limitations. The accuracy of CNB was much higher than that of MG and FNAC. IOTP and IOSC are simple and cost effective diagnostic tests with better accuracy that can be used as an alternate to frozen section in diagnostic settings and margin assessments.

How to combine ultrasound and cytological information in decision making about thyroid nodules

The purpose of this study was to evaluate the role of sonographic-cytological correlation in determining which nodules should be reaspirated to reduce the false-negative rate of fine-needle aspiration biopsy (FNAB). A retrospective cohort study was performed on a database of 568 patients with 672 focal thyroid nodules. An independent two-sample t-test was used to compare the risk of malignancy according to clinical factors. We evaluated the risk stratification of malignancy according to US groupings and cytological results. Additionally, we calculated the false-negative rate of FNAB and investigated the cytological results of repeat aspiration. The malignancy rate (92.2-98.5%) was high in thyroid nodules designated "malignant" or "suspicious for papillary carcinoma" on FNAB, regardless of US features. In contrast, when focal thyroid nodules had "benign" readings on FNAB, the malignancy rate was lower for the "probably benign" US features (2.9%) than for the suspicious nodules (56.6%). The false-negative rate of FNAB was 5.8%. Repeat aspiration revealed "suspicious for malignancy" or "malignancy" results in 15 (93.8%) of 16 thyroid cancers with "benign" results on initial aspirate. This study demonstrated repeat FNAB should be performed on focal thyroid nodules with suspicious US features even when initial FNAB results are benign.