How does one separate cellular follicular lesions of the thyroid by fine-needle aspiration biopsy?

Diagnostic accuracy of fine needle aspiration cytology in thyroid lesions

PURPOSE

Evaluation of accuracy of fine needle aspiration cytology (FNAC) in the diagnosis of different thyroid lesions.

PATIENTS AND METHODS

This is a retrospective study of 296 diagnosed cases of thyroid nodules referred to cytology unit, pathology department, NCI, who underwent FNAC for diagnosis. The results were categorized according to the recent Bethesda classification into: insufficient for diagnosis, benign, atypical follicular lesion of undetermined significance, follicular neoplasm, suspicious for malignancy, and malignant sampling. The final histologic diagnosis and/or clinico-radiologic follow-up assessment for non-neoplastic lesions were considered the gold standard.

RESULTS

The study included 296 cases presented with thyroid nodules who underwent diagnostic thyroid FNAC. Female to male ratio was 5.2:1, and the median age was 44years. Ninety-eight cases (33.1%) were diagnosed as benign, 40 cases (13.5%) as follicular lesion of undetermined significance, 49 cases (16.5%) as follicular neoplasm, 30 cases (10.1%) as suspicious for malignancy, 58 cases (19.5%) as malignant, and 21 cases (7.1%) as unsatisfactory. Nodular hyperplasia represented the majority of benign cases (89.8%), while papillary carcinoma was the most frequent malignant lesion (72.4%). Cytologic diagnoses were compared with their corresponding final histologic ones. FNAC achieved a sensitivity of 92.8, a specificity of 94.2%, a positive predictive value of 94.9%, a negative predictive value of 91.8%, a false positive rate of 7.2%, a false negative rate of 5.8%, and a total accuracy of 93.6%.

CONCLUSION

FNA cytology is a sensitive, specific, and accurate initial diagnostic test for the evaluation of patients with thyroid swellings.

c-KIT receptor expression is strictly associated with the biological behaviour of thyroid nodules

BACKGROUND

A large amount of information has been collected on the molecular tumorigenesis of thyroid cancer. A low expression of c-KIT gene has been reported during the transformation of normal thyroid epithelium to papillary carcinoma suggesting a possible role of the gene in the differentiation of thyroid tissue rather than in the proliferation. The initial presentation of thyroid carcinoma is through a nodule and the best way nowadays to evaluate it is by fine-needle aspiration (FNA). However many thyroid FNAs are not definitively benign or malignant, yielding an indeterminate or suspicious diagnosis which ranges from 10 to 25% of FNAs. BRAF mutational analysis is commonly used to assess the malignancy of thyroid nodules but unfortunately it still leaves indeterminate diagnoses. The development of molecular initial diagnostic tests for evaluating a thyroid nodule is needed in order to define optimal surgical approach for patients with uncertain diagnosis pre- and intra-operatively.

METHODS

In this study we extracted RNA from 82 FNA smears, 46 malignant and 36 benign at the histology, in order to evaluate by quantitative Real Time PCR the expression levels of c-KIT gene.

RESULTS

We have found a highly preferential decrease rather than increase in transcript of c-KIT in malignant thyroid lesions compared to the benign ones. To explore the diagnostic utility of c-KIT expression in thyroid nodules, its expression values were divided in four arbitrarily defined classes, with class I characterized by the complete silencing of the gene. Class I and IV represented the two most informative groups, with 100% of the samples found malignant or benign respectively. The molecular analysis was proven by ROC (receiver operating characteristic) analysis to be highly specific and sensitive improving the cytological diagnostic accuracy of 15%.

CONCLUSION

We propose the use of BRAF test (after uncertain cytological diagnosis) to assess the malignancy of thyroid nodules at first, then the use of the c-KIT expression to ultimately assess the diagnosis of the nodules that otherwise would remain suspicious. The c-KIT expression-based classification is highly accurate and may provide a tool to overcome the difficulties in today's preoperative diagnosis of thyroid suspicious malignancies.

Thy3 cytology: what to do next?

INTRODUCTION

Cytological analysis of thyroid fine needle aspiration (FNA) is aided by the 'Thy' classification. However, there is often confusion surrounding the management of patients with a Thy3 classification. A subdivision of Thy3 has been created to help reduce this dilemma but its use within the UK appears to by infrequent. This paper analyses the management of patients with Thy3 cytology from FNA of a thyroid nodule in a UK case series and reviews the relevant literature. It also describes the results of a survey of selected UK ENT departments on the use of the Thy3 classification and its subdivisions.

PATIENTS AND METHODS

A retrospective analysis of a case series of patients was undertaken. In addition, a telephone survey of local/regional pathology departments was conducted to assess the utilisation of the Thy classification and to assess the awareness and usage of the Thy3 subdivisions.

RESULTS

A total of 39 Thy3 results (11 males, 28 females) were identified from 2007 to 2009. Of these, 24 patients went on to have surgery, 8 had a further FNA, 2 had a Tru-cut biopsy and 5 were lost to follow-up. Eleven (28.2%) patients were subsequently diagnosed with a thyroid malignancy. The survey identified that none of the departments had adopted the Thy3 subclassifications and only 40% were aware of them.

CONCLUSIONS

Thy3 results from thyroid FNA have a significant risk of malignancy but there remains confusion surrounding their management. This district general hospital has adopted and recommends the use of the Thy3 (i) and Thy3 (ii) subdivisions in order to assist decision-making and avoid delays in treatment or unnecessary surgery.

A cell pattern approach to interpretation of fine needle aspiration cytology of thyroid lesions: A cyto-histomorphological study

Aim:

Our study aimed at a cell pattern approach to interpret thyroid cytology and to demonstrate diagnostic accuracy of fine needle aspiration cytology (FNAC) with an emphasis on diagnostic pitfalls.

Materials and Methods:

A total number of 218 goitre cases, from the year 2000 to 2004, were reviewed retrospectively from the cytology files, without considering the previous cytological diagnosis. Four cases with inadequate aspirate were excluded. The predominant cell pattern, such as macro/normofollicular, microfollicular, papillary, syncytial, dispersed and cystic pattern, was noted in each case. The final diagnosis was arrived by observing the cellular details and background elements. Cytological diagnosis was correlated with histopathology in 75 cases. The sensitivity and specificity were computed.

Results:

Normo/macrofollicular pattern was seen in 71.96% of nodular goitre and 6.9% of follicular neoplasms. Around 86.2% of follicular neoplasms and 17.6% of papillary carcinoma had microfollicular pattern. The papillary pattern was seen in 47% of papillary carcinoma. Syncytial pattern was noticed in 72.3% of chronic lymphocytic thyroiditis and 29.4% of papillary carcinoma. Cytological diagnosis was concordant with histopathological diagnosis in 65 cases. Overall sensitivity and specificity of FNAC in diagnosing neoplastic lesions of thyroid were 83.33 and 95.55%, respectively.

Conclusion:

FNAC is more sensitive and specific in triaging neoplastic from non-neoplastic thyroid lesions. Identification of the predominant cell pattern would be complementary to analysis of cell morphology and background details in cytological diagnosis of thyroid lesions. This approach helps to diagnose follicular neoplasm and follicular variant of papillary thyroid carcinoma.

Fine-needle aspiration in the work-up of thyroid nodules

Fine-needle aspiration (FNA) is the crucial diagnostic test used for the evaluation of patients with a thyroid nodule. The result of an FNA determines if a patient can be followed with repeated examinations or referred for surgery. The value of FNA can be enhanced by attention to technical details. Communication between operator and pathologist is essential. A pathologist's interpretation is aided if essential clinical information is provided on a requisition form. Although reporting terminology has been varied and confusing in the past, a proposal for a uniform reporting system provides 6 clearly defined and clinically relevant reporting categories and promises to standardize the reporting of thyroid FNA results.

The Bethesda System For Reporting Thyroid Cytopathology

To address terminology and other issues related to thyroid fine-needle aspiration (FNA), the National Cancer Institute (NCI) hosted the NCI Thyroid FNA State of the Science Conference. The conclusions regarding terminology and morphologic criteria from the NCI meeting led to the Bethesda Thyroid Atlas Project and form the framework for The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). For clarity of communication, TBSRTC recommends that each report begin with 1 of 6 general diagnostic categories. The project participants hope that the adoption of this flexible framework will facilitate communication among cytopathologists, endocrinologists, surgeons, radiologists, and other health care providers; facilitate cytologic-histologic correlation for thyroid diseases; facilitate research into the epidemiology, molecular biology, pathology, and diagnosis of thyroid diseases; and allow easy and reliable sharing of data from different laboratories for national and international collaborative studies.

The Bethesda System for Reporting Thyroid Cytopathology

OBJECTIVE

To address terminology and other issues related to thyroid fine-needle aspiration (FNA), the National Cancer Institute (NCI) hosted The NCI Thyroid FNA State of the Science Conference. The conclusions regarding terminology and morphologic criteria from the NCI meeting led to the Bethesda Thyroid Atlas Project and form the framework for the Bethesda System for Reporting Thyroid Cytopathology.

DESIGN

Participants of the Atlas Project were selected from among the committee members of the NCI FNA State of the Science Conference and other participants at the live conference. The terminology framework was based on a literature search of English language publications dating back to 1995 using PubMed as the search engine; online forum discussions ( http://thyroidfna.cancer.gov/forums/default.aspx ); and formal interdisciplinary discussions held on October 22 and 23, 2007, in Bethesda, MD.

MAIN OUTCOME

For clarity of communication, the Bethesda System for Reporting Thyroid Cytopathology recommends that each report begin with one of the six general diagnostic categories. Each of the categories has an implied cancer risk that links it to an appropriate clinical management guideline.

CONCLUSIONS

The project participants hope that the adoption of this framework will facilitate communication among cytopathologists, endocrinologists, surgeons, and radiologists; facilitate cytologic-histologic correlation for thyroid diseases; facilitate research into the understanding of thyroid diseases; and allow easy and reliable sharing of data from different laboratories for national and international collaborative studies.

Absence of microfollicular basement membrane: a new indicator in the diagnosis of follicular carcinoma thyroid

The thyroid follicles represent a biological continuum. Each follicle is closely related to the follicle that is next to it. The important feature of a follicular carcinoma is a microfollicular pattern. We report a case of follicular carcinoma in a 48-year-old female that demonstrates microfollicles which are larger in size and contain more number of follicular cells in cytologic smears (20-29 cells) in contrary to the literature definition of microfollicles containing approximately 6-12 cells. We also demonstrate absence of basement membranes in these microfollicles in histologic sections by Silver Methanamine Stain, which may be an indicator to search for vascular and capsular invasion. This case report also describes postoperative positron emission tomography scan findings.

Necrotic debris in thyroid aspirates: a feature of follicular carcinoma of the thyroid

Fine needle aspirates from 44 follicular thyroid tumours (30 adenomas, 14 carcinomas) have been studied. All aspirates contained neoplastic cells in follicular and trabecular arrangements. The individual tumour cells showed varying degrees of anisonucleosis and nuclear pleomorphism. Colloid was scanty or absent from all smears. Granular or filamentous necrotic material was observed in both biopsies and smears from one moderately and two poorly differentiated follicular carcinomas, but in none of the adenomas. This suggests that necrotic debris may be a feature of follicular carcinoma of the thyroid.

Superficial malignant neoplasms in southwestern Ethiopia: a cytopathological approach

The aim of this study was to describe the distributions of superficial malignant neoplasms diagnosed by fine-needle aspiration cytology (FNAC). A prospective cross-sectional study was conducted within the Jimma Teaching Hospital, Pathology Department, Jimma University during the years between September 1998 and August 2002. Cases fulfilling cytopathological evidences of superficial malignancies were included whereas deep-seated malignancies were excluded from the study. An air-dried smear stained with the Wright staining procedure was utilized for the FNAC diagnostic technique. A total of 3,200 cases were investigated during the study period where 267 (8.3%) cases were of primary superficial malignant neoplasms, with 98 cases in the peak age group of 40-59 yr (36.7%) and a median age of 38.0 yr (range, 0.2-88 yr). The most frequent superficial cytodiagnosis was breast carcinoma, 79 (29.6%) cases; followed by non-Hodgkin's lymphomas, 37 (13.9%) cases; and soft tissue sarcomas, 26 (9.7%) cases. The overall male-to-female ratio showed preponderance to female patients (1:1.3). Carcinomas were identified more frequently in those >40 yr of age whereas sarcomas were identified in those <40 yr of age (P > 0.05). The most common malignant neoplasm in women was breast carcinomas found in 74 (27.7%) cases, whereas in men non-Hodgkin's lymphomas were found in 29 (10.9%) cases. Large proportions of carcinomas (88 cases, 33.0%), lymphomas (33 cases, 12.4%), and sarcomas (20 cases, 7.5%) were detected on the trunk, head, and neck, as well as on the lower limb regions, respectively. This study uncovered different types of superficial malignant neoplasms that are prevalent in the southwestern part of Ethiopia. The most common types of cytodiagnoses such as breast carcinomas, etc. may suggest that attention be given to future high-caliber prospective studies in trying to identify some of the associated strong risk factors for the disease under study. This study may be helpful to local health planners in prioritizing some of the commonest malignancies. Some of the diagnostic challenges of lymphomas and thyroid follicular lesions were shown also. This investigation is the first in Ethiopia and therefore may act as baseline data for similar studies in the future.

Using Gene Expression Profiling to Differentiate Benign versus Malignant Thyroid Tumors

DNA microarrays allow quick and complete evaluation of a cell's transcriptional activity. Expression genomics is very powerful in that it can generate expression data for a large number of genes simultaneously across multiple samples. In cancer research, an intriguing application of expression arrays includes assessing the molecular components of the neoplastic process and utilizing the data for cancer classification (Miller LD, et al. Cancer Cell 2002;2:353-61). Classification of human cancers into distinct groups based on their molecular profile rather than their histological appearance may prove to be more relevant to specific cancer diagnoses and cancer treatment regimes. Several attempts to formulate a consensus about classification and treatment of thyroid carcinoma based on standard histopathological analysis have resulted in published guidelines for diagnosis and initial disease management (Sherman SI. Lancet 2003;361:501-11). In the past few decades, no improvement has been made in the differential diagnosis of thyroid tumors by fine needle aspiration biopsy, specifically suspicious or indeterminate thyroid lesions, suggesting that a new approach to this should be explored. Therefore, in this study, we developed a gene expression approach to diagnose benign versus malignant thyroid lesions in 73 patients with thyroid tumors. We successfully built a 10 and 6 gene model able to differentiate benign versus malignant thyroid tumors. Our results support the premise that a molecular classification system for thyroid tumors is possible, and this in turn may provide a more accurate diagnostic tool for the clinician managing patients with suspicious thyroid lesions.

Computer-assisted cell morphometry and ploidy analysis in the assessment of thyroid follicular neoplasms

Conventional cytology cannot discriminate between benign and malignant follicular neoplasms. Our study evaluated the diagnostic role of computer-assisted image analysis in the presurgical assessment of thyroid follicular neoplasms. Fifty-eight patients (14 males, 44 females, age range, 45-75 years) who underwent surgery for cytologic diagnosis of thyroid follicular neoplasm were studied. All patients were first evaluated on clinical grounds and assigned a high/low suspicion of malignancy on the basis of gender, age, and nodule size. Cell image analysis was subsequently performed using a Cytometrica BYK Gulden microscope image processor on Feulgen-stained thyroid cytologic smears. A different population of 50 benign and 50 malignant, histologically evaluated nodules was studied in order to establish image analysis criteria suggestive of thyroid malignancy. Ploidy histogram, proliferation index (PI), nuclear area coefficient of variation (NACV), and anisocariosis ratio (AR) were studied. Thyroid cancer was diagnosed in 16 of 58 follicular neoplasms. Only 7 of these lesions were clinically suspicious (43.7%), whereas 14 of 16 (87.5%) malignant tumors were identified by image analysis. Positive and negative predictive values of image analysis versus clinical evaluation were 46.6% versus 30.4% and 92.8% versus 74.3%, respectively. The distribution of ploidy pattern was different in benign versus malignant follicular neoplasms (chi2 8.25, p = 0.016), malignant lesions showing an increased frequency of heteroclonal aneuploid DNA content (37.5% vs. 7.1%). Increased PI (mean +/- standard deviation (SD) = 11.3 +/- 5.7 vs. 7.1 +/- 6.1; p < 0.01) and NACV (mean +/- SD = 25.28 +/- 1.89 vs. 20.14 0.91; p < 0.01) levels were also observed in malignant follicular neoplasms. In conclusion, computer-assisted image analysis may profitably support clinical evaluation in the assessment of thyroid follicular neoplasms.

Thyroid carcinoma diagnosis based on a set of karyometric parameters of follicular cells

BACKGROUND

In the works of various authors, performed with the help of morphometry, an assessment of cell changes was carried out, as a rule, by one sign of their atypia (e.g. area of cell nuclei). Moreover, the selective analysis of morphometric data for certain nosologic forms was performed. Such an approach allowed researchers to develop only additional diagnostic criteria of thyroid carcinoma. At the same time, the use of a set of quantitative signs of cell atypia as a criterion for tumor malignancy made it possible to improve oncologic diagnosis. In this study, which is a first step in the development of a quantitative approach to thyroid carcinoma diagnosis, a system of karyometric parameters was developed with the help of morphometry of cytologic material of patients with major nosologic forms of thyroid pathology (papillary and follicular carcinoma, follicular adenoma, autoimmune thyroiditis, and nodular colloid and diffuse toxic goiter). The significance of each parameter in thyroid carcinoma diagnosis was evaluated.

METHODS

Thyroid cells of autopsy, operative, and aspiration biopsy material were the object of the study. One hundred fifty-two preparations with histologically verified diagnosis were studied. Light morphometry was performed with the help of a semiautomatic computer analyzer of images. One hundred fifty thyroid nuclei were assessed in each preparation.

RESULTS

Among many karyometric parameters, six were selected: mean area of thyrocyte nuclei, ratio of frequencies, and number of classes on histograms of distribution of their area, coefficient and a free term of the regression equation to a scattered diagram of perimeter and nuclear area, and the discriminant index. Boundary values of these parameters between the malignant and benign pathology were united into an expert system for thyroid carcinoma diagnosis. Clinical trials of the system were performed. On the basis of the obtained results, the informativity (accuracy, sensitivity, specificity) of its karyometric parameters was assessed. The formula for calculation of the weighting coefficient for each parameter was derived, the diagnostic index being determined by the sum of their values.

CONCLUSIONS

An expert system was created based on a set of karyometric parameters reflecting the regularities of pathologic changes in thyrocyte nuclei with malignant and benign pathology. The informativity and weighting coefficients included into the system of parameters have been assessed, which made it possible to perform the probabilistic diagnosis of thyroid carcinoma.

Leu-7 immunoreactivity in cytologic specimens of thyroid lesions, with emphasis on follicular neoplasms

Anti-Leu-7 (HNK-1, CD 57) antibody, a marker for natural killer lymphocytes, was employed by Ghali et al. (Hum Pathol 1992;23: 21-25) to study surgically resected formalin-fixed, paraffin-embedded thyroid lesions. They demonstrated strong immunoreactivity of this antibody with thyroid carcinomas, both follicular and papillary, and only occasional weak immunoreactivity with colloid goiters and follicular adenomas. We studied cytologic specimens (primarily fine-needle aspiration biopsy specimens) from 44 thyroid lesions, including 10 follicular carcinomas, 14 follicular adenomas, seven adenomatous nodules, six papillary carcinomas, and seven cases of Hashimoto's thyroiditis. All follicular carcinomas exhibited immunoreactivity to anti-Leu-7 antibody, usually of a moderate to strong degree (9/10); however, six of 14 follicular adenomas yielded similar results. The patterns of immunoreactivity in the other lesions were similar to those previously described (Ghali et al., Hum Pathol 1992;23:21-25). It does not appear that anti-Leu-7 antibody can be used as a specific marker of malignancy in the cytologic assessment of follicular neoplasms of the thyroid.

"Cellular adenomatoid nodules" of the thyroid: review of 219 fine-needle aspirates

We reviewed 219 consecutive thyroid aspirates previously diagnosed as "cellular adenomatoid nodule," applying the criteria presented in this paper and reclassifying them as 146 adenomatoid nodules (AN), 31 cellular adenomatoid nodules (CELL-AN), 29 cellular adenomatoid nodules vs. follicular neoplasms (CELL-AN vs. FN), 5 follicular neoplasms (FN), 2 FN of oxyphilic cell type, 4 papillary carcinomas, and 2 chronic lymphocytic (Hashimoto's) thyroiditis. Of the 146 adenomatoid nodules, 14 occurred in multinodular goiters on histologic examination. Of the 31 CELL-AN, five had surgery: two were follicular adenomas, one was papillary carcinoma, and two were multinodular goiters. Of the 29 CELL-AN vs. FN, 11 had surgery: six were follicular adenomas, two were follicular carcinomas, two were multinodular goiters, and one was Hashimoto's thyroiditis. Surgery on four FN showed follicular adenomas (a fifth patient was lost to follow-up). Of the two FN of oxyphilic cell type, one was a multinodular goiter and the other a follicular adenoma with oxyphilic cells. Three of the four papillary carcinomas were confirmed histologically (one patient was lost to follow-up). Of the two cases showing Hashimoto's thyroiditis, one was diagnosed as FN on repeat aspiration and follicular carcinoma at surgery. After review, we identified 40 patients at higher risk of harboring a neoplasm and 31 with cellular adenomatoid nodules. Twenty-five underwent surgery with the above results. In the classification of follicular lesions of the thyroid by FNA, adherence to strict cytologic criteria helps identify those patients who will benefit most from surgery.

Predictive value of fine-needle aspiration of the thyroid in the classification of follicular lesions

BACKGROUND

Fine-needle aspiration has been less valuable in the diagnosis of follicular lesions than for other neoplasms of the thyroid. It has been observed that follicular carcinoma is found in microfollicular, but not macrofollicular lesions, and this has served as a guide to management for many surgeons. The authors attempted to determine what cytologic parameters might usefully distinguish these types of follicular lesion.

METHODS

The histologic findings and cytology of 56 thyroid lobectomies for follicular lesions that had adequate preoperative fine-needle aspiration of the thyroid (FNAT) were reviewed. Histologic specimens were classified into macrofollicular, mixed, and microfollicular groups. Cytologic features examined included the presence of colloid, irregularity of cell arrangements within groups, the presence and size of flat and folded cell sheets, three-dimensional clusters, and microfollicles and macrofollicles.

RESULTS

Of the histologic specimens, 15 were preponderantly (> 70%) microfollicular, 19 were mixed, and 22 were predominantly (> 70%) macrofollicular. Three cytologic features were useful in their distinction: none of the predominantly microfollicular but 24% of the mixed and predominantly macrofollicular had abundant colloid (P = 0.048). Likewise, none of the predominantly microfollicular but 27% of the mixed and predominantly macrofollicular had large follicles (P = 0.026). Finally, 73% of the predominantly microfollicular but only 37% of the mixed and predominantly macrofollicular showed irregularity or crowding of cells in groups (P = 0.018).

CONCLUSIONS

Used in combination, abundant colloid, regular spacing, and large follicles are helpful in distinguishing macrofollicular and mixed lesions from microfollicular ones, which have a higher malignant potential.

Well differentiated follicular neoplasms of the thyroid: reproducibility and validity of a 'decision tree' classification based on nucleolar and karyometric features

This study was conducted on fine-needle aspirates of well differentiated follicular neoplasms of the thyroid. A 'decision tree' classification based on the percentage of nucleolated nuclei, percentage of nuclei with two or more nucleoli and mean major nuclear diameter was adopted. We observed that the reproducibility and the validity of the follicular adenoma vs follicular carcinoma discrimination are greater than in the subjective evaluation. Moreover, similar classification results were obtained when measurements were performed either with a fully automated image analysis system or with semiautomatic or manual instrumentation. As for reproducibility of the inter-instrument comparisons, the k statistic values ranged from 0.85 to 1.00 (mean value 0.90, that is, an 'almost perfect' degree of agreement); in the subjective evaluations, the inter-observer comparisons showed values ranging from 0.20 to 0.56 (mean value 0.37, that is, 'fair'). In the decision tree classification, feature value thresholds were selected in order to have specificity of 100% and the predictive value of a positive result (carcinoma) of 100%; accuracy was 87% (range 86-89%), sensitivity 74% (71-79%), the predictive value of a negative result (adenoma) 79% (78-82%). In the subjective evaluation the values were as follows: accuracy 67% (64-71%), sensitivity 57% (50-64%), specificity 77% (71-79%), predictive value of a negative result (adenoma) 64% (61-69%), predictive value of a positive result (carcinoma) 71% (67-75%). The conclusion is that, by using a routine microscope equipped with a micrometer, the preoperative diagnosis of follicular carcinoma from smears can be formulated with a high degree of certainty.

Nodular goiter: a histo-cytological study with some emphasis on pitfalls of fine-needle aspiration cytology

A comprehensive comparative histo-cytological study of 48 nodular goiters from an endemic goiter region was undertaken. Practically all features observed on the biopsies were identified, although with less frequency, on the smears. In agreement with previous observations, characteristic components of nodular goiter (NG) in aspirates included small to medium size epithelial cells with regular round nuclei, honeycomb pattern, large follicles, papillae showing the previously mentioned epithelial features, oxyphilic cells, and moderate to abundant background colloid material and thyroid phagocytes (macrophages). All eight features occurred together in only 2% of the studied cases, seven in 6 (12.5%), six in 4 (8%), five in 6 (12.5%), four in 12 (25%), three in 6 (12.5%), two in 11 (23%), and one in 2 (4%) cases, respectively. Regardless of the number and combination of features present, specific identification of NG on the smears may not always be possible and diagnostic pitfalls include thyroid cyst, Hashimoto's thyroiditis, granulomatous lesions, and, more frequently, follicular neoplasia. Our findings suggest that thyroid aspirates should be analysed with critical clinico-pathological approach and surgery considered only for nodules that are clinically suspicious or unresponsive to hormonotherapy when a diagnosis of follicular neoplasia is made.

Cytologic diagnosis of non-oxyphil follicular neoplasias of the thyroid. Multivariate classification procedure based on quantitative nucleolar features

The study was done on cytologic material of 58 non-oxyphil follicular neoplasias of the thyroid, 32 of which were adenomas and 26 carcinomas. Three groups of nucleolar features were quantified using a routine microscope with an ocular micrometer: frequency-, size-, and margination-related features. Since value overlap was present between two categories for all the variables, stepwise discriminant analysis was applied. The following three features were selected by the computer for calculation of one canonical discriminant function: percentage of marginated nucleoli, percentage of nuclei with one nucleolus, mean major nucleolar diameter. The percentage of agreement between morphologic and computer classifications was 95%. Two follicular adenomas were allocated to the carcinoma category, whereas one follicular carcinoma was allocated to the adenoma category. Out of 58, 52 were diagnosed by the computer into one of the two diagnostic categories with a very high probability, i.e. P greater than 0.75, the remaining 6 being considered intermediate.

Contribution of fine needle aspiration cytology to diagnosis and management of thyroid disease

AIMS

To determine the role of fine needle aspiration cytology (FNAC) in the diagnosis and management of thyroid disease.

METHODS

Clinical histories of 144 patients who had undergone FNAC of the thyroid were analysed. Clinical presentation, non-invasive investigations including hormone assays, ultrasound, and isotope scan procedures were compared with FNAC diagnoses in all cases and with histological diagnosis in the 28 cases (19%) that had undergone surgery. Clinical management was decided upon combining all of the above investigations. The relative contribution of the FNAC was divided into: essential, additional and non-contributory, misleading.

RESULTS

FNAC diagnoses included: 29 (16%) benign colloid goitre, 56 (39%) benign cystic goitre, 24 (17%) thyroiditis, and 22 (15%) neoplasms. Nineteen (13%) of the specimens were unsatisfactory. When compared with clinical diagnoses based on non-invasive diagnostic investigations FNAC represented no improvement on the diagnosis of benign colloid/cystic goitre (55% v 54% respectively). It represented an improvement on the diagnosis of thyroiditis (9% v 17% respectively). FNAC decreased clinically suspicious lesions in which 22 neoplasms were diagnosed from 37% to 15%. Eleven patients with neoplasms underwent surgery and neoplasms were confirmed histologically. Others including lymphoma, metastatic carcinoma, and analplastic carcinoma were managed conservatively. There were four false negative FNAC diagnoses (3%) in clinically suspicious lesions, found on histology to be benign follicular adenomas.

CONCLUSIONS

FNAC had an essential role in the diagnosis and management of 23% of our patients, a confirmatory role in 61% of patients, a non-contributory role in 13% when specimens were inadequate, and was misleading in 3% where results were false negative. The positive identification of thyroiditis and neoplasia stands on its own as a justification for FNAC.

A logistic model for thyroid lesions

A stepwise logistic regression analysis was performed in 27 cases of papillary carcinoma thyroid (PC), 20 follicular neoplasms (FN), 30 cases of Grave's disease (GD), and 40 cases of colloid adenomatous goitre (CAG). The three most important variables in predicting PC were papillary clusters, dense cytoplasm, and intranuclear cytoplasmic inclusions, whereas the predictors of FN were high cellularity combined with a prominent acinar pattern. A few cases of GD and CAG showed a cytologic overlap with PC and FN, respectively. Regression analysis established high cellularity, fire flare appearance, and epitheloid granulomas as reliable predictors of GD, whereas abundant colloid with or without foam cells and follicles associated with colloid (FAC) were important variables in CAG.

Parenchymatous thyroid nodules: a histocytological study of 31 cases from a goitrous area

AIMS

To analyse the benefits and limitations of fine needle aspiration in the cytological differentiation of parenchymatous nodular goitres from follicular tumours in an endemic area.

METHODS

Cytological smears of fine needle aspirates from 31 parenchymatous nodular goitres were studied. A sample from the punctured nodules was fixed in formalin and stained with haematoxylin and eosin for histological analysis.

RESULTS

All nodules occurred in a multinodular gland, were well circumscribed, did not compress surrounding thyroid tissue, and for the most part, were unencapsulated. Two cases showed cytological features of nodular goitre, two of colloid cysts; the remaining 27 were cytologically indistinguishable from follicular lesions.

CONCLUSIONS

Most of the parenchymatous nodules studied had features suggestive of follicular lesions or neoplasia, but surgical treatment should only be considered after hormone treatment has proved unsuccessful, and when they are not suspected as malignant clinically. Fine needle aspiration is useful as a diagnostic and screening aid, but the results should be interpreted with caution to prevent unnecessary surgery.

Quantitative analysis of nucleolar margination in diagnostic cytopathology

The diagnostic value of nucleolar margination, defined as the percentage of nucleoli touching the nuclear membrane, was investigated in 359 cytological preparations of benign and malignant lesions of the thyroid, breast, prostate and central nervous system. Premalignant lesions of the uterine cervix and non-invasive papillary carcinomas of the bladder were also examined. It was observed that the percentages in benign lesions were, in general, lower than in the malignant and that the values increased progressively with increasing grade in the cervix and bladder. When the overlap index was calculated, this gave exact information on the usefulness of nucleolar margination in distinguishing benign from malignant lesions, particularly in the prostate and thyroid and, to a lesser extent, in the breast and central nervous system. As for lesions of different grades, the calculation of the index allowed the identification of two subgroups, one corresponding to low grades (mild cervical dysplasia or urothelial papillary carcinoma of grade 1), the other subgroup to high grades (severe cervical dysplasia and carcinoma in situ, or papillary carcinoma of grade 3). Moderate dysplasia cases and grade 2 papillary carcinomas do not appear as separate intermediate categories but rather show values falling into the range of either the higher or lower grades. The margination values obtained from the cytological preparations corresponded well to those in the histological slides obtained from the resected specimens. In conclusion, nucleolar margination appears to be a feature which is easy to evaluate in a reproducible way and useful in cytological diagnosis.

Thyroid tumors: cytomorphology of follicular neoplasms

From 2,012 fine-needle aspirations (FNA), performed by us between the years 1984 and 1988, we present a detailed cytomorphologic analysis of 95 cases that were diagnosed as neoplastic on histology and/or cytology and those that received an equivocal cytodiagnosis. Discussed are 37 lesions that have been diagnosed on cytology and/or histopathology as follicular neoplasms. In this group, there were 22 cases of histologically proven follicular carcinoma and 11 follicular adenomas. Three cases of multinodular goiter and one case of Hashimoto's thyroiditis with marked follicular hyperplasia have also been included because they received either a neoplastic or an equivocal cytodiagnosis. Of 22 follicular carcinomas, 12 were diagnosed on FNA as follicular neoplasms, eight as follicular carcinoma, one was a false-negative benign cytodiagnosis, and one was equivocal. Of 11 follicular adenomas, seven were diagnosed as follicular neoplasms and four were cytologically equivocal. Three cases of multinodular goiter and one Hashimoto's thyroiditis had been diagnosed on FNA as either follicular neoplasm or equivocal.

Value of quantitative nucleolar features in the preoperative cytological diagnosis of follicular neoplasias of the thyroid

Nucleolar prevalence, size, and outline were investigated on cytological material from cold thyroid nodules obtained by fine needle aspiration. The percentage of nucleolated nuclei in follicular adenoma (32 cases) was less than in follicular carcinoma (26 cases). In adenoma most nuclei contained one nucleolus, and nuclei with two or more nucleoli were less common than in carcinoma where most cases showed the highest nucleolar diameter values. There was some overlap between adenomas and carcinomas, however, when the mean of the 10 largest values of the major nucleolar diameter was considered. In follicular carcinoma the percentage of marginated nucleoli--that is, those touching the nuclear membrane--was, in general, greater than 20%; in adenoma the values were equal to or lower than 16%. The overlap index showed that the percentages of marginated nucleoli and nucleolated nuclei are the two best discriminatory features between adenoma and carcinoma.

Cytopathology of follicular tumours of the thyroid with clear cell change

A retrospective cytological study of nine follicular tumours of the thyroid with clear cell change was undertaken. In five clear cell adenomas and one moderately differentiated clear cell follicular carcinoma the epithelial cells occurred singly or in sheets and clusters; they sometimes assumed a trabecular or follicular pattern. The cells usually had pale diffusely vacuolated cytoplasm with ill-defined boundaries, a variable degree of anisonucleosis, nucleolar enlargement, and nuclear overlapping. Smears from a signet-ring cell adenoma contained in addition a few cells with large cytoplasmic vacuoles and compressed eccentric nuclei. In these cases a cytological diagnosis of 'follicular lesion' (or follicular neoplasia), clear cell type or signet-ring cell type, was given. A cytodiagnosis of 'carcinoma' was made only in the poorly differentiated follicular carcinoma-clear cell variant studied which showed unequivocal features of malignancy. Features suggestive of thyroid cyst, nodular goitre, Hashimoto's thyroiditis, and cell hyperactivity (marginal vacuoles, 'fire flare') were also found in the aspirated specimens of these cases of clear cell tumour of the thyroid.