Fine needle aspiration biopsy cytology in the diagnosis of thyroid cancer: comparative study of 213 operated patients

Correlation of fine needle aspiration cytology with histopathology in patients undergoing thyroid surgery

<b>Introduction:</b> Thyroid swellings are one of the most common swellings in the neck. They pose a major problem in developing countries like India, considering the high endemicity for iodine deficiency disorders. Thyroid gland is affected in many conditions. Out of these, majority are benign while less than 5% are malignant. Multiple noninvasive and invasive diagnostic tests are available for the diagnosis of thyroid swelling. However, at present, FNAC is considered the gold standard investigation. Despite the high sensitivity and specificity, FNAC has its limitations. Histopathological examination of surgically excised thyroid swelling is the confirmatory gold standard to determine the pathology of the thyroid gland. <br><b>Material and method:</b> This prospective and observational study was conducted in the Department of Otorhinolaryngology (ENT) in collaboration with the Department of Pathology in a tertiary care hospital and medical school. A total of seventy patients were included. <br><b>Results:</b> The diagnosis on FNAC was correlated with histopathology. Statistical analysis showed FNAC had a sensitivity of 83.3%, specificity of 100%, positive predictive value of 100%, negative predictive value of 96.7%. However, the overall accuracy in this study was determined to be 95.71%. Results were found to be statistically significant (P < 0.05). <br><b>Conclusions:</b> The diagnostic role of FNAC in thyroid lesions is of utmost importance in making preoperative diagnosis. FNAC was found to be highly sensitive and specific for diagnosing thyroid lesions but the final HPE is considered as a gold standard.

Management of nondiagnostic thyroid fine-needle aspiration biopsy: survey of endocrinologists

OBJECTIVE

To evaluate the approach of endocrinologists in the setting of nondiagnostic thyroid fine-needle aspiration (FNA) biopsies.

METHODS

In 2002, we surveyed physicians attending the national annual meetings of the American Association of Clinical Endocrinologists and the Endocrine Society of North America, using a 13-item questionnaire. The responses were tallied and analyzed.

RESULTS

Of the 143 respondents, 139 were endocrinologists, with a male:female ratio of 2.5:1. Most respondents were involved in a medical practice in North America, but Europe, Asia, New Zealand, and Australia were also represented. Of those performing thyroid FNA biopsy, 31% used thyroid ultrasound guidance. Among the survey respondents, 16%, 49%, 20%, and 15% performed less than 2, 2 to 5, 6 to 10, and more than 10 thyroid FNA biopsies per month, respectively. Among the respondents, 13.5%, 44%, 28.5%, 10%, and 4% had non-diagnostic rates of less than 5%, 5 to 10%, 11 to 20%, 21 to 30%, and more than 30%, respectively. The approach of the respondents to an initially nondiagnostic FNA was repeated FNA biopsy in 87%, observation in 7%, levothyroxine suppression in 4%, and thyroid scintigraphy in 2%. Respondents believed that the most cost-effective approach in a patient with nondiagnostic FNA was repeated biopsy (82%), monitoring the size of the thyroid nodule (17%), and surgical referral (<1%). No one was willing to repeat the thyroid biopsy more than three times.

CONCLUSION

On the basis of findings in our survey, most endocrinologists repeat thyroid FNA at least once when confronted with a nondiagnostic result. No published studies have demonstrated the cost-effectiveness of this approach versus proceeding to surgical intervention or observation. We hope that this survey will encourage further studies on this issue.

Large remnant 131I ablation as an alternative to completion/total thyroidectomy in the treatment of well-differentiated thyroid cancer

BACKGROUND

An alternative to completion thyroidectomy for well-differentiated thyroid carcinoma is to ablate the remnant lobe with 131 I. The purpose of this study is to review our own experience with large remnant ablation.

METHODS

A retrospective review of 169 patients with well-differentiated thyroid cancer treated at one institution over a 14-year period was undertaken. Seventy-one patients who underwent partial thyroidectomy (PT) followed by 131 I ablation were identified. This group was compared to 98 patients treated with total thyroidectomy (TT).

RESULTS

Mean follow-up was 6.2 years for the 71 PT + 131 I versus 4.7 years for the 98 TT patients (P = .184). Recurrence occurred in 4 of 71 PT + I 131 patients (5.6%) versus 9 of 98 TT patients (9.2%) (P = .393). Other than a tendency for the size of the primary to be slightly larger and for the histology to be follicular carcinoma in the PT + 131 I patients, the 2 groups were nearly identical in age, gender, and other prognostic factors such as capsular invasion and metastases.

CONCLUSIONS

Large-dose ablation with 131 I is a viable alternative to completion thyroidectomy. Recurrence rates over an average 6-year period are similar to TT. Long-term monitoring of these cohorts is required.

Total versus subtotal thyroidectomy for the management of benign multinodular goiter in an endemic region

BACKGROUND

Because controversy still continuous to surround use of total thyroidectomy for the management of benign multinodular goiter, the present study aims to prospectively compare the safety and efficacy of total thyroidectomy with subtotal thyroidectomy.

METHODS

A total of 200 consecutive patients with benign multinodular goiter were assigned to have either total thyroidectomy (n = 105) or subtotal thyroidectomy (n = 95) based on preoperative evaluation, intraoperative macroscopic findings and nodular dissemination. The patients with no healthy tissue or nodules localized in the dorsal part of the gland, which are usually left during normal subtotal resection, were assigned to the total thyroidectomy group. Demographic details, biochemical findings, indications for operation, operating time, specimen weight, complications and hospital stay were noted.

RESULTS

There was no significant difference in the sex, hormonal status or duration of goiter between the two groups (P = 0.74, P = 0.59 and P = 0.59, respectively). The mean operating time was longer (148.52 min +/- 51.10 vs 135.10 min +/- 32.47, P = 0.03), and the mean weight of the specimens was greater (228.40 g +/- 229.91 vs 157.01 g +/- 151.23, P = 0.01) for total rather than subtotal thyroidectomy. Either temporary recurrent laryngeal nerve (RLN) palsy or hypoparathyroidism occurred in 10 (9.3%) or 12 (11.4%) of the patients undergoing total compared with six (6.3%) or nine (9.5%) of the patients undergoing subtotal thyroidectomy (P = 0.40 and P = 0.65, respectively). Either permanent RLN palsy or hypoparathyroidism was observed in one patient undergoing total thyroidectomy (P = 0.34 for each comparison). The mean hospital stay was longer in the total thyroidectomy group (2.24 days +/- 1.18 vs 1.89 days +/- 0.72 for subtotal thyroidectomy, P = 0.01).

CONCLUSIONS

The present study shows that total thyroidectomy can be performed without increasing risk of complication, and it is an acceptable alternative for benign multinodular goiter, especially in endemic regions, where patients present with a huge multinodular goiter.

Reporting thyroid fine-needle aspiration: Literature review and a proposal

Reporting schemes for thyroid fine-needle aspirations in the literature were reviewed and classified according to the number of categories in the scheme and the significance of each category. The sensitivity, specificity, and positive predictive and negative values were determined for each scheme, if possible. A reporting scheme based on the probability of finding carcinoma on histology is proposed.

Analysis of inconclusive fine-needle aspiration of thyroid follicular lesions

To evaluate all inconclusive fine-needle aspiration biopsy (FNAB) specimens from thyroid follicular lesions with subsequent histologic diagnosis at St John Hospital and Medical Center, Detroit, MI. The criterion for specimen adequacy used in our institution was also reexamined to determine whether it was too stringent. We reviewed 45 inconclusive FNAB samples. Only cases that underwent surgical intervention were considered. Specimen adequacy was determined by the presence of at least 8-10 tissue fragments of well-preserved follicular epithelium on at least two slides; each tissue fragment should have a minimum of 8-10 cells. Different cytologic characteristics-cellularity, cellular architecture, nuclear pleomorphism, inclusion/grooves, chromatin, Hürthle cell change, lymphocytes, macrophages, colloid, and multinucleated giant cells-were scored and compared with final surgical diagnosis. The surgical procedure performed was also analyzed. Review of these 45 surgical specimens found 28 (62.2%) multinodular goiters, 14 (31.1%) nodular hyperplasias, 2 (4.4%) follicular adenomas, and one (2.2%) with invasive follicular carcinoma. Forty-three (95.6%) of these cases were female and 2 (4.4%) were male. Cytologic review showed 2 acellular samples, 10 cases containing macrophages only, 10 aspirates with macrophages and an inadequate number of follicular cells, and 23 specimens with an inadequate number of follicular cells. Twenty-three patients underwent total thyroidectomy; 20, lobectomy; and 2, isthumusectomy. Almost 98% of the patients with inconclusive FNAB had benign lesions. This finding encouraged us to continue using our criteria for adequacy because of the importance of a negative report. Patients in our series, who underwent thyroidectomy after an inconclusive or nondiagnostic aspirate, had a malignancy rate of 2.2%, which was no worse than patients with a benign preoperative diagnosis. A balanced approach with careful follow-up for nondiagnostic cytology is prudent.

Cytologic diagnosis of medullary carcinoma of the thyroid gland

The cytomorphologic features in fine-needle aspiration (FNA) biopsies from 91 histologiacally verified medullary carcinomas of the thyroid (MCT) were investigated. FNA was able to diagnose neoplasms with indications of surgical removal in 98.9% of cases and moreover, was accurate in specific tumor typing in 89% of cases. The most important cytologic criteria of MCT with FNA are: dispersed cell-pattern of polygonal or triangular cells, azurophilic cytoplasmic granules, and extremely eccentrically placed nuclei with coarse granular chromatin and amyloid. These and other cytologic features of MCT are discussed in detail. Fourteen cases of thyroid tumors originally diagnosed as MCT by cytology are illustrated to discuss the differential diagnosis of MCT and its potential pitfalls. If MCT is cytologically presumed but amyloid and azurophilic cytoplasmic granules are not demonstrated, the use of immunostaining is necessary for a correct tumor typing. The application of immunocytochemistry in MCT is discussed.

Gender, clinical findings, and serum thyrotropin measurements in the prediction of thyroid neoplasia in 1005 patients presenting with thyroid enlargement and investigated by fine-needle aspiration cytology

One thousand five euthyroid patients (870 females and 135 males, mean age 47 years), who presented with thyroid enlargement were evaluated by fine-needle aspiration cytology (FNAC) of the thyroid as the first-line investigation. The final cytological or histological diagnosis was determined after surgery (n = 312) or clinical follow-up for a minimum period of 2 years (range 2-14 years, mean 6.7 years). Goiter type was assessed clinically and was classified as diffuse in 147, multinodular in 247, or solitary nodule in 611. The overall sensitivity and specificity of the procedure in the detection of thyroid neoplasia was 88% and 89%, respectively. Males who presented with thyroid enlargement had significantly higher rates of malignancy (p = 0.007) and neoplasia (benign + malignant) (p = 0.002) than females, as did subjects with solitary nodule compared with diffuse or multinodular goiters (malignancy p = 0.001, neoplasia p < 0.001). Subjects with normal thyrotropin (TSH) (>0.4 mU/L) at presentation had a nonsignificantly increased risk of thyroid neoplasia (p = 0.07) and malignancy, in contrast to those with low TSH (<0.4 mU/L). We confirmed FNAC of the thyroid to be an accurate test in the detection of thyroid neoplasia. Gender and goiter type at presentation both contribute significantly to the prediction of the diagnosis of thyroid neoplasia.

Imaging the thyroid

Thyroid imaging has historically relied heavily on scintigraphy, although, not surprisingly in view of the superficial position of the gland, ultrasound has assumed an increasingly prominent role in recent years. The other cross-sectional imaging modalities can also be useful, and the emergence of new radiopharmaceuticals and the increasingly central role of fine needle aspiration cytology have further added to the range of diagnostic techniques available. This review attempts to summarize the current state of knowledge, and makes some suggestions for the most efficient use of imaging resources in the investigation of thyroid disease.

Value of repeated fine-needle aspiration cytology and cytologic experience on the management of thyroid nodules

Although fine-needle aspiration is being currently accepted as the most reliable method to select patients with thyroid nodules for surgery, controversy remains about the accuracy in distinguishing benign nodules. We present our results from 636 fine-needle aspirations performed from 1984 to 1989. Our article focuses on the value of cytologic expertise and repeated punctures for follow-up of benign nodules. We found annual figures for specificity and positive predictive value to increase steadily from 1984 to 1989, thus suggesting that the power of the test is proportional to the experience of the cytologist. We also state that the value of performing repeated punctures for the follow-up of unselected benign nodules is low.

Completion thyroidectomy for differentiated thyroid carcinoma

Completion thyroidectomy is performed because of a deferred diagnosis of differentiated carcinoma of the thyroid or a significant thyroid remnant after initial operation. During a period of 6 years, data from 40 patients with differentiated thyroid carcinoma undergoing completion thyroidectomy were retrospectively reviewed. There were 4 men and 36 women (1:9), and the average age was 39.6+/-1.9 years (range, 20 to 62 years). The indications for the initial surgery were a solitary thyroid nodule in 36 (90%) patients, multinodular goiter in 3 (7.5%) patients, and Graves' disease in 1 (2.5%) patient. Three patients underwent completion thyroidectomy during the same hospital stay. In the remaining 37 patients, completion thyroidectomy was performed 4 to 252 days (44.1+/-7.8 days) after the initial operation. The length of hospital stay for the initial operation was not different from that for completion thyroidectomy (5.1+/-0.3 days vs. 5.2+/-0.3 days). The length of time needed to accomplish the initial operation was not different from that required for the completion thyroidectomy (122+/-7.5 minutes vs. 110.8+/-5.9 minutes). There was no 30-day perioperative mortality. The postoperative morbidity in completion thyroidectomy consisted of transient hypoparathyroidism in 3 (7.5%) patients, permanent hypoparathyroidism in 1 (2.5%) patient, transient recurrent laryngeal nerve palsy in 1 (2.5%) patient, and permanent recurrent laryngeal nerve palsy in 1 (2.5%) patient. On the other hand, one transient recurrent laryngeal nerve palsy and one transient hypoparathyroidism occurred at the initial operation. Completion thyroidectomy is a safe procedure to remove the thyroid remnant.

Cystic thyroid lesions in children

BACKGROUND/PURPOSE

Cystic lesions of the thyroid encompass a wide and heterogeneous group of disease states in children, ranging from benign purely cystic entities to malignant tumors. The purpose of this study was to study both the presentation and management of cystic thyroid lesions in the pediatric population.

METHODS

A retrospective review of all thyroid masses presenting between 1978 and 1996 and found to be purely or partially cystic on ultrasound examination was conducted, looking at presentation, family history, laboratory values, ultrasound scan and radionuclide imaging, and pathological and cytological evaluation.

RESULTS

Twenty-four patients (19 girls, 5 boys) aged 6 to 18 years received the diagnosis of cystic lesions of the thyroid. Of these, 23 presented with painless neck masses, 21 were clinically euthyroid, only one had a single abnormal thyroid function test, only two had mildly positive antithyroid antibody test results, and nearly 30% had a positive family history of thyroid disease. Ultrasonography showed pure cysts in five patients and mixed solid cystic lesions in 19 patients. On scintiscan, six lesions were hot, 13 were cold, three showed normal uptake, and two were mixed. Treatment included either observation, aspiration, cyst sclerosis, surgery, or combinations thereof. Pathological and cytological results included follicular adenoma (n = 9), cystic degeneration (n = 6), multinodular goiter (n = 4), carcinoma (n = 2), branchial cleft cyst (n = 1), and undetermined (n = 2).

CONCLUSIONS

Thyroid cysts are often thought to represent benign degenerative disease. Our study, which is the first in the literature to specifically address thyroid cysts in children, shows that ultrasound scan is useful in evaluating thyroid masses, whereas laboratory and radionuclide are of less value, and that single lesions of mixed echogeneity are likely to represent neoplasms, a significant percentage of which are malignant.

Diagnostic accuracy of conventional versus sonography-guided fine-needle aspiration biopsy of thyroid nodules

Fine-needle aspiration biopsy (FNAB) is an accurate, slightly invasive, and safe method for the preoperative diagnosis of thyroid nodules. Recently, ultrasound guidance has been suggested as a valuable aid to enhance FNAB diagnostic performance. In this study, we have compared diagnostic accuracy of conventional FNAB (C-FNAB) versus sonography-guided FNAB (SG-FNAB) on a large sample population of 9683 patients with thyroid nodules. Over a 15-year period, 4986 patients were investigated by C-FNAB and 4697 underwent SG-FNAB. A valid cytological diagnosis was obtained in 85.9% of C-FNAB and in 91.5% of SG-FNAB cases, allowing detection of thyroid cancer in 1.6% and 2.1% of patients, respectively. The indeterminate pattern of follicular neoplasia was observed in 238 C-FNAB (5%) and in 272 (5.4%) SG-FNAB nodules. Specimens were cytologically inadequate in 433 C-FNAB (8.7%), but only in 167 SG-FNAB cases (3.5%). A total of 535 C-FNAB and 540 SG-FNAB nodules underwent surgery. False-negative results occurred in 7 C-FNAB nodules (2.3%), but only in 3 SG-FNAB cases (1%). Sensitivity, specificity, and global diagnostic accuracy of C-FNAB compared with SG-FNAB were 91.8% versus 97.1%, 68.8% versus 70.9%, and 72.6% versus 75.9%, respectively. Our results, based on a large population of thyroid nodules, demonstrate that SG-FNAB allows a more precise and adequate sampling of thyroid nodular lesions and is associated with a lower rate of false-negatives, thus improving global diagnostic accuracy in the preoperative selection of thyroid cancer.

Fine-needle aspiration biopsy of thyroid nodules: impact on clinical practice

The aim of the present study was to analyze the changes in our clinical practice due to the use of FNAB in the management of nodular thyroid disease. Patients attended the thyroid unit for thyroid nodules. The study comprises three periods: First, from January 1980 to May 1984, 226 patient. Second, from June 1985 to December 1990, 166 patients. Third, from January 1991 to December 1993, 403 patients.

DESIGN

retrospective the 1st period and prospective the 2nd and 3rd periods. During the 1st and 2nd periods, decision for surgery was based on clinical parameters together with results of 99Tc radionucleotide scan and B mode ultrasound studies. In the 3rd period surgical decision was based principally on cytologic results. We comparatively studied the frequency of surgical operation and frequency of malignancy in surgical thyroid specimens between the study periods. Determination of sensitivity, specificity and accuracy of the diagnostic methods was done. We observed a decrease in the frequency of patients requiring surgery, 89.9%, 67.8% and 46.6% for the 1st, 2nd and 3rd study periods, X2 = 114.7, p < 0.0001; and an increase in the frequency of malignancy in the surgical specimens, 14.7%, 24.4% and 32.9% for 1st, 2nd and 3rd periods respectively, X2 = 4.5, p < 0.05. The sensitivity 92.5% and 93.5%, the specificity 50.6% and 61.1%, and the accuracy 60.9% and 71.8% of the FNAB for the second and third periods respectively. The rates of false negative cytological specimens were 1.8% and 2.1% for 2nd and 3rd respectively, p > 0.05. Since the introduction of FNAB in the evaluation of our patients around 70% of these had a definitive preoperative diagnosis of either benign or malignant disease. Simplification in management of patients with nodular thyroid disease is the most important impact for the use of FNAB. Furthermore, a decrease in the number of patients requiring surgical treatment and an increase of malignant nodules in the specimens obtained by surgery were also observed. We think that FNAB is the most direct and accurate method in the management of patients with thyroid nodules.

Surgical considerations and approach to thyroid cancer

Patients with thyroid cancer can be safely treated by an experienced endocrine surgeon. More extensive initial surgery such as total or near-total thyroidectomy seems to decrease tumor recurrence and prolong life. When such operations can be done with minimal complications, we believe it is the treatment of choice because even low-risk patients have a 4% or 5% risk of eventually dying of thyroid cancer. If this risk of death from thyroid cancer can be decreased to 1% or 2% and the rate of serious complications is 1% or 2%, the authors believe total thyroidectomy is indicated. Most patients can be discharged within 1 day of total thyroidectomy.

Large cystic/solid thyroid nodules: a potential false-negative fine-needle aspiration

BACKGROUND

False-negative fine-needle aspiration (FNA) biopsy results of thyroid nodules are of particular concern because they imply missed malignant lesions. The purpose of this study was to identify characteristics of thyroid nodules that may lead to false-negative cytologic interpretation after FNA.

METHODS

We reviewed 90 consecutive patients who underwent preoperative FNA of thyroid nodules followed by thyroid surgery during a period of 27 months, including their clinical data, type and size of thyroid nodule, FNA cytology results, and final pathology report of the surgical specimen.

RESULTS

Thyroid nodules that had the highest probability of malignancy were those that were large (3 cm or larger), cystic/solid, or large and cystic/solid. The overall false-negative rate for preoperative FNA was 11%. Large, cystic/solid, and thyroid nodules with both characteristics had false-negative rates of 17%, 25%, and 30%, respectively, compared with 0%, 9%, and 17% for small (less than 3 cm), solid, and solid nodules 3 cm or larger, respectively.

CONCLUSIONS

Because of the high prevalence of malignancy in thyroid nodules that are large (3 cm or larger), cystic/solid, or large and cystic/solid and the high false-negative rate of FNA in diagnosing these lesions, thyroid lobectomy for diagnosis should be strongly considered in these patients even when FNA cytologic finding is interpreted as benign.

Evaluation of fine needle aspiration (FNA) cytology in the diagnosis of thyroid nodules

FNA cytology of 112 patients with thyroid nodules seen in a 5-year period in a general hospital setting, and the histology obtained from the 53 operated patients, were retrospectively analysed. The inadequacy rate of FNA cytology was 11%, sensitivity was 84% (16/19), specificity was 52% (15/29), positive predictive value was 53% (16/30) and negative predictive value was 83% (15/18). Extrapolating these figures to the whole study group a negative predictive value of 95% is put forward as a more realistic figure. The results and the clinical pitfalls of the use of FNA cytology in diagnosing thyroid nodules are discussed. The authors conclude that FNA cytology is a reliable first diagnostic step in the diagnosis of thyroid nodules, even in a general hospital setting.

Limitations of thyroid scanning in solitary thyroid nodules

During an 8-year period, 104 patients (19 males, 85 females) underwent surgery for a solitary thyroid nodule. There were 19 (18.3%) malignant nodules and 85 (81.7%) benign nodules. Malignancy occurred in 3 (15.8%) males and 16 (18.8%) females. Pre-operative scanning was performed prior to referral in 59 patients (52 had ultrasound, 41 had isotope scanning; the majority had both). Of the scanned patients, 12 (20%) had a malignant nodule while 7 (15.5%) of the 45 patients who did not have scanning had a malignant nodule. In patients who had an ultrasound scan, malignancy was found in 5 (23.8%) of the 21 solid nodules and 7 (22.7%) of the 31 cystic (or solid/cystic) nodules. In patients who had thyroid isotope scanning, malignancy was found in 6 (17.5%) of the 34 cold (non-functioning) nodules and 3 (43%) of the 7 warm or hot (functioning) nodules. Ultrasound and isotope scanning may be misleading and neither help to differentiate benign from malignant thyroid nodules which require surgical excision.

Comparison between preoperative cytology and intraoperative frozen-section biopsy in the diagnosis of thyroid nodules

The value of intraoperative frozen-section biopsy of thyroid nodules (solitary or dominant in a multinodular goitre) was examined in patients who underwent fine-needle aspiration cytology (FNAC) for diagnosis before operation. A total of 170 consecutive patients were evaluated and classified according to whether the cytological diagnosis was benign, suspicious or malignant. In the benign group, diagnostic accuracy was 98 per cent for FNAC and 97 per cent for intraoperative biopsy. In those with suspicious cytology, diagnostic accuracy was 12 per cent for FNAC and 96 per cent for intraoperative biopsy. In those with malignant cytology there was 100 per cent accuracy for FNAC and 76 per cent for biopsy. Intraoperative biopsy by frozen section is useful in patients undergoing surgery for a thyroid nodule with a 'suspicious' cytology. It adds no information in patients with a diagnosis of malignancy following cytological assessment and is of limited use in those in whom a benign lesion is diagnosed.

The diagnostic value of fine-needle aspiration biopsy under ultrasonography in nonfunctional thyroid nodules: a prospective study comparing cytologic and histologic findings

Fine-needle aspiration biopsy (FNAB) of thyroid nodules has been proposed as a preoperative screening method to reduce the number of patients with benign nodules referred for surgery. Only a few previously published studies have compared cytologic results with a systematic surgical control; furthermore, the role of ultrasound guidance for FNAB in obtaining representative material has been poorly evaluated. The authors tried to assess the diagnostic value of FNAB performed under ultrasonography in a series of patients with a cold nodule and a systematic surgical control. This prospective study included 132 consecutive patients, 19 men and 113 women, aged from 18 to 82 years. The rate of carcinomas was 13.8%. A very high rate of adequate material was obtained (96.2%). Sensitivity, specificity, and global accuracy were 95%, 87.7%, and 89%, respectively. These results, which are equivalent to those previously published but associated with a low level of insufficient material, emphasize the diagnostic value of thyroid FNAB.

The role of fine needle aspiration in the diagnosis of thyroid nodules: analysis of 795 consecutive cases

The utility of fine needle aspiration (FNA) and physical examination for selecting patients with palpable thyroid nodules for surgery was evaluated in 795 consecutive cases. Surgery was performed in 216 patients based upon the cytological diagnosis and clinical criteria. Excluding 42 patients who were lost to follow-up, the remaining 537 were regularly followed up (range, 2-10 years). Cytological findings were classified as malignant, histologic control recommended (suspicious), follicular tumor, benign, and unsatisfactory. Thirty-six aspiration biopsies were positive for malignancy and the diagnosis was confirmed histologically in 34 of them. In 65 patients with final histological diagnosis of malignancy, cytology was positive in 34, suspicious in 20, benign in 3 cases, and unsatisfactory in 8. All patients with cytological diagnosis of follicular tumor had a benign lesion at histology. There were two false positive and three false negative cytological results among the 216 histologically confirmed cases. Excluding unsatisfactory specimen sensitivity, specificity and the predictive value for a positive and a negative result were respectively 95%, 97.5%, 94.5%, and 97%. We conclude that FNA is a very reliable diagnostic test in the evaluation of thyroid nodules and is the best guidance in addition to clinical criteria for selecting patients to be submitted to surgery.

Solitary thyroid nodule: a prospective evaluation of nuclear scanning and ultrasonography

The aim of this study was to assess prospectively the value of thyroid nuclear scans and ultrasound examination in the preoperative investigation of patients with a solitary thyroid nodule. Total thyroid lobectomy for a solitary thyroid nodule was performed in 68 cases. Each patient had a thyroid isotope scan (except two women who were pregnant) and thyroid ultrasound examination. There were 10 (15 per cent) malignant nodules, 11 (16 per cent) benign neoplastic nodules and 47 (69 per cent) benign non-neoplastic nodules. All of the patients with malignant nodules who were scanned had a solitary cold nodule on thyroid scan, as did 40 (69 per cent) of those with benign solitary nodules. Ultrasound examination of the thyroid suggested correctly that one of 16 (6 per cent) cystic lesions, four of 16 (25 per cent) complex solid-cystic lesions and three of 18 (17 per cent) of solid lesions were malignant. One lesion reported as multinodular on ultrasonography and one reported as normal also turned out to be malignant. Thyroid isotope scans and ultrasound do not accurately differentiate between benign and malignant conditions and their routine use in the investigation of a solitary thyroid nodule should be abandoned.

Marginal vacuoles in metastatic thyroid carcinoma: a case report

A case of metastatic follicular carcinoma to the iliac bone in a 78-yr-old woman is presented. Fine-needle aspiration biopsy (FNAB) smears showed numerous, cohesive tumor cell groups with moderately abundant cytoplasm and distinctive, peripherally situated pink-staining vacuoles on May-Grünwald-Giemsa stain. The presence of marginal vacuoles strongly suggested the possibility of metastatic thyroid carcinoma. Immunohistochemical studies performed on a concomitant needle core biopsy showed immunoreactivity for thyroglobulin, supporting a thyroid derivation for this metastasis. To our knowledge, this is the first reported case in which marginal vacuoles ("flame cells") have been identified in a malignant thyroid condition.

Solitary thyroid nodule: diagnosis and management

Thyroid nodules are common. Most are benign lesions since clinically important thyroid carcinoma is a relatively rare disease. The most sensitive and specific test for the diagnosis of thyroid cancer is fine-needle aspiration biopsy, but its diagnostic accuracy depends upon whether or not one excises all suspicious nodules, thus including them as correctly diagnosed. Nevertheless, fine-needle aspiration biopsy is the most sensitive, specific, and cost-effective test for thyroid cancer. Therapy depends upon the cause of the thyroid nodule.

Multivariate analysis in solitary cold thyroid nodules for the diagnosis of malignancy

A stepwise logistic regression (SLR) was performed on 162 patients with a solitary and cold thyroid nodule in order to discriminate between malignant and benign lesions. Sixteen variables were recorded for each patient. The predictions of the logistic regression model were compared to the histological diagnoses in order to evaluate the accuracy of the classification. The value of the logistic function (LF) was calculated for each patient. Using the ROC curve approach, an optimum threshold value (OTV) corresponding to a 100% sensitivity was defined. The classification obtained with the OTV was validated using a cross-validation procedure (CVP). The significant variables selected by the SLR are (from the most significant to the least significant): cytologic result, sex, irregular margin on the Tc scintigraphy and homogeneity on the ultrasound examination. The OTV corresponds to a specificity of 73% for a sensitivity of 100%. The specificity and the sensitivity obtained with the CVP are 73% and 96% respectively. In conclusion, the classification of the patients according to the value of the LF is a highly accurate diagnostic procedure.

Fine-needle aspiration biopsy and the diagnosis of thyroid cancer

Conventional criteria for the evaluation of thyroid nodules are inaccurate in identifying the small proportion of malignant neoplasms. The diagnostic accuracy of fine-needle aspiration biopsy (FNAB) for cytology was therefore assessed in 562 patients with nodular thyroid disease, 373 of whom (66.4 per cent) had histological confirmation of the cytological diagnosis. Sixty-one aspiration biopsies were positive for malignancy, and the diagnosis was confirmed histologically in 59 of these (96.7 per cent). Thus, there were two false positive cytology results among 310 patients with proven benign disease (0.6 per cent). Four of sixty-three patients with proven carcinoma had a benign cytological diagnosis, a false negative rate of 6.3 per cent. In 57 of the 59 malignancies (96.6 per cent) correctly diagnosed by FNAB the histological type of tumour was successfully identified. Overall 367 of 373 patients received correct cytological discrimination between benign and malignant nodules, an overall accuracy of 98.4 per cent for FNAB. The sensitivity of the test was 93.7 per cent and the specificity 99.4 per cent. Besides being safe, cost-effective and reliable, FNAB directs the appropriate selection of patients for surgery and enables the correct operation to be performed for each type of tumour.