Management of thyroid nodules. I: History and physical examination, blood tests, X-ray tests, and ultrasonography

Malignancy risk of hyperfunctioning thyroid nodules compared with non-toxic nodules: systematic review and a meta-analysis

Background

Hyperfunctioning or hot nodules are thought to be rarely malignant. As such, current guidelines recommend that hot nodules be excluded from further malignancy risk stratification. The objective of this systematic review and meta-analysis is to compare the malignancy risk in hot nodules and non-toxic nodules in observational studies.

Methods

Ovid MEDLINE Daily and Ovid MEDLINE, EMBASE, Scopus, and Web of Science databases were searched. Observational studies which met all of the following were included: (1) use thyroid scintigraphy for nodule assessment, (2) inclusion of both hyperfunctioning and non-functioning nodules based on scintigraphy, (3) available postoperative histopathologic nodule results, (4) published up to November 12, 2020 in either English or French. The following data was extracted: malignancy outcomes include malignancy rate, mapping of the carcinoma within the hot nodule, inclusion of microcarcinomas, and presence of gene mutations.

Results

Among the seven included studies, overall incidence of malignancy in all hot thyroid nodules ranged from 5 to 100% in comparison with non-toxic nodules, 3.8–46%. Odds of malignancy were also compared between hot and non-toxic thyroid nodules, separated into solitary nodules, multiple nodules and combination of the two. Pooled odds ratio (OR) of solitary thyroid nodules revealed a single hot nodule OR of 0.38 (95% confidence interval (CI) 0.25, 0.59), toxic multinodular goiter OR of 0.51 (95% CI 0.34, 0.75), and a combined hot nodule OR of 0.45 (95% CI 0.31, 0.65). The odds of malignancy are reduced by 55% in hot nodules; however, the incidence was not zero.

Conclusions

Odds of malignancy of hot nodules is reduced compared with non-toxic nodules; however, the incidence of malignancy reported in hot nodules was higher than expected. These findings highlight the need for further studies into the malignancy risk of hot nodules.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13044-021-00094-1.

Follicular Carcinoma Masquerading as a Hot Nodule in a Pediatric Patient

Autonomous functioning thyroid nodules (AFTNs) are generally considered to be benign entities, with malignancy found in about 1 per cent considered to be rare in the general population. Because of this low rate, fine needle aspiration is generally not recommended, and these lesions are most often treated with radioactive iodine, medication, or surgery. However, AFTNs are exceedingly rare in the pediatric population and the optimal treatment is not defined. We present a 14-year-old female patient with an AFTN treated with surgical resection and found to contain a follicular carcinoma with capsular invasion.

The analysis of correlation between frailty index and postoperative complications of aged patients with nodular goiter

OBJECTIVE

To explore the correlation between frailty index (FI) and postoperative complications of aged patients with nodular goiter (NG).

METHODS

A total of 120 aged patients with NG undergoing operative treatment from May 2013 to October 2015 in our hospital were selected. All of them were divided into 3 groups according to the FI as follows: nonfrail group (FI < 0.2), intermediately frail group (0.2 ≤ FI < 0.4), and frail group (FI ≥ 0.4). Clinical data of patients about general data, body mass index, American Society of Anesthesiology (ASA) classification, hospital stays, and postoperative complications were examined. Then, the correlations between the indexes above and FI were examined.

RESULTS

Frailty index and the ASA classification have some relevance (r = .265, P = .007). The postoperative complication rates of total nonfrail group, intermediately frail group, and frail group were, respectively, 4 cases (11.4%), 11 cases (31.4%), and 24 cases (48.0%). With the increase in FI, the incidence of postoperative complications and hospital stays had also significantly increased. The area under receiver operating characteristic curve examining frailty's ability to forecast postoperative complications was 0. 815 (95% CI: 0.675-0.954, P = .000).

CONCLUSION

The level of frailty index is a risk factor for postoperative complications of aged patients with NG. The preoperative frailty index evaluation can provide reference evidence for the treatment of aged NG patients undergoing surgery.

Subclassification of the "grey zone" of thyroid cytology; a retrospective descriptive study with clinical, cytological, and histological correlation

Undetermined thyroid cytology precludes any definitive distinction between malignant and benign lesions. Recently several classifications have been proposed to split this category into two or more cytological subcategories related to different malignancy risk rates. The current study was performed retrospectively to investigate the results obtained separating “undetermined” cytologic reports into two categories: “follicular lesion” (FL) and “atypia of undetermined significance” (AUS). Biochemical, clinical, and echographic features of each category were also retrospectively analyzed. Altogether, 316 undetermined fine-needle aspirated cytologies (FNACs) were reclassified as 74 FL and 242 AUS. Histological control leads to a diagnosis of carcinomas, adenomas, and nonneoplastic lesions, respectively, in 42.2%, 20%, and 37.8% of AUS and in 8.3%, 69.4%, and 22.2% of FL. Among biochemical, clinical, cytological, and echographic outcomes, altered thyroid autoantibodies, multiple versus single nodule, AUS versus FL, and presence of intranodular vascular flow were statistically significant to differentiate adenoma from carcinoma and from nonneoplastic lesions, whereas no significant differences were found between carcinomas and nonneoplastic lesions for these parameters. The results of this retrospective study show that undetermined FNAC category can further be subclassified in AUS and FL, the former showing higher malignancy rate. Further prospective studies are needed to confirm our results.

Do benign thyroid nodules have malignant potential? An evidence-based review

BACKGROUND

Benign thyroid tumors account for most nodular thyroid disease. Determination of whether a thyroid nodule is benign or malignant is a major clinical dilemma and underlies the decision to proceed to surgery in many patients. Although the accuracy of thyroid nodule fine-needle aspiration (FNA) has reduced the need for surgery over the years, questions regarding how to follow FNA-designated benign nodules remain unresolved. This is true at least in part because of uncertainty over whether some benign nodules harbor malignant potential.

METHODS

An evidence-based review of recent clinical, pathologic, and molecular data is presented. A summary of data and observations from our own experience is also provided.

RESULTS

Review of our recent 10-year experience indicates that 2% of thyroid malignancies arise within a preexisting benign thyroid nodule. In addition, both cytologic and molecular tumor markers, including Gal-3, CITED1, HBME-1, Ras, RET/PTC, and PAX8/PPAR gamma, have been identified in some histopathologically classified benign nodules. Gene expression profiling suggests that follicular adenomas and Hürthle cell adenomas have similarities to both benign and malignant tumors, suggesting that some of these tumors are premalignant. In addition, 10% of surgically excised follicular tumors are encapsulated follicular lesions with nuclear atypia, which have been termed "well-differentiated tumors of uncertain malignant potential." The data available suggest that these tumors could be precursors to carcinoma.

CONCLUSION

Some benign thyroid nodules have malignant potential. Further molecular testing of these tumors can shed light on the pathogenesis of early malignant transformation.

Contemporary diagnostic approach to the thyroid nodule

Thyroid nodules are common, with an estimated incidence of 5%-10% in the United States. The current gold standard for diagnosis is fine needle aspiration biopsy (FNAB). The incidence of indeterminate diagnoses varies from 10% to 25%. Surgical resection is usually indicated to exclude the diagnosis of cancer in these patients. However, only a minority (about 20%) of indeterminate thyroid nodules actually harbor a malignancy, resulting in surgery for diagnostic purposes alone in many patients. The increased detection of benign nodules and microcarcinomas reinforces the need for improved non-operative methods to differentiate benign from malignant disease and discriminate low-risk from high-risk cancers. In this article we present a current, rational diagnostic approach to the patient with a thyroid nodule, evaluate new advances including thyroid genomic and predictor models, and propose the development of prospective trials to incorporate these new additions into clinical decision making. Given how many questions still exist for patients with thyroid nodules, partnership and collaboration, or the "bench to bedside" concept should find its way into most every thyroid surgeon and endocrinologist's lexicon.

Solitary thyroid nodule: current management

Clinically, solitary thyroid nodules are common, being present in up to 50% of the elderly population. The majority are benign with thyroid cancer representing an uncommon clinical problem. Investigation should include careful history and examination and thyroid function tests. Toxic or autonomous nodules are rarely malignant and require radionuclide scan for assessment. If euthyroid, then fine needle biopsy provides direct specific information about the cytology of the nodule from which the histology can be inferred. Thyroid 'incidentalomas' are a common management problem. Non-palpable nodules greater than 1.0 to 1.5 cm represent an absolute indication to perform an ultrasound-guided fine needle biopsy. An atypical fine needle biopsy mandates formal diagnostic excision. Because it is not possible to distinguish a follicular carcinoma from a follicular adenoma on cytological grounds alone, this category must simply be interpreted as indicating a follicular tumour and up to 20% will be malignant. Hemithyroidectomy via a 'collar' incision, with submission of the specimen to formal pathological examination, remains the standard of care, with completion total thyroidectomy for cancers other than low risk papillary cancer and 'minimally invasive' follicular cancer without vascular invasion. The issue of whether follicular adenomas can potentially develop into follicular carcinomas has yet to be satisfactorily resolved. The major challenge in the management of the solitary thyroid nodule remains the assessment as to which nodules require surgical excision and which can be followed conservatively.

Evaluation of the thyroid nodule

BACKGROUND

Thyroid nodules are common, yet treatment modalities range from observation to surgical resection. Because thyroid nodules are frequently found incidentally during routine physical examination or imaging performed for another reason, physicians from a diverse range of specialties encounter thyroid nodules. Clinical decision making depends on proper evaluation of the thyroid nodule.

METHODS

The current literature was reviewed and synthesized.

RESULTS

Current evidence allows the formulation of recommendations and a general algorithm for evaluating the incidental thyroid nodule.

CONCLUSIONS

Only a small percentage of thyroid nodules require surgical management. Diagnosis and treatment selection require a risk stratification by history, physical examination, and ancillary tests. Nodules causing airway compression or those at high risk for carcinoma should prompt evaluation for surgical treatment. In nodules larger than 1 cm, fine-needle aspiration biopsy is central to the evaluation as it is accurate, low risk, and cost effective. Subcentimeter nodules, often found incidentally on imaging obtained for another purpose, can usually be evaluated by ultrasonography. Other laboratory and imaging evaluations have specific and more limited roles. An algorithm for the evaluation of the thyroid nodule is presented.

Thyroid cancer review 1: presentation and investigation of thyroid cancer

Thyroid cancer is uncommon with an estimated lifetime risk of 0.8% for women and 0.3% for men. The incidence appears to be increasing by 4% per year and is currently the eighth commonest cancer in women. Managing thyroid cancer is challenging, as no prospective randomised trials exist. Most of the information is derived from large patient cohorts in which therapy has not been randomly assigned. This is the first of the three review papers we have written on the management of thyroid cancer.

Contemporary management of thyroid cancer

Thyroid cancer is a relatively common and frequently curable malignant neoplasm, accounting for nearly 2% of all new cancers diagnosed annually in the United States. The diagnostic and management options have evolved considerably in the past decade, and a current understanding of these trends in the standard of care have assumed an important consideration in the practices of head and neck surgeons and endocrinologists alike. We sought to review the epidemiology and pathology of the several types of thyroid cancer and to present our evidence-based management algorithm. Every effort was made to offer alternative treatment strategies and supporting data where available. In addition to reviewing well-established approaches to diagnosis and management, emphasis is placed on newer techniques, including minimally invasive thyroidectomy, molecular detection of disease propensity, and the use of recombinant thyrotropin prior to radioiodine ablation.

Ultrasound thyroid nodule measurements: the "gold standard" and its limitations in clinical decision making

OBJECTIVE

To highlight the limitations associated with use of ultrasonography for the evaluation of thyroid nodule or gland volume for clinical decision making.

METHODS

We review the equipment (scanners and probes) used for ultrasonography and the appropriate measurements for assessment of thyroid nodules. The limitations of ultrasound thyroid measurements are summarized, particularly in reference to repeated measurements over time.

RESULTS

Thyroid ultrasonography is the recognized "gold standard" for an accurate and reliable assessment of gland volume and thyroid nodules. Many endocrinologists refer patients for surgical treatment because of detection of growth of thyroid nodules. In daily practice, they often make this decision by comparing ultrasound thyroid measurements determined over time. Although reliable, evaluation of thyroid nodule volume by ultrasonography has technologic, biologic, and examination technique limitations. These are particularly important in routine clinical practice, where ultrasound measurements are performed in less standardized settings than in experimental trials.

CONCLUSION

In daily medical office applications, ultrasound measurements of thyroid nodules should be used with caution in decision making.

Management of simple nodular goiter: current status and future perspectives

The simple nodular goiter, the etiology of which is multifactorial, encompasses the spectrum from the incidental asymptomatic small solitary nodule to the large intrathoracic goiter, causing pressure symptoms as well as cosmetic complaints. Its management is still the cause of considerable controversy. The mainstay in the diagnostic evaluation is related to functional and morphological characterization with serum TSH and (some kind of) imaging. Because malignancy is just as common in patients with a multinodular goiter as patients with a solitary nodule, we support the increasing use of fine-needle aspiration biopsy (cytology). Most patients need no treatment after malignancy is ruled out. In case of cosmetic or pressure symptoms, the choice in multinodular goiter stands between surgery, which is still the first choice, and radioiodine if uptake is adequate. In addition to surgery, the solitary nodule, whether hot or cold, can be treated with percutaneous ethanol injection therapy. If hot, radioiodine is the therapy of choice. Randomized studies are scarce, and the side effects of nonsurgical therapy are coming into focus. Therefore, the use of the optimum option in the individual patient cannot at present be based on evidence. However, we are of the view that levothyroxine, although widely used, should no longer be recommended routinely for this condition. Within a few years, the introduction of recombinant human TSH and laser therapy may profoundly alter the nonsurgical treatment of simple nodular goiter.

Multinodular goiter

MNG is a common clinical problem. Though most goiters are benign and asymptomatic, they may cause concern when they create compressive symptoms, develop autonomous functioning nodules, or form suspicious nodules. Diagnostic evaluation should include clinical evaluation, laboratory tests including TSH, and consideration of additional evaluation and imaging when there exists suspicion of complicating factors or risk of malignancy. In nontoxic MNG, suppression therapy or serial clinical exams and TSH values are appropriate in an asymptomatic, nonsuspicious goiter. In toxic MNG, treatment of the resulting thyrotoxicosis followed by RAI or surgery is indicated. When compressive symptoms, risk of malignancy, or cosmetic deformity develops, surgery also may be indicated.

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.

The thyroid and parathyroid glands. CT and MR imaging and correlation with pathology and clinical findings

Thyroid imaging approach is based on the preliminary clinical evaluation. Lesions that are smaller than 2 cm should be assessed with US, which is capable of discriminating masses as small as 2 mm and distinguishing solid from cystic nodules. US-guided FNAB provides tissue for cytologic examination of thyroid nodules. CT and MR imaging are indicated for larger tumors (greater than 3 cm diameter) that extend outside the gland to adjoining structures, including the mediastinum, and retropharyngeal region. Metastatic lymph nodes in the neck and invasion of the aerodigestive tract are also in the realm of CT and MR imaging. Thyroid nodules are categorized on scintigraphy as hot or cold nodules. Hot nodules are rarely malignant, whereas cold nodules have an incidence of 10% to 20% of malignancy. Calcifications (amorphous, globular, nodular, and linear) occur in adenomas and carcinomas and have no differential diagnostic features except for psammomatous calcifications, which are a pathognomonic finding in papillary carcinomas and a small percentage of medullary carcinomas. Papillary carcinoma is the most common malignant tumor (80%) followed by follicular (20% to 25%); medullary (5%); undifferentiated; anaplastic carcinomas (< 5%); lymphoma (5%); and metastases. Lymph node metastases are common in papillary carcinoma, 50% at presentation, and less common in follicular carcinomas. The metastatic nodes in papillary carcinoma may enhance markedly (hypervascular); show increased signal intensity on T1-weighted images (increased thyroglobulin content or hemorrhage); and reveal punctate calcifications. Localized invasion of the larynx, trachea, and esophagus occurs predominantly in papillary and follicular carcinomas; the incidence is less than 5%. Ectopic thyroid tissue may be encountered in the tongue (foramen cecum); along the midline between posterior tongue and isthmus of thyroid gland; lateral neck; mediastinum; and oral cavity. Goiter and malignant tumors, notably papillary carcinoma, may develop in ectopic thyroid tissue. Carcinomas may also arise in thyroglossal duct cysts, which develop from duct remnants between the foramen cecum and thyroid isthmus. Infectious disease of the thyroid gland is not common and the CT and MR imaging findings are similar as described under neck infection. Other types of inflammatory disorders including Hashimoto's thyroiditis, granulomatous thyroiditis, and Riedel's struma display no specific imaging features. Imaging studies may, however, be indicated to confirm a suspected clinical diagnosis and assess compromise of the airway (Riedel's struma). HPT is a clinical diagnosis in which hypercalcemia is the most important finding. Parathyroid hyperplasia, adenoma, and carcinoma represent underlying lesions. To relieve the patient's symptoms surgical extirpation is indicated. The surgical success rate without imaging is 95%. The indications for imaging studies vary but it is generally agreed that reoperation after a previous failed surgical attempt and suspicion of an ectopic parathyroid adenoma should be investigated by imaging. These consist of US, nuclear medicine studies, CT and MR imaging. US and technetium sestamibi scanning have the highest accuracy rate for localizing an adenomatous gland at and near the thyroid gland. Ectopic adenomas, particularly if they are located in the mediastinum, are preferrably investigated with CT and MR imaging with gadolinium and fat suppression. Carcinomas and parathyroid cysts are optimally evaluated by CT and MR imaging. On MR imaging adenomas are low in signal intensity on T1-weighted images, high in signal intensity on T2-weighted images, and enhance post introduction of gadolinium.

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.

Use of fine-needle aspiration cytology and frozen section examination in diagnosis of thyroid nodules

BACKGROUND

With the advent of fine-needle aspiration cytology (FNAC), the role of frozen section (FS) in the management of non-toxic thyroid nodules has become uncertain.

METHODS

During the period from January 1993 to December 1995, a total of 84 patients have undergone operative treatment for non-toxic thyroid nodules at the United Christian Hospital, Kowloon. The medical records of these patients were studied retrospectively.

RESULTS

In the benign group, the diagnostic accuracy of FNAC was 94% and that of FS was 91%. If FNAC reported malignancy, the diagnostic accuracy was 70%. If FS reported malignancy, the report was accurate in 100%. Among the 43 cases reported as benign on FNAC, FS did not alter the surgical management in any case. In 10 cases reported as suspicious on FNAC, FS altered the surgical treatment in one (10%). However, among the 10 cases reported as malignant on FNAC, FS subsequently altered the surgical management in five cases (50%). In three cases of malignancy on FNAC, both FS and the final histopathology report showed benign disease. Hence, FS avoided overtreatment in three patients.

CONCLUSION

Frozen section is indicated if pre-operative FNAC of the thyroid nodules suggests malignancy, in order to determine the extent of the operation and to avoid overtreatment of benign disease. However, FS can be omitted if FNAC is reported as benign or suspicious.

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.

Comparison of the results of diagnosis and treatment between solid and cystic well-differentiated thyroid carcinomas

We assessed the accuracy of ultrasonography and fine-needle aspiration cytology (FNAC) in diagnosing cystic thyroid cancer and compared the results with solid thyroid cancer patients. We also compared the results of treatment between these patient groups. We retrospectively reviewed 1013 thyroid cancer patients who received treatment at Chang Gung Memorial Hospital. For this study, 910 cases of papillary or follicular thyroid carcinomas were considered eligible. Of these, 682 patients received preoperative high-resolution ultrasonographic and FNAC examinations. The nodules of 583 (85.5%) patients were diagnosed as solid masses, 80 (11.7%) as mixed masses, and 19 (2.8%) as cystic masses. Of the 19 patients with cystic thyroid carcinoma, only 4 papillary thyroid carcinomas were diagnosed by ultrasonography with FNAC as malignant before operation. Six patients presented as occult thyroid carcinomas with the tumor size less than 1 cm. Despite the low rate of accurate diagnosis for the cystic malignancy, clinical staging and the survival rates were not statistically different when they were compared with the other groups. In conclusion, low diagnostic rates were observed in well-differentiated thyroid cancer with prospective ultrasound-guided FNA when lesions were cystic or in mixed lesions. If the solid portion of the cystic masses is aspirated under ultrasound-guided FNA and cytology is performed after the centrifugation of the aspirated fluid, diagnostic accuracy may be improved.

Clinical significance of clonality in thyroid nodules

BACKGROUND

Many different neoplastic and hyperplastic thyroid diseases present with clinically apparent thyroid nodules. Clonality analysis indicates whether a nodule arises from the polyclonal proliferation of a group of cells or forms a clone from a genetically altered cell and thus provides objective information on the origin of the thyroid nodules. Clonality was studied in thyroid nodules using the polymerase chain reaction (PCR) assay in the X-linked human androgen receptor (HUMARA) gene by random X chromosome inactivation in women.

METHODS

DNA samples were obtained from 28 nodules in 21 women. All nodules and non-tumour thyroid tissues were fractioned selectively under a cryostat. Genomic DNA was isolated and digested with HhaI. PCR amplification of the HUMARA locus was performed using PCR mixtures containing [alpha-32P]2'-deoxycytidine 5'-triphosphate. The PCR products were analysed by denaturing gel electrophoresis.

RESULTS

The HUMARA alleles were heterogeneous in 18 of 21 patients. Among the 23 nodules from 18 patients, all of the eight papillary thyroid carcinomas were monoclonal. Two solitary nodules from follicular adenomas were monoclonal. Of the 13 follicular nodules from nodular goitres, ten were polyclonal and three were monoclonal. The monoclonal follicular nodules were larger in size (3.5 versus 2.0 cm, P< 0.05) and had a tendency towards more cystic changes than polyclonal nodules.

CONCLUSION

PCR-based clonality study of thyroid nodules may help to distinguish hyperplastic from neoplastic nodules.

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.

Changing concepts in the diagnosis and management of thyroid nodules

Thyroid nodules are extremely common, affecting from 4% to 7% of the population. Fine-needle aspiration biopsy is the most accurate and cost-effective technique for nodule diagnosis. It is simple, safe, and should be the first test used in patient work-up. Routine thyroxine (T4) suppressive therapy is no longer recommended for cytologically benign nodules. T4 suppression can cause or aggravate osteoporosis, especially in postmenopausal women. New data on T4 suppressive therapy, cost analysis, and nodule guidelines are reviewed.

The epidemiology of thyroid disease and implications for screening

The burden of thyroid disease in the general population is enormous. As many as 50% of people in the community have microscopic nodules, 3.5% have occult papillary carcinoma, 15% have palpable goiters, 10% demonstrate an abnormal thyroid-stimulating hormone level, and 5% of women have overt hypothyroidism or hyperthyroidism. Despite this high prevalence of thyroid disease, screening for these disorders is not recommended by any major health agency. This article explores the epidemiologic issues surrounding this complex problem by analyzing prevalence, incidence, and mortality data from a worldwide variety of sources.

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.

Controversies in the management of cold, hot, and occult thyroid nodules

Some aspects of thyroid nodule evaluation and management remain controversial. Radionuclide scanning provides functional information about nodules and differentiates cold from hot nodules. Although thyroid cancers are cold on scan, most cold nodules are benign. Ultrasonography visualizes the thyroid gland and nodules with remarkable clarity and provides structural information about location, number, size, and consistency of nodules. Widespread application of ultrasonography has resulted in the frequent discovery of incidental (occult) nodules in the general population. The clinical significance of these nodules remains unknown, and their management has created a dilemma for physicians. Current cost-effective evaluation of nodules does not include scanning or ultrasonography as routine frontline tests. In most centers, fine-needle aspiration biopsy has supplanted imaging studies as the routine initial procedure for differentiating benign from malignant nodules. Cytologic diagnosis is reliable and inexpensive, and it results in a better selection of patients for surgery. Limitations include false-negative diagnoses, nondiagnostic results, and indeterminate "suspicious" results. Laboratory test results are usually normal, but determination of serum thyrotropin may identify a hot nodule, and plasma calcitonin may help diagnose medullary thyroid carcinoma. Treatment of thyroid nodules is controversial. In some practices, benign colloid nodules are treated with suppressive doses of levothyroxine. Recent reports cast doubt on the efficacy of this approach, and it is no longer acceptable to select patients for surgical treatment on the basis of suppressive therapy. Furthermore, suppressive levothyroxine therapy may be associated with significant bone and cardiac side effects, especially in elderly patients and postmenopausal women. Our approach is observation for most patients, and we suggest a careful risk-benefit analysis when suppression is considered. Hot (autonomous) nodules can be treated with radioiodine, surgery, or ethanol injection. The use of sensitive thyrotropin assays has revealed that the "euthyroid" hot nodule is often associated with subclinical hyperthyroidism, warranting treatment if risks of osteoporosis are significant. Small (< 1.5 cm) occult nodules can be observed. Larger (> 1.5 cm) nodules can be selectively evaluated by ultrasonographically guided fine-needle aspiration. It is prudent to consider cost of care, risk-benefit analysis, and the low incidence of malignancy in thyroid nodules when diagnostic tests are selected and the treatment plan is outlined.

The role of thyroid fine needle aspiration (FNA) cytology in a District General Hospital setting

The pilot study was undertaken to evaluate the role of FNA cytology in the clinical management of patients with thyroid swelling, in a District General Hospital (DGH) setting. One hundred and eleven patients were investigated over a period of 3 years, with a total of 142 fine needle aspirations. Statistical analysis showed a sensitivity of 71%, a specificity of 91% and a false negative rate of 2.7%. These results compare very favourably with other institutions. This study therefore shows that thyroid nodule FNA cytology can be performed in a DGH with a high standard of diagnostic accuracy, the results of which play a key role in patient management.

Management of thyroid nodules during pregnancy

Guidelines for the management of thyroid nodules discovered during pregnancy have not yet been established. The authors reviewed the records of 23 patients with thyroid nodules that were first detected during pregnancy. These patients were divided into three groups according to how they were managed. Seven patients who presented early in pregnancy had their work-up completed during pregnancy, 11 patients underwent biopsy after delivery, and 5 patients were managed with observation alone. The incidence of malignancy in the series was 39%. Four patients underwent surgery during pregnancy, and 7 patients were operated on in the postpartum period. No fetal morbidity or mortality occurred. The authors recommend that fine-needle aspiration be performed in patients who present before 20 weeks of gestation with rapidly enlarging thyroid nodules, nodules associated with palpable cervical adenopathy, solid nodules larger than 2 cm, or cystic nodules larger than 4 cm. Growth of a nodule while a patient is receiving thyroid hormone suppression therapy is highly suspicious for malignancy; in this situation, consideration should be given to performing biopsy later in gestation.

Current evaluation of thyroid nodules

Thyroid nodules are common and frequently benign. Current evaluation by fine-needle aspiration (FNA) biopsy is efficacious and cost-effective. Results of FNA series confirm that this procedure is safe, without serious complications, reliable, and relatively easy to perform. Radioisotope scanning and high-resolution ultrasonography are used in special circumstances and not as routine diagnostic tests. When FNA biopsy is applied, benign nodules (75%) are followed medically, and suspicious (20%) or malignant (5%) nodules are excised surgically. Overall, FNA biopsy of thyroid nodules has improved surgical selection, resulting in a 25% reduction in thyroidectomies for benign nodules.

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.

Preoperative diagnostic tests for operable thyroid disease

Although the availability and acceptance of fine-needle aspiration biopsy (FNAB) of thyroid nodules has increased, many physicians still use thyroid scintigraphy for distinguishing benign from malignant lesions. We evaluated these diagnostic tests in 350 patients who had thyroid surgery in our institution between 1977 and 1990. Histologic confirmation of FNAB was obtained in 265 patients. In the group of patients having surgery, 247 thyroid scintigraphies were performed. Our patients were divided into two groups (1977-1986 and 1986-1990). The first group comprised 173 patients with 173 FNABs and 126 scintigrams. The second group consisted of 177 patients having 92 FNABs and 121 scintigrams. Results of scintigrams were analyzed in the second group only. In 5 out of 120 cases where the FNAB result was "benign or probably benign" the lesion appeared to be malignant postoperatively. If the FNAB result was "malignant or probably malignant" (n = 83) the pathology report confirmed a malignancy in 68 cases (81.9%). In 56 instances of all 265 FNABs the cytology report was not conclusive ("uncertain"); in 21.4% of these cases a malignancy was found postoperatively. An FNAB-result "(probably) malignant" had a positive predictive value of 0.819 while the negative predictive value of a result "(probably) benign" is 0.950. An "uncertain" result does not take away our concern so this result should have the same consequences as those of a result "(probably) malignant". In that case, FNAB-sensitivity is 93.0% and specificity 66.1%. Eighty-five of the last 116 scintigraphies showed a solitary node. Eleven of these nodes were hot while 74 were cold.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of subclinical hyperthyroidism and relationship between thyroid hormonal status and thyroid ultrasonographic parameters in patients with non-toxic nodular goitre

OBJECTIVE

Basal plasma T4, T3 and TSH concentrations are usually normal in patients presenting with non-toxic nodular goitre. Using the evaluation of TSH response to TRH in a large series of such patients living in an area with normal iodine intake, we evaluated the prevalence of subclinical hyperthyroidism and the relationship between thyroid hormonal status and ultrasonographic parameters.

PATIENTS

A prospective study of 242 consecutive patients (group I), referred with non-autoimmune nodular goitre, normal plasma free T4, total T3 and TSH levels, without (subgroup IA, 222 patients) or with (subgroup IB, 20 patients) clear-cut autonomous area(s) on scintigraphy. These patients were compared to 135 controls (group II).

MEASUREMENTS

Plasma free T4 (FT4), total T3 (T3T) and TSH measurements. Evaluation of TSH response to TRH (delta level of increased TSH = peak TSH level during TRH test-basal TSH level), thyroid scintigraphy and morphological characteristics (number and total volume of nodule(s) and volume of extranodular tissue) determined by ultrasonography.

RESULTS

In subgroup IA, (1) the mean (+/- SEM) basal TSH level (0.94 +/- 0.04 mU/I) and the mean value of increased TSH after TRH (4.92 +/- 0.34 mU/I) were lower (P < 0.001) than in group II (1.28 +/- 0.05 mU/I and 7.24 +/- 0.25 mU/I, respectively). The prevalence of SH (delta level of increased TSH below the mean -3 SD in controls) was 17.2%; (2) the mean FT4 level and the mean T3T value were not different (P > 0.05) from those of group II. In subgroup IB, (1) the mean basal TSH level (0.57 +/- 0.11 mU/I) and the mean increment of TSH after TRH (2.81 +/- 0.62 mU/I) were lower (P < 0.001) than in subgroup IA. The prevalence of subclinical hyperthyroidism was 75.0%; (2) the mean FT4 level (17.2 +/- 0.9 pmol/I) was not different from that in group II. However, the mean T3T value (1.99 +/- 0.01 nmol/I) was higher (P < 0.001) than in group II (1.65 +/- 0.05). In group I, subgroup IA and IB, there were significant (P < 0.05, at least) correlations between the numbers of nodules and both basal TSH levels and delta values of increased TSH or FT4 levels or T3T values. No correlations were found between other ultrasonographic data and plasma thyroid parameters.

CONCLUSIONS

This study demonstrates a high prevalence of subclinical hyperthyroidism in patients presenting with non-toxic nodular goitres and suggests that the number of nodules, but not their total volume, is an important factor in the development of this condition.

Observer variation in ultrasound assessment of the thyroid gland

In order to determine observer variation in the assessment of the thyroid gland by ultrasonography, two specialists (one endocrinologist and one radiologist) independently evaluated 76 thyroid glands, and assessed the sonogram as homogeneous, inhomogeneous, containing a solitary solid lesion or a solitary cyst in each of 152 thyroid lobes. The observed agreement between the two observers ranged from 0.80 to 0.91. By the use of the kappa coefficient the observed agreement was adjusted for change agreement. Kappa can vary from -1 (total disagreement) to +1 (total agreement) and kappa values between 0.55 and 0.60 were found. Among 152 lobes a solitary solid lesion, i.e. a nodule, was found in 22 lobes by the two observers; however, they only agreed on a classification in 10 lobes (45%). Clinicians should be aware of the moderate agreement between observers in thyroid ultrasonography.

Thyroid cancer

Management of thyroid cancer varies somewhat between communities and institutions depending on tumor type and individual treatment philosophy. The differentiated thyroid cancers have a significantly better outlook than the medullary and anaplastic. This article provides an overview of the literature that describes pathogenesis, diagnosis, and treatment currently recommended for these thyroid cancers.

Suppressive therapy with levothyroxine for solitary thyroid nodules

OBJECTIVE

To evaluate the effect of treatment with TSH suppressive dose of levothyroxine in patients with benign thyroid nodules.

DESIGN

Prospective randomized study. Group A (n = 20) patients received levothyroxine and group B (n = 20) patients did not. The dose of levothyroxine was adjusted to obtain an effective suppression of TSH. A clinical, analytical and morphological (with ultrasound) review was performed every 3 months. The mean +/- SD follow-up period was 10.6 +/- 2.2 months.

PATIENTS

Forty euthyroid women with solitary thyroid nodule on palpation, cold on scintigraphy and cytologically benign without contraindication participated.

MEASUREMENTS

At entry: biochemical and hormonal parameters, thyroid scintigraphy and thyroid ultrasonography. Every 3 months additional determinations of thyroid hormones and TSH levels were carried out, if necessary, to verify effective TSH suppression. Every 6 months thyroid ultrasound imaging was performed.

RESULTS

Patients were euthyroid at entry into the study. The mean dose of levothyroxine necessary to obtain TSH suppression was 2.82 +/- 0.6 micrograms/kg/day. No significant modification in the thyroid nodule diameter (mean +/- SD 2.6 +/- 1.2 vs 2.5 +/- 1.2 cm) or in the thyroid nodule volume (10.3 +/- 11.9 vs 10.1 +/- 12.2 ml) were observed in group A. In group B the results were similar (2.8 +/- 0.9 vs 2.7 +/- 1.8 cm and 9.2 +/- 6.4 vs 9.2 +/- 9.5 ml, respectively). No differences were found in either group in the number of nodules that reduced significantly their volume (four and three, respectively).

CONCLUSIONS

The suppressive therapy with levothyroxine was not effective in reducing nodule sizes in patients with solitary benign thyroid nodules.

Modern methodologies of differentiating thyroid masses

The rational treatment of thyroid diseases requires an understanding of the thyroid function and an accurate evaluation of its functional (endocrine), as well as it morphological alteration. There are several different imaging techniques which are available and are in use in the evaluation of thyroid diseases. In this article we present a protocol for the use of diagnostic imaging to evaluate a focal thyroid mass, a diffusely enlarged gland, regional, and distant metastatic disease. The current diagnostic applications of radionuclide scanning, ultrasound, computed tomography, and magnetic resonance imaging (MRI) will be discussed.

Evaluation of thyroid nodules

The first consideration in evaluating the thyroid nodule is whether it is functioning and causing hyperthyroidism. Autonomous nodules should be treated with either surgery or I-31, with surgery favored due to the possibility, although small, of malignancy. Thyroid scans are no longer recommended during the initial evaluation of the thyroid nodule. Ultrasound is useful in determining the size of the nodule and whether it is multinodular thyroid disease, but it cannot detect thyroid cancer. Fine needle aspiration biopsy is currently the procedure of choice for evaluating all thyroid nodules. For accuracy of the cytological analysis, it is important that adequate tissue samples be obtained. False negative findings are of most concern to the clinician and occur in 2-10% of reported fine needle aspiration biopsy series. Nodules thought to be benign will need continued follow-up.

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.

Descriptive epidemiology of thyroid cancer in the Swiss Canton of Vaud

Although substantial decreases have been recorded, age-standardized mortality rates from thyroid cancer in Switzerland are still the highest in Europe in men (0.9/100,000), together with those from Austria, and the third highest (1.0/100,000) in women. Detailed analysis of 308 new cases registered between 1974 and 1987 in the Swiss Canton of Vaud revealed an overall incidence rate of 1.36/100,000 men (world standard) in 1974-1980 and of 1.74/100,000 in 1981-1987. Corresponding values for women were 4.28 and 4.51, respectively. Thus, women constituted the majority of all cases (76%). Papillary carcinoma was the most frequent histological type (53%) followed by follicular (27%), undifferentiated (5%) and medullary (2%); other morphologies and clinical tumours accounted for 13% of the whole series. In both sexes, most of the apparent increase over the calendar period was restricted to the papillary type. Overall 5- and 10-year survival rates were 71% and 57%. When various factors were introduced in a Cox proportional-hazard model, young age at diagnosis (hazard rate for greater than or equal to 65 years vs less than 45 = 14.7; 95% confidence interval = 7.5-29.1) and good histological differentiation (hazard rate for papillary and follicular vs undifferentiated = 0.4) emerged as strong favourable and independent prognostic factors. The reduced hazard rate for women, other factors being equal, was of borderline significance (0.7, 95% confidence interval = 0.5-1.0), whereas no significant difference was observed between follicular and papillary carcinomas, and calendar periods of diagnosis.

Observer variation in the scintigraphic diagnosis of solitary cold thyroid lesions

In order to evaluate the reproducibility of the diagnosis of solitary cold thyroid lesions, two specialists in nuclear medicine and two specialists in endocrinology independently twice read 240 thyroid 99mTc pertechnetate scintigrams. No significant difference or interaction between the results obtained from the right and the left lobe was found. A solitary cold lesion was diagnosed in 100 of the 480 lobes; however, in only 30 did all four observers agree upon the diagnosis. Interobserver variation was determined by pairwise comparison of observers. The observed agreement was between 0.91 and 0.94. After adjusting for expected chance agreement, kappa values between 0.57 and 0.70 were found. Intraobserver variation was smaller than interobserver variation, revealing agreement rates of 0.93-0.96 and kappa values between 0.71 and 0.77. Agreement was related to large lesions, lesions located centrally in the lobe, and ovoid-shaped lesions. Clinicians should be aware to what extent they can rely on the information they use in their decisions. The considerable inconsistency in the evaluation of cold lesions on thyroid scintigrams should be taken into consideration, and calls in question the value of using thyroid scintigrams for deciding whether a patient should be referred for operation or biopsy.