Fine Needle Aspiration in the Management of Thyroid Nodules: Experience at King Khalid National Guard Hospital, Jeddah

Abstract

Brief ReportsFine Needle Aspiration in the Management of Thyroid Nodules: Experience at King Khalid National Guard Hospital, Jeddah Layla Abdullah, FRCPC, MIAC J. Thomas, and FRCPath (UK) R. FadaqMD Layla Abdullah Correspondence to: Dr. Layla S. Abdullah, Department of Pathology, King Khalid National Guard Hospital, P.O. Box 9515, Jeddah 21423, Saudi Arabia From the Department of Pathology, King Khalid National Guard Hospital, Jeddah, Saudi Arabia Search for more papers by this author , J. Thomas From the Department of Pathology, King Khalid National Guard Hospital, Jeddah, Saudi Arabia Search for more papers by this author , and R. Fadaq From the Department of Pathology, King Khalid National Guard Hospital, Jeddah, Saudi Arabia Search for more papers by this author Published Online:1 Nov 2003https://doi.org/10.5144/0256-4947.2003.408SectionsPDF ToolsAdd to favoritesDownload citationTrack citations ShareShare onFacebookTwitterLinked InRedditEmail AboutIntroductionNodular thyroid diseases are common, especially in mountainous areas of the western region of Saudi Arabia.1 These nodules often present a diagnostic dilemma clinically as the distinction between benign and malignant lesions is not always obvious, making immediate planning of appropriate management difficult. Fortunately, the majority of these thyroid nodules are benign. Most are nodular goiter, which must be accurately distinguished from thyroid cancer. Thyroid cancer constitutes 5.4 % of all cancers in Saudi Arabia and is the second commonest cancer in females, with an age standardization rate of 3.5 per 100 000.1Many techniques are available for use in the diagnosis of thyroid nodules, but they are expensive and associated with high morbidity rates. Fine needle aspiration (FNA) cytology is considered a minimally invasive, quick, cheap, effective and accurate primary mode of screening, diagnosing, and triaging patients with thyroid diseases.2-4 Occasionally, this technique can be therapeutic, especially in cytic lesions.In this report, we review our experience with this technique over a 4-year period at the King Khalid National Guard Hospital (KKNGH), Jeddah, to assess its usefulness and diagnostic accuracy in the management of thyroid nodules in our center.MATERIALS AND METHODSThe records of all FNA of thyroid nodules received in the Pathology Department at KKNGH, Jeddah, between January 1997 and December 2000 were retrieved and reviewed. The aspirations were carried out using either a 23G or 25G gauge needle attached to a 10 cc syringe with or without the use of the syringe holder. The aspirates were immediately smeared on standard microscope slides and either air-dried and stained with Diff-Quick stain or fixed in 95% alcohol and stained with Papanicolaou stain. The adequacy of each aspirate was assessed at the time of aspiration, on site and insufficient aspirates were immediately repeated. A maximum of 3 to 4 aspiration attempts were often performed on a patient during any clinic attendance to avoid haematoma formation. If repeated aspirates were still insufficient, the patient was given a 2 to 3 week appointment for a repeat FNA, or referred for ultrasound-guided aspiration, especially for nodules that are small, ill-defined or deep-seated.The cytological smears were reviewed microscopically and classified as either (1) benign (nonneoplastic), (2) follicular neoplasm, (3) indeterminate, (4) malignant or (5) inadequate. Indeterminate smears included cases in which hyperplastic nodules could not be differentiated from follicular neoplasm. Attempts were also made to classify the malignant lesions into follicular, papillary and medullary carcinoma or lymphoma.Cases that had subsequent follow-up surgical resections were extracted from the record and their histological diagnoses were reviewed and correlated with their cytological diagnoses. The demographic data of all patients were extracted from the requisition forms and reports. The specificity, sensitivity and positive predictive value of the procedure were determined.RESULTSA total of two hundred and fifty three cases of thyroid FNA were seen during the 4-year period and most were performed by the pathologists during the regular weekly FNA clinic. There were 225 females and 28 males and the ages ranged from 12 to 80 years with an average of 55 years. The peak age range of occurrence of thyroid nodules was 30 to 49 years, with this age group constituting 58.5 % of the cases.Benign non-neoplastic lesions accounted for 56.5% (143 cases) with the majority, 51.8 % (131 cases) diagnosed as benign nodular goiter. Hashimoto’s thyroiditis was present in 12 cases. Definite diagnosis of papillary carcinoma was made in 10.7 % of the cases. No case of lymphoma, medullary carcinoma or anaplastic carcinoma was detected in this series. Cases diagnosed as follicular neoplasms and indeterminate lesions constituted 51 (20.2%) and 15 (5.9%) of cases, respectively. Insufficient specimens accounted for 17 (6.7%) cases.Table 1 shows the cytological and histological correlation of the 74 cases that had follow-up thyroidectomy. The sensitivity and specificity was determined to be 89% and 92%, respectively. There was good correlation amongst the benign cases with only one false negative case. The majority of cases reported cytologically as follicular neoplasms were follicular adenoma (24 cases) and only 4 cases were well-differentiated minimally invasive follicular carcinoma. Seven cases were subsequently diagnosed as follicular variant of papillary carcinoma. The only case classified as indeterminate on cytology was found to be multinodular goiter on histology. The two false positive cases were found to have benign goiter on histological analysis.Table 1. Cytohistological correlation of 74 cases with thyroid FNA + histology.Table 1. Cytohistological correlation of 74 cases with thyroid FNA + histology.DISCUSSIONKing Khalid National Guard Hospital, a 500-bed tertiary center, serves Saudi Arabian National Guard members and their dependents, in addition to the general population through the Emergency Department of our private business center. A regular FNA clinic is run by the Anatomic Pathology Department where pathologists perform FNA on patients referred from other departments.FNA has been extensively documented as a useful and reliable technique in the assessment of thyroid nodules, with specificity and sensitivity rates varying from 75 to 100 % in various reports.2-4 The specificity of 92% and the sensitivity of 89% achieved in our study correlates with reports of other studies establishing that FNA of thyroid is a safe, reliable and effective method for differentiating benign from malignant nodular thyroid lesions in our center. The performance and organization of the FNA clinic by pathologists and strict specimen adequacy rules have proved to be useful and likely responsible for the high sensitivity and specificity achieved. In our clinic, specimen adequacy is assessed immediately and FNA is repeated at a single attendance whenever an insufficient specimen is detected. This approach ascertains adequate sampling and superb technical quality while limiting the number of unsatisfactory aspirates.In various reports, up to 10 % of FNAs are considered indeterminate and these are usually due to overlapping cytological features between adenomatous hyperplastic nodules and follicular neoplasms.5-7 In our series, only 15 cases (5.9%) were classified as indeterminate. Another major limitation encountered is differentiating follicular adenoma from minimally invasive well-differentiated follicular carcinoma. Although many studies have tried to correlate cytological features, such as cell size, and nuclear overlapping, and clinical features such as nodule size, age > 40 years and male sex, none of these has been found to be consistently reliable.7 This difficulty in reliable differentiation of follicular adenoma from low-grade follicular carcinoma by FNA is highlighted in this series; 4 cases classified as follicular neoplasm were subsequently diagnosed as low-grade follicular carcinoma. Fortunately, the management of these lesions does not differ significantly. Of note, however, is that 24 of the 35 cases (68.5%) cytologically categorized as follicular neoplasm were accurately diagnosed as true follicular neoplasm (20 adenoma and 4 carcinoma). Careful evaluations of cases with features of follicular lesion have been instituted to limit this, but these problems still remain difficult. The two false positive cases turned out to be nodular goiter, which highlights the difficulty in distinguishing between the papillary hyperplastic foci of nodular goiter and carcinoma. Using strict cytological nuclear criteria of papillary carcinoma can help to eliminate this problem.In conclusion, our study confirms other reports that FNA of thyroid is a safe, reliable and effective method for differentiating benign from malignant thyroid nodules. The skillful application of FNA technique with recovery of adequate sample by on site evaluation of the cytological preparation will decrease interpretative errors and significantly improve the diagnostic accuracy of thyroid FNA. Surgeons also use the information provided on FNA in triaging and counseling patients prior to surgical intervention and planning subsequent management.*% sensitivity = 8/8+1 × 100 = 89%; 25/25+2 × 100 = 98%. The true negative includes 24 goiters and 1 case diagnosed as indeterminate; follicular adenoma was considered negative.ARTICLE REFERENCES:1. Kingdom of Saudi Arabia, Ministry of Health. "National Cancer Registry Cancer Incidence Report" . Saudi Arabia; 1997-1998. Google Scholar2. Piromalli D, Martell G. "The role of fine needle aspiration in the diagnosis of thyroid nodule: Analysis of 795 consecutive cases." J Surg Oncol.. 1992; 50(4):247-250. Google Scholar3. Thomas JO, Adeyi OA. "Fine needle aspiration cytology in the management of thyroid enlargement: Ibadan experience." East African Med J.. 1998; 75(11):656-660. Google Scholar4. Al-Rikabi AC, Al-Omran M. "Pattern of thyroid lesions and the role of fine needle aspiration cytology: a retrospective study from a teaching hospital in Riyadh." APMIS.. 1998; 106(11):1069-1074. Google Scholar5. Bakhos R, Selvaggi . "Fine needle aspiration of the thyroid: Rate and causes of cytohistopathologic discordance." Diag Cytopathol.. 2000; 23(4):233-237. Google Scholar6. Sidawy MK, Del Vecchio . "Fine needle aspiration of thyroid nodules: Correlation between cytology and histology and evaluation of discrepant cases." Cancer.. 1997; 25:(4)253-259. Google Scholar7. Baloch ZW. "Diagnosis of follicular neoplasm: A gray cone in thyroid FNA cytology." Diag Cytopathol.. 2002; 26(1):41-44. Google Scholar Previous article Next article FiguresReferencesRelatedDetails Volume 23, Issue 6November-December 2003 Metrics History Accepted1 April 2003Published online1 November 2003 InformationCopyright © 2003, Annals of Saudi MedicinePDF download