INTRODUCTION• Thyroid nodules - common clinical findings - prevalence - 4% to 7% of adult population.• Common in women.• Incidence ↑’s- Age, h/o radiation exposure and a diet containing goitrogenic material.• Commonest enlargement- Adenomatous and colloid goiters.• Especially- iodine deficient goiter belt areas.• .Prevalence- 40%.
• Difficult by clinical evaluation alone to make a correct diagnosis. Hence it is essential that correct diagnosis is made as early as possible.• FNAC- simple, safe, minimally invasive, reliable outpatient procedure.• Performed in children, adults, aged and pregnant women.• First line of investigation in goiters and a reliable procedure to obtain accurate diagnosis avoiding diagnostic surgery.
AIMS AND OBJECTIVES• To study the advantage of FNAC as a simple procedure for the diagnosis of goiter and to utilize it on the patient’s first visit to the hospital.• To compare the preoperative FNAC with postoperative histopathology and to determine the diagnostic accuracy of this test in the diagnosis of goiter.• To study the age and sex incidence of goiter and to study the geographical distribution of the lesion.
MATERIALS AND METHODS• A prospective study was conducted at ASRAMS hospital, Eluru from June 2010 to May 2012.• 221 patients between ages of 10-60 years with clinical presentation of simple and nodular goiters were selected for FNAC. There was no sex distinction.• These cases comprised of a heterogenous population from various areas of West godavari & Krishna districts.• All the patients underwent complete history taking, physical examination and hormonal assay.
• Careful palpation of the thyroid was done to guide precisely the location for doing aspiration.• Details of the procedure were explained to the patients.• Aspiration was done with the patient lying comfortably in a supine position and the neck was extended with a pillow under the shoulder so as to make the thyroid swelling appear prominent.• Under aseptic precautions 23 gauge needle was inserted into the lesion without attachment of a syringe and to and fro movement performed quickly.
• The material gets collected in the bore by capillary suction. The needle hub was attached to air-filled syringe and the plunger was pushed down to expel the material onto a clean, labeled glass slide.• The same procedure was repeated at different sites depending on size of the swelling.• Several smears were made in each case, fixed in 95% ethyl alcohol and stained by H&E method and Pap method, other was air dried and stained with MGG stain.
• Out of 221 patients, 76 patients underwent surgeries like hemithyroidectomy, subtotal and near total thyroidectomies.• Histopathological examinations of these specimens were also done.• All the specimens were fixed in 10% formalin. Detailed gross examination was done and 3-10 tissue bits were selected from representative areas and all the bits were processed and stained with H&E stain.• Cytological diagnosis was correlated with histopathology and the efficacy of FNAC was estimated.
RESULTS AND OBSERVATIONS• Study design: The present study deals with the fine needle aspiration cytology of simple and nodular goiters and determination of diagnostic accuracy of aspiration cytology.• A total of 221 patients with clinical presentation of goiters were subjected to FNAC during a period of 2 years from june 2010 to may 2012.• Of these 76 patients underwent surgery subsequently and histopathological examination of the excised specimens was done.
• Pre-operative diagnosis by FNAC was compared with histopathology reports of the operative specimens.• The important observations of the study have been represented in tabular and graphial forms.
• Cyto-histological concordance in the diagnosis of goiter is 95.7%.(68/71 cases).• Analysis of the FNAC results obtained were compared with the histological findings in the cases of goiter yielded the following diagnostic values:• Sensitivity- 100%.• Specificity- 62.5%.• Positive predictive value- 95.7%.• Negative predictive value- 100%.• Diagnostic accuracy- 96.05%.
Fig 1: Colloid goiter. Abundant thick colloid with fewclusters of follicular epithelial cells(H&E, scanner view)
Fig 2: Colloid goiter. Varying sized follicles lined by flattened epithelium filled with colloid (H&E,x 10)
Fig 3: Nodular colloid goiter. Clusters and sheets of follicular cells with colloid background(H&E, x10)
Discussion• Thyroid nodules are a common clinical problem.• In iodine deficient areas the incidence of goiters among thyroid nodules is much higher.• An accurate and reliable diagnosis of goiter is thus important to avoid unnecessary surgeries and impose burden on the healthcare system.
• The present study deals with the fine needle aspiration cytology of goiters in 221 patients of which 76 of them underwent surgery subsequently.• The results of the patients were compared wherever available to determine the diagnostic accuracy of FNAC in the diagnosis of goiter.
Table 17: Comparison of AgeStudies Range of age Median age in years in yearsMahar et al 13-76 39Mubarik et al 20-60 41Saddique et al 10-70 35Basharat et al 10-70 33Handa et al 5-80 37Present study 10-70 35
Table 18: Comparison of SexStudies Total Males Females M:F ratio casesMubarik et al 54 7 47 1:6.7Safirullah et al 300 30 270 1:9Saddique et al 60 8 52 1:6.5Haberal et al 260 42 218 1:5Handa et al 434 - - 1:6.3Present study 221 10 211 1:21
Table 19: Comparison of Age and Sex for Simple and Nodular goiterStudies Median age in Female to Male years ratioHanda et al 39 6:1Charugupta et al 32 7:1Present study 27 17:1
Table 20: Comparison of TSH levelsStudies Normal Decreased Increased TotalBasharat et al 48 2 0 50Godinho- 109 11 4 124Matos et alHanda et al 80 25 15 120Present 177 31 13 221study
Table 21: Comparison of Presenting SymptomsStudies Swelling Pain Dysphagia Palpitation Weight Total front of & Anxiety gain neckGodinho- 144 8 11 11 4 144Matos et alHanda et al 434 10 6 15 6 434Present 221 3 6 27 11 221study
Table 22: Comparison of Size of the Swelling Studies 1-5cm 6-10cm Total Basharat et al 35 15 60 Present 157 64 221 study
Table 23: Comparison of lesions on FNACStudies Benign Follicular Malignant Inadequate TotalHanda et al 381 14 17 22 434Charugupta 470 _ 30 7 507et alBagga & 228 17 3 4 252MahajanMahar et al 63 44 15 3 125Present 204 10 5 2 221study
Table 24: Comparison of Individual Lesions on CytologyDisease Nongrum Bhatta et al Mosawi et Mubarik et Present study et al n=60 n=90 al n=78 al n=54 n=76Simple & Nodular 34 58 52 38 40colloid goiterNodular goiter with 0 13 4 5 28cystic degenerationHyperplastic goiter 4 0 6 0 3Hashimoto’s 14 6 3 1 2thyroiditisFollicular neoplasm 5 3 3 7 2Papillary 2 9 4 1 1carcinomaAnaplastic 1 1 0 0 0carcinomaUndifferentiated 0 0 0 2 0carcinomaSuspicious 0 0 3 0 0Non diagnostic 0 0 3 0 0
Table 25: Comparison of Cyto-HistologicalConcordance in the Diagnosis of Goiter Studies No. % Mathur et al 130/134 97 Schnurer et al 264/284 93 Hag et al 32/35 91.4 Saddique et al 29/30 96.7 Mubarik et al 40/43 93 Present study 68/71 95.7
Table 26: Comparison of False Negativity Rate Studies No. of FN cases FNR Mahar et al 6/125 3.78% Mathur et al 9/154 5.8% Saddique et al 3/60 5% Mubarik et al 1/54 1.85% Haberal et al 6/260 2.3% Bhatta et al 1/20 5% Present study 3/76 3.95%
• False negative rates reported in literature range from 1.5 to 9%.• The false negative FNAC results may occur because of: -Inadequate samples. -Geographic misses of lesion. -Dual pathology and errors of interpretations. -Presence of cystic neoplasm.
• Intermediate FNAC results and cytodiagnostic errors are unavoidable due to overlapping cytological features, particularly among hyperplastic adenomatoid nodules, follicular neoplasms and follicular variants of papillary carcinoma.
Table 27: Comparison of diagnostic values in goiterStudies Sensitivit Specificity Positive Negative Diagnostic y predictive predictive accuracy value valueNongrum et 100% 50% 75% 100% 80%alBeneragama 82.25% 87.77% 82.25% 87.25% _et alPresent study 100% 62.5% 95.7% 100% 96.05%
CONCLUSION• It is concluded that FNAC is a simple, minimally invasive first line diagnostic procedure for evaluation of simple and nodular goiter with significant efficacy in differentiating malignant from benign lesions of thyroid.• FNAC thus is a fairly accurate and reliable modality for diagnosis of goiters and is a very useful tool to select patients who would require surgery, thereby reducing unnecessary surgeries.• Strict adherence to adequacy criterion and meticulous examination of all the smears are of paramount importance in achieving a high rate of diagnostic accuracy.
• FNAC is highly sensitive and specific diagnostic procedure. But it can give false negative result. So final diagnosis and treatment pattern should be based upon histopathology.• This study also concludes that these areas are endemic for thyroid disease as goiter is common presentation. It is because of low intake of iodized salt. Medical education should be given in these areas.