Fine needle aspiration of thyroid nodules at Surin Hospital

Abstract

Background: Thyroid nodules are common in clinical practice. They may be solitary within a normal thyroid gland or dominant within a multinodular goiter. The incidence of thyroid noduleร has been on the rise in recents decades, mainly due to the wider use of neck imaging. Therefore, the incidental finding of a thyroid nodule in an asymptomatic patient is not rare. The differential diagnosis of a thyroid nodule is crucial, as malignancy necessitates surgery, while strict patient follow up is necessary in the case of benignancy. Fine needle aspiration biopsy (FNAB) is considered to be the "gold standard" in the selection of patients for surgery.
Objective: To study comparision between preoperative FNAB cytopathologic reports and postoperative histopathologic reports, and to study the application, reliability and efficacy of FNAB comparing with that of other reports.
Setting: Fine needle aspiration unit, Department of Otorhinolaryngology, Surin Hospital.
Research design: Retrospective study.
Materials: 110 patients who underwent thyroidectomy by the author after FNAB at Surin Hospital from June 2003 - December 2007 were included in the study.
Interventions: Preoperative FNAB cytopathologic testing and thyroidectomy and postoperative histopathologic testing.
Main outcome measures: Preoperative cytopathologic reports were compared with post thyroidectomy histopathologic reports.
Results: 110 patients were studied. Female to male ratio was 11.5 : 1 Age of the patients ranged from 20 to 70 years with mean age 43.55 years (SD. 9.81). On preoperative FNAB reports, 8 cases (7.27%) were declared as papillary carcinoma (7 case) and suggestive malignancy (1 case), 25 cases (22.73%) were indeterminate follicular lesions, there were 87 cases (70%) of benign lesions comprising of nodular goiter [47 cases (42.73%)], hemorhagic cyst (24 cases), colloid cyst (5 case), thyroiditis (1 case). On postoperative histopathologic reports, there were 14 cases (12.73%) of malignant lesions comprising of papillary carcinoma [10 cases (9.09%)] and follicular thyroid carcinoma [4 case (3.64%)], there were 96 cases (87.26%) of benign lesions comprising of nodular goiter [44 cases (40%)], adenoma [32 cases (29.09%)], hemorhagic cyst (9 cases), colloid cyst (6 cases), multinodular (5 cases). After comparision of FNAB results with post thyroidectomy histopathologic results., the reliability and efficacy of FNAB were shown as accuracy 94.12%, specificity 100%, sensitivity 61.54%, false negative rate 38.46%, false positive rate 0%, predictive value for malignancy 100%, predictive value for benignancy 93.64%
Conclusions: Fine needle aspiration biopsy (FNAB) is a safe, simple, reliable and cost-effective means of detecting malignancy. FNAB, not thyroid scanning or ultrasonography, is the preferred initial diagnostic test in all patients with thyroid nodules. For many research reports FNAB 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. The reliability of present study is less efficacious than other reports, so we will study and develop every steps in the clinical assessment of patients with thyroid nodules at Surin Hospital.
Key words: Fine needle aspiration biopsy (FNAB), Thyroid nodules, Surin Hospital