Fine needle aspiration cytology as the primary diagnostic tool in thyroid enlargement

In the preoperative decision-making of the thyroid swellings, fine needle aspiration cytology (FNAC) is becoming an ever more vital tool.

To compare the advantage of preoperative FNAC of thyroid swellings with postoperative histopathology to reach a consensus protocol as a simple procedure for diagnosis and optimal management of thyroid swellings.

A prospective study of preoperative FNAC was carried out on 178 incidental thyroid swellings attending a tertiary care centre in Kishanganj, Bihar. Evidence-based surgical interventions were done, irrespective of FNAC findings and diagnosis was confirmed by histopathological examination (HPE) postoperatively in all the cases.

In the FNAC, preponderance of the cases (75.84%) was colloid goitre followed by granulomatous thyroiditis; follicular carcinoma was noted in 7.30 percent and anaplastic carcinoma in 3.37 percent of cases. Histopathological examination showed colloid goitre predominantly (76.97%), followed by follicular carcinoma (8.99%). The overall prevalence of malignancy was 11.24 percent diagnosed by HPE and 9.55 percent by FNAC. In our FNAC series sensitivity of was 90 percent while specificity was 100 percent; accuracy was 98.88 percent. Predictive value of a positive test and negative tests was 100 percent and 98.75 percent respectively.

The study highlights that FNAC should be treated as a first-line diagnostic test for thyroid swellings to guide the management though this is not a substitute for HPE as a need to improve primary healthcare in India.