FNAC of thyroid nodule; diagnostic accuracy of fine needle aspiration cytology [FNAC]

ABSTRACT

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. If euthyroid, then fine needle biopsy provides direct specific information about the cytology of the nodule from which the histology can be inferred. To determine the accuracy of fine needle aspiration cytology [FNAC] in the diagnosis of solitary thyroid nodule and to avoid unnecessary surgery. This study was conducted in the Department of Surgery, Sheikh Zayed Medical College/ hospital Rahim Yar Khan. September 2008 to August 2009 [one year]. Fifty patients were included in the study. Prospective analytical study. The results obtained were compared with histopathology and efficacy of FNAC was checked by calculating sensitivity, specificity, positive predictive value and negative predictive value. Out of 50 cases, FNAC showed 43 cases as benign and 7 cases as malignant lesions, while histopathological examination revealed 42 benign and 8 malignant lesions. FNAC was able to correctly pick 41 benign lesions, while 2 cases of benign lesion turned out to be malignant on histopathology [False negative].Out of total 8 cases which turned out to be malignant on histopathology, FNAC was able to pick 6 cases, while one benign lesion was misdiagnosed as malignant [false positive]. The analysis of study showed a sensitivity of 75% and specificity 97.6% of FNAC in detecting malignancy in solitary thyroid nodule. This study concluded that FNAC is highly effective in detecting thyroid malignancy in solitary thyroid nodule with a sensitivity of 75% and specificity of 97.6%