Value of fine needle aspiration cytology in diagnosis of thyroid nodules at Kenyatta National Hospital

Abstract

Thyroid nodules are common at Kenyatta National Hospital. About five new cases are seen weekly. The results of 398 consecutive Fine Needle Aspiration Cytology (FNAC) of thyroid from 383 patients performed and interpreted by different pathologists between 1st January and so" June 1997 were retrospectively reviewed and compared with their histologic findings. The objective of the study was to assess the value of FNAC in the diagnosis of thyroid nodules with emphasis on consistency and accuracy using histology as the "Gold Standard". The study population consisted of 347 (90.6%) females and 36 (9.40/0) males. The age of the study population ranged from 15 - 78 years. A total of 318 (87.10/0) FNAC had sufficient material for Cytologic diagnosis. Of these 249 (78.3%) were benign hyperplastic lesions. Only seven (1.83%) of the population studied were diagnosed as cancers. Surgical confirmation of the Cytologic diagnosis was obtained in 75 of the cases, of which 60 (80%) were accurately called benign or malignant. A further 9 (150/0) cases who had unsatisfactory FNAC were found to be benign. In 48 (64.00%) of the cases the cytologic diagnosis was consistent with the histologic diagnosis. The calculated sensitivity was 80%, specificity 1000/0, accuracy 98.60/0, positive and negative predictive values were 100% and 98.8% respectively. There was one false negative and no false positives. The study shows that FNAC is a sensitive, specific, accurate and cost effective technique in the management of patients with thyroid nodules. It should be used along with clinical assessment as the first diagnostic technique to determine the management of thyroid nodules at K.N .H.. This would assist in selecting patients for surgery and a reduction in cost of management of patients with thyroid nodules.