A comparative study of fine needle aspiration cytology versus non aspiration technique in thyroid lesions

Abstract

Background: Fine needle aspiration cytology (FNAC) is regarded as the gold standard investigation in the diagnosis of thyroid swellings. But often unsatisfactory specimen, especially mixed with blood, poses an obstacle in proper cytological interpretation. To overcome this problem, an alternative method of fine needle non aspiration cytology (FNNAC) technique was developed which, relies on the capillary pressure only to suck the cells inside the needle bore.Methods: Patients presenting with thyroid swellings from July 2008 to January 2009 were included in the study. 91 patients treated for thyroid lesions entered a prospective comparative evaluation of fine needle cytology with aspiration and non-aspiration techniques in thyroid. The thyroid swelling in every patient was sampled by both the aspiration as well as the non-aspiration technique by a single operator. Both procedures were done using 23G needles. Aspiration was done using a 10ml syringe. Both dry and wet smears were made and stained. All smears were interpreted by a cytologist without knowledge of the technique employed. Apart from the diagnosis, comments were made on the quality of the slides and three qualitative categories are created as unsuitable specimens, diagnostically adequate and diagnostically superior.Results: Non-neoplastic lesions accounted for 92.3%. They comprised mainly of nodular colloid goiter 53.84%, colloid nodules 29.6%, thyroiditis 8.79%, and one case of suppurative lesion. Out of the 7 neoplasms, 2 were follicular neoplasms, 1 was papillary carcinoma, 2 cases of Hurthle cell neoplasm and 1 cellular nodule in an MNG. Diagnostically superior material was obtained in 42 cases (46.15%) of the non-aspiration samples, as compared with 18 cases (19.78%) of aspiration samples which was statistically significant.Conclusions: The FNNAC produces better results in the form of a better quality of the cellularity and less field obscurity by blood. This technique should be used alone or in tandem with FNAC for better diagnostic yield.