Fine needle aspiration cytology of thyroid swellings: how useful and accurate is it?

BACKGROUND: Fine needle aspiration cytology (FNAC) is widely considered as the diagnostic technique of choice in the assessment of thyroid lesions. AIMS: The aim of this study is to determine the utility and diagnostic accuracy of FNAC of thyroid lesions performed at our institution and to compare our experience with that of the experts from other regions of the world. SETTING AND DESIGN: The present study is a five-year retrospective study of FNAC of thyroid lesions performed in the Pathology Department of our institute, during the period January 2004 to December 2008. The FNAC findings were correlated with the histopathological diagnosis, wherever available. MATERIALS AND METHODS: The records of 252 patients who had undergone FNAC during the study period were retrieved and information about age, sex, FNAC, and Histopathological diagnoses were extracted and the corresponding original slides were reviewed. The cytological results were classified as inadequate, benign, suspicious, and malignant. The histopathology diagnosis was classified as non-neoplastic (benign) and neoplastic (malignant). RESULTS: A total of 252 FNACs of thyroid lesions were done during the study period. The results of the FNA cytological diagnosis showed that four (1.6%) of the patients had FNAs, which were inadequate for cytological assessment, 228 (90.5%) patients had benign lesions, 17 (6.7%) had lesions that were suspicious for malignancy, and three (1.2%) had malignant neoplasms. The correlation of the FNAC findings with the histopathological diagnosis, showed that our FNAC diagnostic accuracy rate was 96.2%, with a sensitivity of 66%, and specificity of 100%. CONCLUSIONS: The results of our study are comparable with the current published data and demonstrate that FNA cytology is a sensitive, specific and accurate initial diagnostic test for the preoperative evaluation of patients with thyroid swellings in our setting as well. The clinicians should be encouraged to embrace this procedure in the initial management of such patients.

The influence of refractoriness to adenosine 5'-monophosphate on allergen-provoked bronchoconstriction in asthma.

Repeated bronchoprovocation with adenosine 5'-monophosphate (AMP) in atopic, nonasthmatic subjects produces a state of refractoriness to the nucleotide that may be due either to depletion of preformed mediators from airway mast cells or down-regulation of purinoceptors on the surface of these cells. To investigate this further, we compared the effect on immediate allergen-provoked bronchoconstriction of preceding repeated challenges with histamine and AMP in eight atopic, mildly asthmatic subjects. In three successive AMP concentration-response studies, the geometric mean PC20 AMP increased from 275.3 to 1154.3 (p less than 0.01) and 1976.7 (p less than 0.01) mg/ml, respectively, whereas no significant similar increase in PC20 occurred with repeated histamine challenges. Refractoriness to AMP was not associated with any significant decrease in airways responsiveness to histamine. When compared with the response after repeated provocation with inhaled histamine, repeated exposure of the airways to AMP potentiated, rather than inhibited, immediate allergen-induced bronchoconstriction by a mean 57 +/- 22.6% (p less than 0.05) when the data were expressed as the area under the FEV1-time response curve. The ability of airways that have been rendered less responsive to inhaled AMP to exhibit an increased response to allergen suggests that tachyphylaxis to AMP is unlikely to be caused by depletion of preformed mast cell-derived mediators such as histamine.