Sub-classification of Breast Masses by Fine Needle Aspiration Cytology.

OBJECTIVE: The aim of this study is to evaluate the accuracy of sub-classification of breast diseases using Fine Needle Aspiration cytology (FNAC).

MATERIALS AND METHODS: A one-year prospective study of 180 consecutive patients with palpable breast lesions who underwent FNAC and subsequently open surgical biopsy for histological confirmation. FNAC was used to sub-classify breast lesions and then correlated with histological diagnosis.

RESULTS: A total of 180 patients were enrolled into the study but only 110 patients with histology report were used for test validity. Seventeen (15.5%) smears were C1; while 46 (41.8%), 5 (4.5%), 4 (3.6%) and 38 (34.6%) were C2, C3, C4 and C5, respectively. FNAC achieved sensitivity of 90.0%, specificity of 95.5%, false positive rate of 5.3%, false negative rate of 8.7%, positive predictive value of 94.7%, negative predictive value of 91.3% and overall diagnostic accuracy of 92.9%. Only 86 (78.2%) of the 110 smears could be sub-classified into different disease conditions of the breast on cytology. FNAC accurately sub-classified 25(78.1%) of fibroadenoma and 28(87.5%) of invasive ductal carcinoma.

CONCLUSION: FNAC can reasonably sub-classify fibroadenoma, invasive ductal carcinoma and mastitis but there is still a challenge with lobular carcinomas, metaplastic carcinomas, papillary carcinomas and fibrocystic changes.