False-positive and false-negative cases of fine-needle aspiration cytology for palpable breast lesions.

BACKGROUND: Fine-needle aspiration cytology (FNA) is less traumatic and technically easy to apply to small breast tumors. METHODS: A total of 382 cases of palpable breast lesions that had undergone fine needle aspiration and histopathologic diagnosis were reviewed with an emphasis on the rate of false positive diagnoses in benign breast lesions. RESULTS: A diagnosis of " malignant " was made in 98 of the 382 specimens (25.6%). The predictive value for malignancy was 97.9%. The sensitivity, specificity, and accuracy of FNA were 86.3%, 98.2%, and 93.2%, respectively, when the " suspicious " group was considered positive for malignancy. The histologic subtypes of the 4 false-positive cases were epithelial proliferative lesions, ductal or lobular hyperplasia. None of these 4 cases were definitely diagnosed as " malignant " by radiological studies. Four false-negative cases by FNA were suspicious for malignancy radiologically. There was no specific pathological subtype associated with false-negative status on FNA in this study. CONCLUSION: Palpable breast tumors can be definitively diagnosed based on a combination of physical examination, radiological studies and FNA, when the radiological studies concur with the diagnosis by FNA.