Clinical correlates of false-negative fine needle aspirations of the breast in a consecutive series of 1,005 patients.

Fine needle aspiration (FNA) of the breast is a useful diagnostic tool in the management of lesions of the breast. However, false-negatives invariably occur and can detract from the usefulness of the technique. The current study of 16 patients with false-negative FNA of the breast from a consecutive series of 1,005 patients was undertaken in an attempt to better understand the clinical correlates most often associated with false-negative diagnoses. Pre-FNA physical examination and mammographic findings were correlated with the gross and microscopic features of these 16 patients. All 16 patients had palpable findings. Mammographic abnormalities were divided into three categories--highly suspicious for malignant tumor (n = 7), indeterminate (n = 3) and negative (n = 4). Mammograms were not available for two patients. The carcinomas ranged in size from 0.8 to 6.5 centimeters (mean of 1.9 centimeter). Thirteen of 16 carcinomas were 2 centimeters or less. Of the small tumors, histologic factors revealed no special type (NST) in six patients and special type carcinoma in seven patients. The notably large tumor (6.5 centimeters) was of high grade and demonstrated an unusual diffusely infiltrative pattern histologically extending between normal mammary lobules. Overall, special type carcinomas comprised seven of 16 patients. All of these carcinomas, as well as six of nine NST were paucicellular, that is, more than 20 percent area containing tumor cells. The current study supports the findings of others that small tumor size, paucicellularity and special type histologic factors contribute to false-negative diagnoses of FNA of the breast.