IN SEARCH OF SPECIMEN ADEQUACY IN FINE-NEEDLE ASPIRATES OF NONPALPABLE BREAST-LESIONS

Pathology-related medical malpractice claims frequently concern fine-n eedle aspirations (FNAs) of breast lesions, and diagnostic errors have been attributed in part to the inadequacy of the specimens. Cytologic criteria for adequate FNA specimens, specifically in cases without ma lignancy, have not been clearly defined. From January 1988, to August 1995, 669 ultrasonographic-guided FNAs of nonpalpable, solid breast le sions with subsequent histologic examination were performed at our ins titution. From these, 54 cases with cytologic diagnoses of insufficien t or nonspecific benign findings were identified. All aspirates were r eviewed, and the number and size of the epithelial cell groups were qu antitated in each case. By using criteria for adequate aspirates of pa lpable breast lesions (six or more epithelial cell groups per case wit h a minimum of 5-10 cells per group), 23 of the 54 aspirates were deem ed inadequate and 31 adequate. Eleven (48%) of the inadequate aspirate s and 17 (55%) of the adequate aspirates were from histologically conf irmed carcinomas (ductal carcinoma in situ, 6; invasive carcinoma, 22, of which 12 were ductal, 7, lobular, and 3, mixed ductal and lobular) . For the mammographic diagnoses ''probably benign,'' ''indeterminate, '' and ''suggestive of malignancy or malignant,'' the probability of m alignancy in aspirates of adequate cellularity leg, > 6 epithelial gro ups) was 9%, 40%, and 93%, respectively. These findings indicate that a significant proportion of breast aspirates still may yield false-neg ative results despite adequate to high cellularity Although a definiti on of adequacy based on cellularity is useful in reducing false-negati ve results, cellularity alone cannot be relied on in the management of nonpalpable lesions. For mammographic findings that are indeterminate or suggestive of malignancy or malignant, nonspecific FNA findings sh ould be followed by core or excisional biopsy to exclude carcinoma.