Critical clinicopathologic analysis of 23 cases of fine‐needle breast sampling initially recorded as false‐positive

BACKGROUND Because false‐positive cytologic diagnoses in breast tumors are rare, few cases have been reported, although their consequences may be highly detrimental to the patient. The authors report the Institut Curie's experience, by using a multidisciplinary approach. METHODS Of 9334 benign breast tumors examined preoperatively for cytologic diagnosis by fine‐needle sampling (FNS), the 23 (0.25%) FNS cases considered to be false‐positive were retrospectively reviewed and analyzed. RESULTS Tumors were situated close to the nipple in 7 cases and away from the nipple in 16 cases. Tumor stage was T0 for 1 case, T1 for 18 cases, and T2 for 4 cases. Radiologically, six tumors were classified as malignant, seven as indeterminate or suspicious, and nine as benign. Three of six tumors studied by flow cytometry were DNA aneuploid. Based on a multidisciplinary clinicopathologic review, 20 FNS cases were finally classified as false‐positive, and the remaining 3 tumors with malignant FNS and subsequent benign histology were classified as true‐positive, because local and/or metastatic progression was observed in the short term. CONCLUSIONS The authors' review suggests two categories of false‐positive cases: the first in which cytologic benign patterns are overdiagnosed, and the second in which atypical morphologic criteria were present. Nevertheless, as shown by the malignant course in three cases, patients with malignant preoperative FNS and corresponding benign histology always require close clinical follow‐up. Finally, surgical overtreatment rate could be decreased if all radiologically benign tumors with positive/suspicious FNS were subject to intraoperative frozen section examination. Cancer (Cancer Cytopathol) 2001;93:132–139. © 2001 American Cancer Society.