Correlation of ultrasound, cytological, and histological features of 110 benign BI-RADS categories 4C and 5 nonpalpable breast lesions. The Institut Curie's experience.

BACKGROUND: The purpose of this study was to determine the pathological and ultrasound (US) features of benign nonpalpable breast lesions (NPBLs) classified as Breast Imaging Reporting and Data System (BI-RADS) category 4C or 5. METHODS: Between 2003 and 2007, 849 consecutive NPBLs detected at US and classified as BI-RADS category 4C (505) or 5 (344) initially underwent US-guided fine needle aspiration (FNA) at our institution. Benign diagnoses were established according to surgical excision findings or during a minimal 6-month imaging follow-up (mean, 3.7 years [SD, 2.6 years]). US BI-RADS features were reviewed and compared retrospectively using a chi-square test for the following pathological categories: epithelial and fibrous proliferation (EFP), cystic and papillary lesion (C&P), inflammatory lesion (IL), benign tumor (BT), intramammary lymph node (ILN), intraepithelial proliferative lesion (IPL), and nonspecific morphological alteration (NMA). The performance of FNA in the diagnosis of benignity was assessed. RESULTS: Of 849 NPBLs, 110 (12.9%) NPBLs were benign: 88 (17.4%) were BI-RADS category 4C, and 22 (6.4%) were BI-RADS category 5. Forty-four (40%) were EFPs, 21 (19%) were C&Ps, 13 (12%) were NMAs, 11 (10%) were ILs, 11 (10%) were BTs, 8 (7%) were IPLs, and 2 (2%) were ILNs. Lesion shape, US pattern distribution, and posterior features showed statistically significant differences between these categories (P < .05): 33 (75%) EFPs exhibited posterior shadowing, 18 (86%) C&Ps were homogenous, 9 (82%) ILs were heterogeneous, 11 (100%) BTs were homogeneous, 9 (82%) BTs were oval, and 6 (75%) IPLs were irregularly shaped. Of the 110 benign NPBLs, FNA diagnosis was falsely positive in 7 (6%), suspicious in 10 (9%), and benign in 90 (82%), and 3 (3%) were inadequate for diagnosis. CONCLUSION: A diverse array of benign NPBLs can be classified as BI-RADS category 4C or 5 on US, each showing specific imaging presentations.

Diagnostic Performance of Ultrasound-Guided Fine-Needle Aspiration of Nonpalpable Breast Lesions in a Multidisciplinary Setting: The Institut Curie's Experience.

OBJECTIVES: To assess the diagnostic performance of ultrasound-guided fine-needle aspiration (USFNA) in nonpalpable breast lesions (NPBLs) in a multidisciplinary setting. METHODS: In total, 2,601 NPBLs underwent USFNA by a radiologist-pathologist team. Gold-standard diagnosis was based on surgery, core-needle biopsy, or 1-year imaging follow-up. USFNA's diagnostic performance was analyzed in different clinical and imaging subgroups. RESULTS: USFNA's sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were, respectively, 92.6% (95% confidence interval [CI], 90.8%-94.2%), 96.8% (95% CI, 95.8%-97.6%), 94.8% (95% CI, 93.2%-96.1%), and 95.4% (95% CI, 94.3%-96.4%). The best PPV was achieved in Breast-Imaging Reporting and Data System (BI-RADS) categories 4C and 5 and the best NPV in BI-RADS categories 2, 3, and 4A and in patients younger than 50 years. The mitotic count, BI-RADS categories, associated palpable cancer, and age (<50 or ≥50 years) were statistically independent factors ( P < .05) between USFNA's false-negative and true-positive results. CONCLUSIONS: USFNA is a robust diagnostic procedure in NPBLs. Age and the BI-RADS category of the lesion are important factors determining its performance.