Characterization and outcome of breast needle core biopsy diagnoses of lesions of uncertain malignant potential (B3) in abnormalities detected by mammographic screening

Abstract

In the setting of breast cancer screening, 5-9% of needle core biopsies are diagnosed as lesions of uncertain malignant potential (B3). The management of these lesions is potentially problematic as the data on their outcome remains limited. In our study, we aim to assess the outcome of screen-detected lesions diagnosed as B3 in a large series to validate previous studies and to characterize the malignant lesions detected after a B3 diagnosis. Therefore, the results of 1,025 needle core biopsies of women screened over a 7-year period (1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006) in two different regions in the UK with B3 diagnoses who underwent surgical excision were reviewed and compared to the final excision histology. Final histology showed that 25% of cases were malignant (17% ductal carcinoma in situ and 8% invasive). Predictors of malignancy included calcification on imaging and epithelial atypia on needle core biopsy particularly atypical ductal hyperplasia [positive predictive value 50%]. Pure flat epithelial atypia showed the lowest positive predictive value amongst all epithelial atypia groups (21%). The positive predictive value was low for complex sclerosing lesions (9%) and papillary lesions (13%) without epithelial atypia. Malignant tumors detected after B3 diagnosis showed favorable histological features, the majority were in situ, and most belonged to the low grade breast neoplasia family that is associated with indolent behavior. The underlying radiological abnormality was calcification in 44% of cases and the imaging classification was malignant/suspicious in 38%. In conclusion, our results further emphasize the heterogeneity of B3 lesions and that the likelihood of malignancy varies substantially between different histological subtypes. Malignancy is particularly associated with epithelial atypia suggesting the use of two categories of with and without epithelial atypia. Radiological findings provided useful information regarding the nature and outcome of B3 lesions.

Non-Malignant Breast Papillary Lesions - B3 Diagnosed on Ultrasound - Guided 14-Gauge Needle Core Biopsy: Analysis of 114 Cases from a Single Institution and Review of the Literature

“…Seven studies [7,22,36,38,39,42,44] are comparable to our study considering the homogeneity of series reported (US 14G NCB). These studies report a range of underestimation rate between 15 and 47 %, and our value of underestimation rate (47.8 %) results to be very close to superior limit of this range.…”

“…These studies report a range of underestimation rate between 4 and 12.9 %, and our value of underestimation rate (13.2 %) results to be very close to superior limit of this range. The five larger series [7,36,38,39,42] using 14G NCB reporting more than one-hundred cases (160, 131, 155, 203 and 191) show a wide range of underestimation rate (5, 9, 12.9, 6 and 5 % respectively).…”

Rates of Presurgical Underestimation of Breast Cancer after Standardized Assessment of Breast Calcifications

“…Similarly to previous results, we found AEPDT to be the B3 lesion with the highest rate of finally detected malignancy (40 % [7], 50 % [10]). 30.4 % (7/23) of the diagnoses of AEPDT in minimally invasive biopsy were not proved as atypical ductal hyperplasia (ADH) after excision surgery but were upgraded to a malignant diagnosis, mainly to DCIS diagnosis (85.7 %).…”

The low nuclear grade breast neoplasia family

“…ADH is recognized both as a risk indicator and a non-obligate precursor of low-grade DCIS and invasive BC though the risk of development of invasive carcinoma is smaller than that observed with DCIS. 23 Unlike low-grade DCIS, high-grade DCIS is not a part of LGBNF. When high-grade DCIS progresses to or presents with invasive cancer, the latter is usually of high-grade and they share the same pattern of genetic aberrations.…”