Abstract
Abstract
Background
Atypical ductal hyperplasia (ADH) refers to an intraductal clonal epithelial proliferation (≤2 spaces or ≤2 mm). On core needle biopsies (CNBs), ADH is associated with surgical upgrade rates ranging from 0% to 62%. Poor interobserver reproducibility for ADH vs usual ductal hyperplasia (UDH) and low-grade ductal carcinoma in situ (LG-DCIS) may in part explain variable upgrade rates. Immunohistochemistry with CK5/6 and ER is useful for distinguishing the polyclonal UDH from clonal ADH and LG-DCIS. Ductal intraepithelial neoplasia (DIN) has been suggested as alternative terminology for clonal intraductal proliferations: DIN1 (ADH and LG-DCIS), DIN2 (IG-DCIS), and DIN3 (HG-DCIS).
Design
The primary objective was to determine the upgrade rate for a diagnosis of ADH based on CK5/6 and ER and size ≤2 mm on CNBs obtained from 2014 to 2017. The secondary objective was to study the impact that use of DIN1 for ADH and LG-DCIS would have on upgrade rate. Upgrade rate for ADH was determined using the subsequent excision diagnoses: negative for residual disease (NEG), ADH, DCIS, and invasive ductal carcinoma (IDC). Upgrade rate was then recalculated replacing DIN1 for ADH on CNB and comparing against the excision diagnosis of NEG, DIN1, DIN2, DIN3, and IDC.
Results
Thirty-five patients had image-guided, vacuum-assisted CNB for BI-RADS 4 or 5 target lesions (calcifications/mass densities) using 9g(23), 12g(10), or 14g(2) needles, followed by surgical excision for ADH. There was a diagnostic upgrade of 34% (9 LG-DCIS, 2 IG-DCIS, 1 IDC). Size of upgraded lesions ranged from 3 mm to 8 mm. When ADH and LG-DCIS were termed DIN1, the upgrade rate decreased to 8.6%.
Conclusion
Strict criteria for the diagnosis of ADH on CNB, as well as terminology like DIN that addresses a clonal relationship to LG-DCIS, decrease rates of surgical upgrade. Unification of terms and removal of the “malignant” connotation for these small, low-grade intraductal clonal proliferations is timely.
