[331] Routine Histologic Parameters Can Predict the Presence of Breast Carcinoma Following a Core Biopsy Showing Atypical Ductal Hyperplasia: A Clinicopathologic Study of 124 Cases

C Zhang, YE Wang, F Liu, MM Steinhoff, MR Quddus, J Kasznica, CJ Sung. Women & Infants Hospital of Rhode Island, Warren Alpert Medical School of Brown University, Providence, RI

Background: In this study, we arbitrarily divided atypical ductal hyperplasia of the breast (ADH) into two subtypes, types I and II, diagnosed in the following manner: i) in type I ADH, duct is completely replaced by cells of low-grade carcinoma in-situ but the lesion is smaller than 2 mm, and ii) in type II ADH, ducts were partially involved by DCIS-like cells regardless of the lesional size. The diagnosis of ADH in a core biopsy (CoBx) often leads to an excisional biopsy (ExBx) to exclude carcinoma. Our aim was to derive practical histopathologic parameters, using routine H&E stains, to determine whether histologic subtyping of ADH can predict the presence of carcinoma in the breast.
Design: We retrieved from our institutional pathology archives all cases of ADH diagnosed by CoBx and followed by ExBx during the period from January 1, 2001 to December 31, 2005. CoBx cases were reviewed to confirm the diagnosis and to categorize the lesions into either type I or type II ADH as defined above. The presence of carcinoma, either carcinoma in-situ (DCIS) or invasive carcinoma, in the ExBx specimens was correlated with each type of ADH noted in the prior CoBx. Fisher Exact Test was used to compare the frequencies of carcinoma in the ExBx specimens that were associated with either type I or II ADH.
Results: Of a total of 131 cases, the original CoBx diagnosis of ADH was confirmed in 124 cases. 41 of 124 cases (33.1%) showed either DCIS, invasive ducatal carcinoma (IDC), or both DCIS and IDC in the subsequent ExBx specimens (these were referred to positive ExBx specimens). 33 of 124 CoBx cases (26.6%) fell into our type I ADH, and 91 of 124 CoBx cases (73.4%) into our type II ADH. Positive ExBx specimens followed type I ADH in 26 of 33 cases (78.8%) and followed type II ADH in 15 of 91 cases (16.5%) (p< 0.001). Within the 26 positive cases in type I ADH, 21 showed DCIS alone, 2 IDC alone, and 3 DCIS and IDC. Among the 15 positive cases of type II ADH, 13 exhibited DCIS alone, and 2 DCIS and IDC.
Conclusions: Our so-called type I ADH seen in CoBx is more frequently associated with carcinoma (either in-situ or invasive) in the ExBx specimens than type II ADH. Specifying the histologic subtype of ADH in the pathology report of a core biopsy may prove useful in predicting the presence of carcinoma in the breast.
Category: Breast

Monday, March 9, 2009 8:30 AM

Platform Session: Section B, Monday Morning