[305] Terminal Duct Lobular Units(TDLU) in the Nipple: Implications for Nipple-Sparing Mastectomy (NSM)

Ji Yoon Yoon, Oleksandr N Kryvenko, Dhananjay Chitale, Min Woo Lee. Henry Ford Hospital, Detroit

Background: Breast cancer treatment has been greatly evolved from radical mastectomy to breast conserving therapy(BCT). As part of BCT and aesthetic approach, NSM is increasingly done for both cancer treatment and risk reduction, but has raised the oncologic safety issue since recurrence data on NSM is limited. Ductal & lobular neoplasia(DLN) is thought to arise in the TDLU. Therefore, our aim was to assess frequency of TDLU in grossly unremarkable nipples and its involvement by DLN. We also assessed involvement of lactiferous ducts in these nipples by DLN.
Design: We prospectively collected grossly unremarkable nipples from 66consecutive mastectomy specimens. Entire nipple was submitted. Nipples were transected at the base of nipple papilla: base-en face, papillae-vertically serially sectioned. Presence of TDLU & any epithelial proliferations were recorded.
Results: The indications for mastectomy were: 42invasive ductal carcinoma(IDC), 6ductal carcinoma in situ, 8invasive lobular carcinoma, 1lobular carcinoma in situ(LCIS), 9prophylactic. TDLU was seen in 17(25.8%) nipples; 6 at the en face base section, 6 in the perpendicular section of the papillae and 5 in both. Epithelial proliferations identified in TDLU were: 1 LCIS(case of IDC) and 1 columnar cell change(case of IDC).

No pathologic changes were found in nipples from prophylactic mastectomies. Occult ductal lesions without TDLU were: 3pagetoid extensions along lactiferous ducts(case of IDC), 1intraductal papilloma(case of IDC), 1direct extension by IDC, and 1dermal lymphatic involvement(case of IDC).
Conclusions: In our cohort, the frequency of TDLU was higher(25.8%) than previously reported two studies(9.4% & 17%) which would therefore make the development of a primary cancer in this area not unusual. We found TDLU in both at the base and papillae of nipple with equal frequency, unlike prior published study where TDLU were noted only near the base of nipple, with no TDLUs found at the tip. Occult nipple lesions which may be the source of recurrence / new malignancy were seen in 10.6%(7/66) of grossly uninvolved nipples. Our findings bring back the issue of oncologic safety when considering NSM and whether surgeons should routinely perform subcutaneous dissection under the areola that remove the maximum of glandular and ductal tissue.
Category: Breast

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 45, Monday Morning


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