Computer-assisted complete three-dimensional reconstruction of the mammaryductal/lobular systems - Implications of ductal anastomoses for breast-conserving surgery

BACKGROUND. The intraductal spread of breast carcinoma can occur along the mammary ductal/lobular systems (MDLS) with no invasion of tissues. Because ductal anastomoses in the MDLS are considered to be a possible risk factor for extensive intraductal spread of breast carcinoma, the architecture of t he MDLS has important therapeutic implications for patients treated with br east-conserving surgery. METHODS. An entire breast resected by subcutaneous mastectomy from a 69-yea r-old woman with ductal carcinoma in situ (DCIS) was examined in submacrosc opic sections by stereomicroscopic and histologic techniques. Serial 2-mm s ections underwent computer-assisted complete three-dimensional reconstructi on of all MDLS. RESULTS. The entire breast that was studied contained 16 MDLS that were arr anged radially, with the nipple at the center. Of these 16 MDLS, 4 (25.0%) had ductal anastomoses whereas the remaining 12 MDLS had no ductal anastomo ses and completely independent regional anatomy. Ductal anastomoses were ob served at 11 sites in the 4 MDLS. The 2 of 11 ductal anastomoses that conne cted different MDLS (18.2%) were situated > 4 cm from the nipple. The remai ning nine ductal anastomoses connected ducts within the same MDLS; their lo cation varied from near the nipple to the peripheral region. In the specime n examined, DCIS extended only within a single MDLS and did not spread betw een different MDLS via ductal anastomoses. CONCLUSIONS, To the authors' knowledge, the current study is the first time the complete architecture of all MDLS in an entire breast has been studied three-dimensionally. The risk of promoting the intraductal spread of disea se during surgery may be greater when intraductal lesions extend more perip herally than centrally. The features of ductal anastomoses may provide a si gnificant anatomic clue regarding negative surgical margins in breast-conse rving surgery. (C) 2001 American Cancer Society.