[262] Background Microenvironmental Changes in Atypical Hyperplasia of the Breast
John K Schoolmeester, Lynn C Hartmann, Marlene H Frost, Daniel W Visscher. Mayo Clinic, Rochester, MN
Background: Benign breast disease (BBD), encompassing nonproliferative changes, proliferative disease without atypia, and atypical hyperplasia (AH), has been proven an important risk factor for subsequent development of breast cancer. The comprehensive identification of these background microenvironmental changes in AH and whether they collectively represent a precursor state, contribute to or create the conditions necessary for development of epithelial atypia has not been previously studied.
Design: Background microenvironmental changes were assessed in 47 randomly selected biopsies with AH (25 atypical lobular hyperplasia, 22 atypical ductal hyperplasia) from women enrolled in our BBD cohort. This cohort consists of 9087 women, aged 18-85, who had a benign breast biopsy between 1967-1991. Each biopsy was evaluated for nonproliferative changes, proliferative disease without atypia, AH, and the presence of calcifications in benign or atypical ducts in a single slide.
Results:
| Background Microenvironmental Changes | ALH, n=25 | ADH, n=22 |
| Nonproliferative Changes | 22 | 17 |
| Columnar Cell Lesions | 20 (7 CC, 9 CH, 4 FEA) | 19 (2 CC, 6 CH, 11 FEA) |
| Sclerosing Adenosis | 11 | 11 |
| Moderate-Florid Usual Ductal Hyperplasia | 6 | 5 |
| Radial Scar and/or Papilloma | 5 | 10 |
| Two Proliferative Lesions | 11 | 13 |
| Three Proliferative Lesions | 1 | 1 |
| Greater than Three Proliferative Lesions | 2 | 3 |
| Calcifications Associated with Benign Ducts | 9 | 8 |
| Calcifications Associated with Atypical Ducts | 6 | 11 |