[316] Clinical Analysis of Mucocele-Like Tumors of the Breast: Analysis of a Large Benign Breast Disease Cohort

DW Visscher, R Vierkant, M Frost, C Reynolds, S Anderson, L Hartmann. University of Michigan, Ann Arbor, MI; Mayo Clinic, Rochester, MN

Background: Mucocele-like tumors (MLT) of the breast are unusual lesions characterized by cysts distended with mucin that also dissects/extravasates through the epithelium into surrounding stroma. They are accompanied by variable epithelial proliferation, with an increased frequency of associated atypical ductal hyperplasia (ADH). It is not known whether MLT represent a risk factor for subsequent development of breast carcinoma.
Design: Our benign breast disease cohort is comprised of 9376 women who underwent excisional breast biopsy from 1967-1991. Slides from all patients were reviewed retrospectively in a blinded fashion and classified per standard diagnostic criteria by two study pathologists. Mean follow up is 13.7years. We analyzed subjects with MLT diagnoses for the frequency of proliferative lesions, including ALH/ADH, and for their likelihood of developing breast cancer.
Results: The cohort contained 70 MLT (0.75%). Thirty patients (42.9%) were >55yrs of age at time of diagnosis, 24 (34.3%) were 45-54yrs and 16 (22.9%) were <45yrs. MLT were more often associated with proliferative lesions (70% in MLT vs 33% for the cohort overall). ALH/ADH was present in 21.4% MLT lesions, vs 3.4% in the cohort overall (p<0.0001). To date, 6/70 patients with MLT (8.6%) have developed breast carcinoma; this frequency is not significantly different than the BBD cohort overall (p=0.8780).
Conclusions: Our findings support previous studies showing a relationship between MLT and atypia. However, beyond the risk associated with atypia itself, we do not observe an additional risk of breast carcinoma associated with the presence of the MLT.
Category: Breast

Tuesday, March 10, 2009 1:00 PM

Poster Session IV # 25, Tuesday Afternoon