The Definitive Microscopic Characterization and Long Term Follow Up of Patients with Collagenous Spherulosis. A Benign Breast Disease Cohort Study
Mark D Laudenschlager, Daniel W Visscher, Robert Vierkant, Marlene Frost. Mayo Clinic, Rochester, MN
Background: Relegated into the realm of histologic distraction, the delicate eosinophilic spider-like strands and radial deposits of collagenous spherulosis (CS) have not been linked to risk of developing a breast malignancy. Yet, given their propensity to proliferate and calcify, CS foci are detected by mammography, subsequently biopsied and observed microscopically. A prior study reported an associated premalignant or malignant process in over half of their cases of CS (56% - 33 of 59). This prompted speculation that perhaps CS should be included in the category of proliferative breast disease with atypia. Such a hypothesis had not previously been tested with a benign breast disease cohort. Furthermore, we sought to examine the microenvironment of CS in order to identify common attributes and definitively characterize this entity. This is the largest series of CS cases to be reviewed and the only one with long term follow-up.
Design: We identified 68 CS cases from a benign breast disease cohort of 9,087 women. This population is comprised of an institutional review board approved study of women (ages 18 – 85), who underwent benign breast biopsies during 1967 to 1991. Our intent was to ascertain how many women with CS went on to develop mammary carcinoma. Risk of subsequent breast cancer by CS and other covariates was assessed via standardized incidence ratios (SIR), using the Iowa SEER registry as the reference population.
Results: Within our study, 11% (8 of 68) of the women with CS went on to develop DCIS or invasive mammary carcinoma. Tumor was contralateral in 2 cases. The interval between benign biopsy and subsequent malignancy ranged from 6 to 31 years, with a mean of 19 years. Atypical ductal hyperplasia or atypical lobular hyperplasia was identified on the initial biopsy in 5 of the 68 cases. Yet, none of these women went on to develop mammary carcinoma. In the end, women with CS did not demonstrate a statistically significant elevated risk of breast cancer (SIR 1.64%, 95% CI 0.71 – 3.23).
Conclusions: Our findings show the presence of CS within a benign breast tissue biopsy does not with any statistical significance increase a woman's risk for later development of mammary carcinoma. However, given the consistently observed presence of columnar altered lobules, micropapillomas, and surrounding dense stromal fibrosis within the microenvironment of CS; it appears as though CS is a manifestation of an evolving columnar cell lesion.
Monday, March 4, 2013 1:00 PM
Poster Session II # 51, Monday Afternoon