No elevation in long-term breast carcinoma risk for women with fibroadenomas that contain atypical hyperplasia

BACKGROUND. The authors previously showed that women with a fibroadenoma ha ve a relative risk of invasive breast carcinoma of approximately 2.0 compar ed with women of similar age from the general population. This relative ris k approaches 1.0 when family history and proliferative changes in the adjac ent parenchyma are removed and rises to > 3.0 if the fibroadenoma has compl ex histology. The risk for developing breast carcinoma in women with atypic al lobular hyperplasia (ALH) and atypical ductal hyperplasia (ADH) or their minimal variants within a fibroadenoma is unknown. METHODS. The authors conducted a long-term, retrospective cohort study of 1 834 women with adequate follow-up who presented with fibroadenoma at three local hospitals between 1950 and 1968. Histology was reviewed using establi shed criteria, and the patients were categorized with ALH, ADH, minimal aty pia, or no atypia. RESULTS. The overall prevalence of ALH or ADH within fibroadenomas was 0.81 %. Minimal or true atypia within a fibroadenoma appeared to be correlated w ith proliferative disease in the adjacent parenchyma but could not predict for the presence there of well-established atypia. Only 7% of women with we ll-developed atypia developed invasive carcinoma on follow-up. Three women with minimal atypia developed invasive carcinoma. CONCLUSIONS. In this study of a large cohort of women with fibroadenoma, th e authors found that atypia within a fibroadenoma cannot predict for the pr esence of atypia within adjacent breast parenchyma. They also found that at ypia confined to a fibroadenoma does not incur a clinically meaningful risk of future breast carcinoma development greater than that of fibroadenoma a lone. Cancer 2001;92: 30-6. (C) 2001 American Cancer Society.