Occurrence of breast carcinoma within a fibroadenoma. A review.

Sixty-two cases of carcinoma within a breast fibroadenoma are adequately documented in the literature, including the present case. All are found in women. The mean age of occurrence is 42.4 years. This corresponds to the peak age of lobular in situ breast cancer but is much higher than the peak age for breast fibroadenomas. Sixty-five percent of patients harboring cancer within a fibroadenoma have lobular in situ malignant neoplasms. In 42% of the cases the surrounding breast tissue is also involved by cancer, a fact that dictates generous surgical margination of all fibroadenomas excised, especially in older women. The data indicate that the presence of the fibroadenoma is a parameter independent of the development of cancer in either the ipsilateral or contralateral breast and does not influence the clinical course of the malignant neoplasm, other than that it contributes to its earlier detection. Treatment should follow the general principles of therapy for the in situ or infiltrative breast cancers.