Fibrous tumor of the breast in a postmenopausal woman receiving estrogen.

Fibrous tumor of the breast is a rare, benign stromal proliferation with atrophy of the epithelial component. Almost all patients who develop fibrous tumors are premenopausal. An unusual example of fibrous tumor of the breast is reported in a 62-year-old postmenopausal woman. The mass, first noted 1 year previously, progressively enlarged over the year. The patient noted a history of taking exogenous estrogens for 10 years. Intense estrogen administration during the year of enlargement may be associated with accelerated growth of the tumor. In addition, positive nuclear staining for estrogen receptor antibodies in stromal cells was demonstrated by immunohistochemical methods.