Fat necrosis of the breast simulating recurrent carcinoma after primary radiotherapy in the management of early stage breast carcinoma.

Between March 1973 and December 1980, 76 patients with Stage I or II breast carcinoma were treated by biopsy and definitive radiation therapy at Stanford University Medical Center. There were 78 treated breasts since two patients had bilateral carcinomas at presentation. During a median follow-up period of 29 months, eight patients developed discrete masses in the treated breast. In four of these patients biopsied tissue revealed recurrent carcinoma yielding a local control rate of 95%. Four additional patients had lesions which were clinically indistinguishable from recurrent cancer. Biopsy specimens, however, revealed fat necrosis of the breast. The clinical and pathologic features of this entity are described. It is imperative that clinicians be aware of this treatment sequelae so that conservative diagnostic procedures may be used and breast deformity minimized. If postirradiation fat necrosis is considered, mastectomy for suspected persistent or recurrent disease may be avoided.