Nine cases of benign breast disease in which mammograms had been false-positive were collected at Northwestern Memorial Hospital. In all but one case the patients had presented initially with questionable masses that required biopsies with requests for frozen section diagnoses. Included in the study were three cases of indurative mastopathy, three cases of fibrocystic disease with sclerosing adenosis, and one case each of sclerosing papillary proliferation, infarcted intraductal papilloma, and fat necrosis with foreign body giant cell reaction. The mammographic and histologic findings for all cases were reviewed. Indurative mastopathy is a poorly known entity with radiologic features highly suggestive of malignancy. As described previously (Cancer 47:561, 1981), the lesion consists of a central nidus of elastosis with irregular projections radiating into the adjacent breast tissue. Peripheral areas of the infarcted papilloma and sclerosing papillary proliferation could be confused with infiltrating carcinoma in frozen sections. Familiarity of pathologists with these lesions is essential for avoiding the overdiagnosis of carcinoma.