[Carcinoma and fibroadenoma of the breast].

Eight cases of breast carcinoma coexisting with fibroadenoma were retrieved from the files of the Division of Pathology from 1957 to 1987. In 3 patients (Group I) the lesion was within the fibroadenoma and in the remaining 5 patients, adjacent to it (Group II: synchronic carcinomas). All patients were females. During the same period, 987 fibroadenomas and 2004 carcinomas were diagnosed: 0.30% of the fibroadenomas developed carcinoma within the epithelial component and 0.15% of the carcinomas originated in the fibroadenoma's epithelium. The mean age was 39 years for in situ lesions and 45.5 years for infiltrating carcinoma with a general mean age of 43.3 years, 20 years older than the peak age of fibroadenoma. In Group I, there were 3 in situ lesions, 1 lobular and 3 ductal (Table 1). Two of the three patients had another coexisting gynecologic malignancy. In Group II all cases had infiltrating carcinomas, one lobular, 3 ductal and 1 mixed lobular and ductal (Table 1). The adjacent breast tissue showed associated pathology in all cases: multiple fibroadenomas, fibrocystic diseases, sclerosing adenosis, infiltrating ductal carcinoma and/or lobular hyperplasia. Different hypotheses from the literature were analysed concerning an association between carcinoma and fibroadenoma. A casual association is suggested by the low percentage of carcinomas developing in fibroadenomas as well as the low percentage of carcinomas originating from fibroadenomas.