Carcinoma of the breast arising in fibroadenomas, with emphasis on lobular carcinoma:A clinicopathologic study

This paper deals with the clinicopathologic features exhibited in 7 cases of carcinoma of the breast arising in fibroadenomas. The average age of the patients was 44, a figure similar to that reported in the only other comparable study, approximately 20 years older than the peak incidence of fibroadenomas in the general female population. Lesions were uniformly asymptomatic and varied in known duration from 10 days to 10 years. Clinical and gross pathologic examinations were characteristic of fibroadenoma. The predominant pathologic expression of the carcinoma developing within a fibroadenoma appears to be lobular rather than ductal and is primarily one of lobular carcinoma in situ, an occurrence which supports the concept that a portion of the mammary epithelium within some fibroadenomas is of terminal duct and lobular derivation. The clinical and pathologic features of lobular carcinoma are reviewed, and recommendations for appropriate management of both lobular and ductal neoplasms are offered.