Pathologic types of breast cancer: their prognoses

Mammary epithelium gives rise to a wide variety of histologically diverse carcinomas. Some types are associated with predictable patterns of clinical behavior, and it is important that these be recognized since, in many instances, therapeutic modifications are indicated. Among the kinds of breast carcinoma generally considered to have prognoses more favorable than average are adenoid cystic carcinoma, tubular carcinoma, juvenile secretory carcinoma, and perhaps medullary carcinoma with lymphoid stroma. Some of the prognostically unfavorable carcinomas are carcinoma with sarcomatoid metaplasia and inflammatory carcinoma. In applying this information to individual clinical situations, it is critical that a standard classification be consistently used and that its criteria be strictly observed. The 1981 edition of the classification promulgated by the World Health Organization while not flawless, is recommendable, since it includes both concise verbal definitions and admirably clear photomicrographs. Whatever the system of terminology chosen, it should be one equally acceptable to the pathologist responsible for histologic diagnosis and the physician responsible for treatment, and it should be clearly understood by both of them. These special types of carcinoma constitute only a minority of all breast cancers.