Annual Rhythm in the Growth of Human Breast Carcinomas as Reflected in the Histology of Their Growing Edge

Abstract

This histologic study of breast carcinoma, based on 100 consecutive cases, identifies a dynamic scenario at the tumor edge. Three main types of tumor edge were identified. An inactive edge, seen throughout the year, consisted of tumor cells lying in fibrous tissue that merged into the adjacent fatty tissue. An infiltrative edge was characterized by an acute microvascular response and the presence of fine lymph channels often containing embolic tumor cells. A capsular edge showed sharp tumor demarcation accompanied by proliferation and followed by lymphocyte infiltration. Infiltrative edges were found mainly in the first half of the year, and capsular edges in the second. Thus, the growth of individual breast carcinomas appears to be the result of a common series of growth phases at their advancing edge that follow an annual cycle.