Comparative ultrastructure of atypical ductal hyperplasia, intraductal carcinoma, and infiltrating ductal carcinoma of the breast

Abstract

Atypical ductal hyperplasia, intraductal carcinoma, and frankly infiltrating ductal carcinoma of the breast were studied by electron microscopy. Atypical ductal hyperplasia was characterized by the presence of very abundant, irregular and frequently giant, polypoid microvilli. Intraductal carcinoma cells displayed very complex cell interdigitations. Conspicuous intracytoplasmic lumina were exclusively observed in infiltrating carcinoma cells. Anomalies in the cell membrane and its derivatives appear to be a common denominator of all these lesions. Both loosely arranged and tightly packed cytoplasmic filaments were much more abundant in infiltrating carcinoma cells than in either atypical hyperplasia or intraductal carcinoma. Phagocytosed leukocytes were often found within carcinomatous breast cells. The possible connection of this observation with immunologic phenomena remains obscure. Further ultrastructural studies may conceivably develop some of these features into more accurate diagnostic criteria for doubtful breast lesions.