[Organ-specific ultrastructural cellular signs of cancerous breast tumors].

The ultrastructural analysis of 40 cases of mammary carcinomas revealed two groups of cells: with ultrastructural organ specific features (differentiated cells) and without them (undifferentiated cells). Intracytoplasmic lumens, secretory granules (lipid, protein, and mixed lipid-protein), and myoepithelial cells are the main organ specific features of mammary carcinomas. The histospecific features showing the epithelial origin of the tumor cells include cell-to-cell contacts, ductules, intercytoplasmic lumens with microvilli, and fragments of basal lamina. These ultrastructural features of mammary carcinomas can facilitate the differential diagnosis of tumors of this organ.