[Histogenesis of lobular cancer of the breast. Histoenzymatic and ultrastructural study of a muciparous cell invasive epithelioma].

A comparative light microscopy, histoenzymological and ultrastructural study enabled the authors, in a case of invasive lobular carcinoma of the breast, to emphasise certain special morphological traits of this tumour type and to make a contribution to the understanding of its histogenesis. By light microscopy, the only special features of the case were the abundance of mucus secreting tumour cells in the perilobular infiltrating zones and in the stromal texture with marked perigalactophoric hyalinosis and active elastic neogenesis. From an ultrastructural standpoint, intralobular malignant zones contained epithelial type cells, rich in microfilaments and with numerous desmosomal junctions. Two other cell types were identified at the periphery of the lobules. On consisted of round cells with intracytoplasmic cavities filled with mucus (signet ring cells). This group, in common with the intralobular cells, contained abundant amounts of alkaline phosphatase. The other consisted of elongated "pseudo-fibroblastic" cells, rich in microfibrils and in granular ergastoplasm with secretion at points of contact of collagen and elastin. These cells showed marked ATPase activity. They no doubt represented "hybrid" cells, intermediate in terms of their morphology and enzyme activity between myoepithelial and epithelial cells. These findings would thus appear to offer arguments in favour of the double cell origin -- duct and myoepithelial -- of lobular carcinoma.