Histological grading, histochemistry, and electron microscopy of scirrhous carcinoma of the breast.

Twenty-six scirrhous carcinomas of the breast were divided into three histological grades of malignancy; low (Grade I), intermediate (Grade II), and high (Grade III), and the correlation of the grades with histochemical and electron microscopic findings in both tumor cells and host tissues was examined. The tumor cells contained increased amounts of lysosomal acid phosphatase and beta-glucuronidase. This increase was most marked in Grade I and II tumors and the increase was consistent with lysosome-like fine structures. Both intracytoplasmic lumina and microvilli against stroma were characteristic findings of carcinoma cells and they were mostly found in Grade I and II tumors. Segments of intact basal laminae and myoepithelial cells were also found in Grade I and II carcinomas. The stroma contained moderately increased amounts of intracellular acid phosphatase and beta-glucuronidase, independent of tumor grade. The stroma also contained a large amount of acid mucopolysaccharide ground substance, irrespective of the three grades. There was a striking difference in the ultrastructural organization of the stroma between normal and neoplastic tissues. Although fragmented elastic fibers and increased amount of acid mucopolysaccharide granules, and macrophages rich in phagolysosomes were prominent fine structures of the stroma of carcinomas, there was no apparent difference in them among the three grades of malignancy.