Intracytoplasmic lumina of human breast cancer--a microscopic study and practical application in cytological diagnosis.

Intracytoplasmic lumina (ICLs) of breast carcinoma cells are dominantly noted as rather specific structures in various organella of carcinoma cells. The present study deals with the characteristic patterns of ICLs in the ultrastructural and cytological features of breast carcinomas. Ultrastructural analysis of benign and malignant breast lesions for ICLs revealed a high occurrence of such lumina in the carcinomas. Especially the lumina were frequently noted in cells of scirrhous carcinomas (scirrhous carcinoma: 42 ICLs, medullary tubular carcinoma: 24, papillotubular carcinoma: 17 per each 300 carcinoma cells, mastopathy: 7 ICLs, fibroadenoma: 3, normal mammary gland: 1 or 2 per each epithelial cell). In 55.6% of the cytological cases of scirrhous carcinoma, the tumor cells showed ICLs, whereas such lumina were found at a rate of only 3.4% in benign lesions. These results demonstrate that the detection of ICLs by cytological examination can be useful in the establishment of a diagnosis of scirrhous carcinoma, and in the decision on a breast origin for metastatic tumors.