Diagnostic problems in breast pathology: the benefit of ultrastructural and immunocytochemical analysis.

This report deals with the diagnostic importance of intracytoplasmic lumina. The separation between tubular carcinoma and sclerosing adenosis, and the ultrastructural features of variants of lobular carcinoma are discussed. The role of electron dense granules as well as other markers for neuroendocrine cells are evaluated, and finally, the difficult separation of both small-cell and spindle cell tumors is considered.