[Histologic classification of breast cancer and its precancerous stages].

A proliferating mastopathy with severe epithelial atypia as well as with so-called radial scars, intraductal papillomatosis, and findings of so-called lobular cancerisation are regarded as possible precursors of mammary carcinoma. The histological differential diagnosis can be difficult between atypical epithelial proliferations in mastopathy and noninvasive intraductal carcinoma, between tubular formations in radial scars and tubular carcinoma, papilloma and papillary carcinoma as well as between primary and secondary lobular cancerisation. Noninvasive and invasive breast carcinomas can be diagnosed according to the WHO classification (12) with a relatively good reproduceability. Besides the histological type, other macroscopic (tumour size, number of metastatically involved lymph nodes, distant metastases), microscopic (tumour grading) as well as biochemical findings (receptor status) are also important for treatment and prognosis of breast carcinoma.