Morphological and immunohistochemical studies of intraductal proliferations of the breast, especially on the carcinogenesis of papilloma and structural atypism of carcinoma

Surgical specimens from the patients with intraductal proliferations were subjected to 3-dimensional (3-D) morphological and immunohistochemical studies to demonstrate the features of papilloma prone to cancerous change and the structural atypism of carcinoma for discriminating from benign proliferations. Two types of papillomas were classified into the peripheral papilloma originated from terminal ductal lobular units (TDLU) and the central papilloma originated from large ducts. The patients with peripheral papilloma had an increased incidence of cancer coexisted, whereas none of the patients with central papilloma did. These observations suggest that the peripheral papilloma is susceptible to cancerous change. Reconstructions of microscopic carcinomas suggest that the origin of ductal carcinoma is TDLU, especially intralobular terminal ducts and ductules. Reconstructions of glandular structures revealed that there was a spectrum from the complex glandular pattern of papilloma and papillomatosis, through borderline lesion, to the cribriform pattern of carcinoma. To describe our 3-D figures we employed the terms "luminal network in papilloma vs. porous structure in carcinoma". Lectin-binding profile in papilloma was an irregular network structure along the luminal borders and apical cytoplasmic surfaces, while that in carcinoma was not only a cribriform but also a rosette structure along the supranuclear cytoplasms and intracytoplasmic lumina. Such binding-patterns of lectins can be a stable criterion to distinguish carcinoma from benign proliferations.