Lobular Neoplasia Morphology and Management

Context.-Lobular neoplasia encompasses a spectrum of disease, including atypical lobular hyperplasia and lobular carcinoma in situ. Although classic forms of lobular neoplasia are predominantly heralded as a risk marker, the pleomorphic form of lobular carcinoma in situ is generally regarded as a more aggressive subtype and a possible cancer precursor, and thus is treated in a manner more similar to ductal carcinoma in situ than classic forms of lobular neoplasia. Objective.-To focus on the morphologic spectrum of lobular neoplasia as highlighted by 3 cases and current management recommendations. Areas of diagnostic challenge and controversy are addressed. Data Sources.-A review of the pertinent published literature and current national guidelines was conducted. Conclusions.-Correct classification of classic lobular neoplasia and pleomorphic lobular carcinoma in situ is critical because of differences in clinical management, with current treatment strategies focused on risk reduction for patients with classic lobular neoplasia and eradication of the lesion for those with pleomorphic lobular carcinoma in situ.