Evolving concepts in the management of lobular neoplasia.

Lobular neoplasia broadly defines the spectrum of changes within the lobule, ranging from atypical lobular hyperplasia (ALH) to lobular carcinoma in situ (LCIS). This continuum of lesions is associated with an increased risk for developing subsequent invasive breast cancer, with the magnitude of that risk corresponding to the degree of proliferative change. The associated risk for developing invasive breast cancer after a diagnosis of lobular neoplasia is multicentric, bilateral, and equal in both breasts. Lobular neoplasia itself may transform into invasive carcinoma, although the frequency of this occurrence is unknown. Thus, lobular neoplasia is a risk factor for invasive breast cancer and may be a precursor lesion in unusual circumstances. The management of ALH and LCIS depends on the setting in which they are encountered. When ALH and LCIS are diagnosed after core needle breast biopsy, wire localization for surgical excision is required for definitive diagnosis because rates of histologic underestimation approach those of atypical ductal hyperplasia (ADH). When diagnosed on surgical biopsy, ALH and LCIS generally do not require further intervention, even when present at a surgical margin. However, bilateral breast cancer risk must be considered, especially when patients have a family history of breast cancer. In selected situations, bilateral prophylactic mastectomy with or without reconstruction may be considered when atypical hyperplasia or LCIS is diagnosed. Although this reduces risk for developing subsequent breast carcinoma by 90%, patients selected for prophylactic mastectomy represent a small subgroup of lobular neoplasia patients and generally have other risk factors, such as strong family history or evidence of genetic predisposition.