Background Based on modern series demonstrating low upgrade rates for pure lobular
neoplasia (LN) diagnosed on core needle biopsy (CNB), our institution no longer
recommends routine excision, provided imaging is concordant. This study describes
outcomes in patients managed without surgical excision. Methods From an institutional
database, we identified all patients with a diagnosis of pure atypical lobular hyperplasia
and/or classic lobular carcinoma in situ on CNB managed without surgical excision (ie …

Atypical lobular hyperplasia (ALH) and lobular carcinoma in situ (LCIS) are noninvasive
neoplastic proliferative lesions comprised of generally small, dyscohesive cells originating in
the terminal duct lobular units (TDLUs), with or without pagetoid extension to terminal ducts
[1, 2]. The loss of cell-to-cell cohesion is secondary to absence or dysfunction of E-cadherin.
ALH and LCIS are distinguished from one another by the degree of involvement of the
TDLUs, with ALH showing less involvement (Figs. 14.1 and 14.2). Both lesions are often …