mammary lobular neoplasia

Lobular neoplasia (LN) is a term that encompasses both lobular carcinoma in situ and atypical lobular hyperplasia.

These lesions have been shown to constitute both risk indicators and nonobligate precursors of invasive breast cancer, they are relatively uncommon, and are most often identified in specimens taken for other reasons.

Their incidence has increased in the last 2 decades, and novel variants, including a pleomorphic type, have been described.

Immunochemistry

Loss of E-cadherin expression is recognized as a hallmark diagnostic feature of LN and invasive lobular carcinomas, and immunohistochemical (IHC) analysis using anti-E-cadherin antibodies has been proven to be a useful method to differentiate between lobular and ductal lesions.

The frequent use of E-cadherin IHC analysis in routine diagnostic histopathology, however, has resulted in confusion with regard to the actual value of IHC with antibodies against E-cadherin and other proteins of the cadherin-catenin complex.

References

 Lobular Neoplasia of the Breast Revisited With Emphasis on the Role of E-Cadherin Immunohistochemistry. Dabbs DJ, Schnitt SJ, Geyer FC, Weigelt B, Baehner FL, Decker T, Eusebi V, Fox SB, Ichihara S, Lakhani SR, Palacios J, Rakha E, Richardson AL, Schmitt FC, Tan PH, Tse GM, Vincent-Salomon A, Ellis IO, Badve S, Reis-Filho JS. Am J Surg Pathol. 2013 Jul;37(7):e1-e11. PMID: 23759937