Metaplastic Breast Carcinoma Revisited; Subtypes Determine Outcomes: Comprehensive Pathologic, Clinical, and Molecular Review

Surg Pathol Clin. 2022 Mar;15(1):159-174. doi: 10.1016/j.path.2021.11.011. Epub 2022 Jan 31.


Metaplastic breast carcinoma (MpBC) is a heterogeneous group of tumors that clinically could be divided into low risk and high risk. It is important to recognize the different types of MpBC, as the high-risk subtypes have worse clinical outcomes than triple-negative breast cancer. It is important for the pathologist to be aware of the MpBC entities and use the proposed algorithms (morphology and immunohistochemistry) to assist in rendering the final diagnosis. Few pitfalls are discussed, including misinterpretation of immunohistochemistry and certain histomorphologies, particularly spindle lesions associated with complex sclerosing lesions.

Keywords: Diagnostic algorithm; Histologic subtype; Immunohistochemistry; Immunotherapy; Metaplastic carcinoma; Molecular subtypes; Spindle cell lesion; Triple-negative breast cancer.

Publication types

  • Review

MeSH terms

  • Humans
  • Immunohistochemistry
  • Triple Negative Breast Neoplasms* / diagnosis
  • Triple Negative Breast Neoplasms* / genetics
  • Triple Negative Breast Neoplasms* / pathology