WHO classification of tumors of the breast

Last revised by Juan Cristobal Valenzuela Claros on 9 Mar 2022

The World Health Organizatiοn classification of tumors of the breast is the most widely used pathologic classification system for such disorders. The current revision, part of the 4th edition of the WHO series, was published in 2012 and is reflected in the article below 1.


Epithelial tumors
Invasive breast carcinoma
  • invasive breast carcinoma of no special type (NST)
    • pleomorphic carcinoma
    • carcinoma with osteoclast-like stromal giant cells
    • carcinoma with choriocarcinomatous features
    • carcinoma with melanotic features​
  • invasive lobular carcinoma
    • classic lobular carcinoma
    • solid lobular carcinoma
    • alveolar lobular carcinoma
    • pleomorphic lobular carcinoma
    • tubulolobular carcinoma
    • mixed lobular carcinoma
  • tubular carcinoma
  • cribriform carcinoma
  • mucinous carcinoma
  • carcinoma with medullary features
    • medullary carcinoma
    • atypical medullary carcinoma
    • invasive carcinoma of no special type with medullary features
  • carcinoma with apocrine differentiation
  • carcinoma with signet-ring-cell differentiation
  • invasive micropapillary carcinoma
  • metaplastic carcinoma
    • metaplastic carcinoma of no special type
    • low-grade adenosquamous carcinoma
    • fibromatosis-like metaplastic carcinoma
    • squamous cell carcinoma
    • spindle cell carcinoma
    • metaplastic carcinoma with mesenchymal differentiation
      • chondroid differentiation
      • osseous differentiation
      • other types of mesenchymal differentiation
    • mixed metaplastic carcinoma
    • myoepithelial carcinoma
  • rare types
    • carcinoma with neuroendocrine features
      • neuroendocrine tumor, well-differentiated
      • neuroendocrine carcinoma, poorly differentiated (small cell carcinoma)
      • carcinoma with neuroendocrine differentiation
    • secretory carcinoma
    • invasive papillary carcinoma
    • acinic cell carcinoma
    • mucoepidermoid carcinoma
    • polymorphous carcinoma
    • oncocytic carcinoma
    • lipid-rich carcinoma
    • glycogen-rich clear cell carcinoma
    • sebaceous carcinoma
    • salivary gland/skin adnexal type tumors
      • cylindroma
      • clear cell hidradenoma
Epithelial-myoepithelial tumors
Precursor lesions
Intraductal proliferative lesions
Papillary lesions
Benign epithelial proliferations
Mesenchymal tumors
Fibroepithelial tumors
Tumors of the nipple
Malignant lymphoma
Metastatic tumors
Tumors of the male breast
Clinical patterns

See also

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