Breast malignant, males, children
Breast cancer
WHO classification of breast tumors

Author: Belinda Lategan, M.D. (see Authors page)

Revised: 20 October 2016, last major update September 2014

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: WHO classification of breast tumors

Cite this page: WHO classification of breast tumors. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/breastmalignantwhoclassification.html. Accessed December 4th, 2016.
Definition / General
  • Updated 2012 WHO WHO Classification of Tumors of the Breast
    • First edition to separate breast tumors from tumors of female genital organs
    • Takes into account newer developments in the understanding of specific lesions
    • Includes staging recommendations in more contentious situations i.e. pT- stage encapsulated papillary carcinoma as Tis as opposed to based on size
    • Updated information on molecular pathology, expression profiling and molecular classification of breast tumors; however, focus remains on morphologic classification
    • Updates on prognostic markers
      • Does not reflect most recent 2013 ASCO / CAP recommendations for interpretation of HER2 tests

2012 WHO Classification of Tumors of the Breast
  • Epithelial tumors
    • Microinvasive carcinoma

  • Invasive breast carcinoma
    • Invasive 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
    • Cribiform carcinoma
    • Mucinous carcinoma
    • Carcinoma with medullary features
      • Medullary carcinoma
      • Atypical medullary carcinoma
      • Invasive carcinoma NST with medullary features
    • Carcinoma with apocrine differentiation
    • Carcinoma with signet ring differentiation
    • Invasive micropapillary carcinoma
    • Metaplastic carcinoma of no special type
      • Low-grade adenosquamous carcinoma
      • Fibromatosis like metaplastic carcinoma
      • Squamous cells 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
    • Pleomorphic adenoma
    • Adenomyoepithelioma
      • Adenomyoepithelioma with carcinoma
    • Adenoid cystic carcinoma

  • Precursor lesions
    • Ductal carcinoma in situ
    • Lobular neoplasia
      • Lobular carcinoma in situ
        • Classic lobular carcinoma in situ
        • Pleomorphic lobular carcinoma in situ
      • Atypical lobular hyperplasia

  • Intraductal proliferative lesions
    • Usual ductal hyperplasia
    • Columnar cell lesions including flat epithelial atypia
    • Atypical ductal hyperplasia

  • Papillary lesions
    • Intraductal papilloma
      • Intraductal papilloma with atypical hyperplasia
      • Intraductal papilloma with ductal carcinoma in sit
      • Intraductal papilloma with lobular carcinoma in situ
    • Intraductal papillary carcinoma
    • Encapsulated papillary carcinoma
      • Encapsulated papillary carcinoma with invasion
    • Solid papillary carcinoma
      • In situ
      • Invasive

  • Benign epithelial proliferations
    • Sclerosing adenosis
    • Apocrine adenosis
    • Microglandular adenosis
    • Radial scar / complex sclerosing lesion
    • Adenomas
      • Tubular adenoma
      • Lactating adenoma
      • Apocrine adenoma
      • Ductal adenoma

  • Mesenchymal tumors
    • Nodular fasciitis
    • Myofibroblastoma
    • Desmoids type fibromatosis
    • Inflammatory myofibroblastic tumor
    • Benign vascular lesions
      • Haemangioma
      • Angiomatosis
      • Atypical vascular lesions
    • Pseudoangiomatous stromal hyperplasia
    • Granular cell tumor
    • Benign peripheral nerve sheath tumors
      • Neurofibroma
      • Schwannoma
    • Lipoma
      • Angiolipoma
    • Liposarcoma
    • Angiosarcoma
    • Rhabdomyosarcoma
    • Osteosarcoma
    • Leiomyoma
    • Leiomyosarcoma

  • Fibroepithelial tumors
    • Fibroadenoma
    • Phyllodes tumor
      • Benign
      • Borderline
      • Malignant
      • Periductal stromal tumor, low grade
    • Hamartoma

  • Tumors of the nipple
    • Nipple adenoma
    • Syringomatous adenoma
    • Paget disease of the nipple

  • Malignant lymphoma
    • Diffuse large B cell lymphoma
    • Burkitt lymphoma
    • T cell lymphoma
      • Anaplastic large cell lymphoma, ALK negative
    • Extranodal marginal-zone B cell lymphoma of MALT-type
    • Follicular lymphoma

  • Metastatic tumors
  • Tumors of the male breast
    • Gynaecomastia
    • Carcinoma
      • Invasive carcinoma
        • In situ carcinoma

  • Clinical patterns
    • Inflammatory carcinoma
    • Bilateral breast carcinoma