The World Health Organizatiοn classification of tumors of the breast is the most widely used pathologic classification system for such disorders. The revision, part of the 4th edition of the WHO series, was published in 2012 and is reflected in the article below 1.
Classification
Epithelial tumors
Invasive breast carcinoma
-
invasive breast carcinoma of no special type (NST)
carcinoma with osteoclast-like stromal giant cells
carcinoma with choriocarcinomatous features
carcinoma with melanotic features
-
classic lobular carcinoma
solid lobular carcinoma
alveolar lobular carcinoma
pleomorphic lobular carcinoma
tubulolobular carcinoma
mixed lobular carcinoma
-
carcinoma with medullary features
atypical medullary carcinoma
invasive carcinoma of no special type with medullary features
carcinoma with signet-ring-cell differentiation
-
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
-
adenomyoepithelioma with carcinoma
Precursor lesions
-
-
classic lobular carcinoma in situ
pleomorphic lobular carcinoma in situ
-
Intraductal proliferative lesions
columnar cell lesions including flat epithelial atypia
Papillary lesions
-
intraductal papilloma with atypical hyperplasia
intraductal papilloma with ductal carcinoma in situ
intraductal papilloma with lobular carcinoma in situ
-
encapsulated papillary carcinoma
encapsulated papillary carcinoma with invasion
-
in situ
invasive
Benign epithelial proliferations
-
adenomas
Mesenchymal tumors
-
benign vascular lesions
atypical vascular lesions
Fibroepithelial tumors
-
benign
borderline
periductal stromal tumor, low grade
Tumors of the nipple
Malignant lymphoma
anaplastic large cell lymphoma, ALK-negative
extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue type
Metastatic tumors
Tumors of the male breast
-
invasive carcinoma
in situ carcinoma
Clinical patterns
See also
breast neoplasms (overview)