Atlas of breast cancer early detection

The International Classification of Diseases for Oncology, 3rd edition (ICD-O-3) published by IARC/WHO is internationally recognized as the definitive classification of neoplasms. ICD-O-3 is used principally in tumour or cancer registries for coding the site (topography) and the histology (morphology) of neoplasms, usually obtained from a pathology report. ICD-O-3 is a multi-axial classification of the site, morphology, behaviour, and grading of neoplasms.
The topography code describes the anatomical site of origin of the tumour.

ICD-O-3 topography site codes for breast C50.0: Nipple C50.1: Central portion of breast C50.2: Upper inner quadrant of breast (UIQ) C50.3: Lower inner quadrant of breast (LIQ) C50.4: Upper outer quadrant of breast (UOQ) C50.5: Lower outer quadrant of breast (LOQ) C50.6: Axillary tail of breast C50.7: Overlapping lesion of breast C50.9: Breast, NOS (excludes skin of breast C44.5); multifocal neoplasm in more than one quadrant of the breast.

The WHO Classification of Tumours of the Breast, 5th edition is generally used classify tumours into various subtypes based on tumour architecture, cytonuclear features, and stromal features (WHO Classification of Tumours Editorial Board. Breast tumours. Lyon (France): International Agency for Research on Cancer; 2019. (WHO classification of tumours series, 5th edition; vol. 2))
A breast carcinoma showing a special histological pattern in more than 90% of the tumour is designated as a pure special type. Most breast cancers do not show such specific features and are designated as invasive breast carcinoma of no special type.
The histological subtypes of invasive breast carcinoma are as follows:

• Invasive breast carcinoma of no special type
• Microinvasive carcinoma
• Invasive lobular carcinoma
• Tubular carcinoma
• Cribriform carcinoma
• Mucinous carcinoma
• Mucinous cystadenocarcinoma
• Invasive micropapillary carcinoma
• Carcinoma with apocrine differentiation
• Metaplastic carcinoma
• Encapsulated papillary carcinoma with invasion
• Solid papillary carcinoma with invasion
• Invasive papillary carcinoma
• Rare and salivary gland type tumours
• Neuroendocrine carcinoma.