Breast pathology Histopathology of the breast Description and significance of the components of the report Pathological staging (according to the 2017 TNM classification of malignant tumours, 8th edition; UICC)
Classification of tumour, node, and metastasis (TNM) by pathological examination of the resected tissue is denoted by use of a lowercase p prefix:
- pT1: Tumour 2 cm or less in greatest dimension.
- pT2: Tumour more than 2 cm but not more than 5 cm in greatest dimension.
- pT3: Tumour more than 5 cm in greatest dimension.
- pT4: Tumour of any size with direct extension to chest wall or skin.
- pN0: No regional lymph node metastasis.
- pN1: Metastasis in 13 ipsilateral axillary lymph node(s), and/or in internal mammary nodes with microscopic metastasis detected by sentinel lymph node dissection but not clinically apparent.
- pN2: Metastasis in 49 ipsilateral axillary lymph nodes, or in clinically apparent ipsilateral internal mammary node(s) in the absence of axillary lymph node metastasis.
- pN3: Metastasis in 10 or more ipsilateral axillary lymph nodes, or in infraclavicular lymph nodes; or in clinically apparent ipsilateral internal mammary nodes in the presence of 1 or more positive axillary lymph node metastasis or in more than 3 axillary lymph nodes with clinically negative, microscopic metastasis in internal mammary nodes; or in ipsilateral supraclavicular lymph nodes.
- pM1: Distant metastasis (applicable only if biopsy positive at metastatic site).
The following TNM descriptors are required only if applicable:
- m (multiple): In cases of multiple simultaneous tumours in one breast, the tumour with the highest T category should be classified and the multiplicity or the number of tumours should be indicated in parentheses, e.g. T2(m) or T2(5).
- r (recurrent): When a tumour is staged after a documented disease-free interval.
- y (post-treatment): Applies to staging following initial multimodality (e.g. after neo-adjuvant therapy) therapy. Add as prefix to the pTNM descriptor, e.g. ypTNM.
- In simultaneous bilateral cancers, each tumour is classified independently.
Click on the pictures to magnify and display the legends
Click on this icon to display a case study
IARC, 150 Cours Albert Thomas, 69372 Lyon CEDEX 08, France - Tel: +33 (0)4 72 73 84 85 - Fax: +33 (0)4 72 73 85 75
© IARC 2023 - All Rights Reserved