This document outlines the classification of breast tumours according to histopathology, grade, stage, receptor status, and DNA. It describes the WHO histological classification including epithelial and stromal tumours of the breast, as well as tumours of the male breast and nipple. Benign and malignant epithelial lesions are defined. Malignant lesions include carcinoma in situ (DCIS and LCIS) and invasive carcinoma. Molecular subtypes and specific tumour types such as lobular carcinoma are also detailed. The classification of stromal tumours, tumours of the male breast, and nipple are summarized.

1. CLASSIFICATION
OF BREAST
TUMOURS
PRADEEP S

2. • Histopathology
• Grade
• Stage
• Receptor status
• DNA based

3. WHO
HISTOLOGICAL
CLASSIFICATION
OF
BREAST
TUMOURS

6. • Epithelial tumours
• Stromal tumours
a) Intralobular
b) Interlobular
• Tumours of male breast
• Tumour of nipple
• Others
a) Lymphocytes
b) Skin
c) Metastatic tumours

7. • Benign epithelial lesions
a) Non proliferative changes
b) Proliferative breast disease without atypia
c) Proliferative breast disease with atypia
• Malignant epithelial lesions
a) Carcinoma in situ
b) Invasive( infiltrating ) carcinoma

8. Apocrine cyst

9. • Epithelial hyperplasia
• Sclerosing adenosis
• Complex sclerosing lesion
• papilloma

14. Atypical ductal hyperplasia Atypical lobular hyperplasia

15. A. Carcinoma in situ
 Ductal carcinoma in situ
a) Comedo DCIS
b) Non comedo DCIS
 Lobular carcinoma in situ
B. Invasive( infiltrating) carcinoma

16. Comedo in situ

17. Cribriform DCIS Micropapillary DCIS

18. Molecular subtypes:
 ER- positive, HER-2 negative(luminal)
a) Low proliferation
b) High proliferation
 HER-2 positive
 ER-negative, HER-2 negative

19. ER- positive tumours:
 Lobular carcinoma
 Mucinous (colloid) carcinoma
 Tubular carcinoma
 Papillary carcinoma

20. Lobular carcinoma Colloid carcinoma
Tubular carcinoma papillary carcinoma

21. Apocrine carcinoma Micropapillary carcinoma

22.  Medullary carcinoma
 Secretory carcinoma
 Spindle cell carcinoma
 Low grade adenosquamous carcinoma
 Adenoid cystic carcinoma

23. Medullary carcinoma Secretory carcinoma

25. A. Intralobular
 Fibroadenoma
 Phyllodes tumour
B. Interlobular
 Benign tumour
 Malignant tumour

26. Fibroadenoma Phyllodes tumour

27. Benign:
 Myofibroblastoma
 Lipomas
 Fibromatosis
Malignant:
 Angiosarcoma
 Rhabdomyosarcoma
 Liposarcoma
 Leiomyosarcoma
 Chondrosarcoma
 Osteosarcoma

28. A. Gynecomastia(benign)
B. Carcinoma:
 In situ
 invasive

29. A. Benign:
 Nipple adenoma
 Syringomatous
adenoma
B. Paget’s disease of
nipple

30. Lymphocytes:
 Non- Hodgkin lymphoma
Skin:
 Melanomas
Metastases to breast:
 Melanoma
 Ovarian cancers