Different types of Breast cancer

"Breast cancer" actually includes a large number of different pathologies, requiring appropriate treatment.

The most frequent are ductal (without specific type) or lobular carcinomas.
A distinction is made between ductal and lobular carcinomas "in situ" from invasive or infiltrative carcinomas.

Carcinomas in situ.
Cell proliferation is limited inside lobules or canals.
The risk of damage to the lymph nodes in the armpit is theoretically zero (like the risk of distant metastasis).
Lobular carcinomas in situ are considered to be risk factors for breast cancer and do not require specific treatment.

Invasive carcinomas.
The tumor infiltrates the tissue around the canals or lobules. There is a risk of extension to the axillary nodes and metastasis.
This risk depends on the biological characteristics of the tumor (size, histological type, grade, presence of hormone receptors, over-expression of HER2, presence of vascular emboli, etc.)

Today we mainly use molecular classification.
It is based on the presence of estrogen receptors, progesterone receptors, or an over-expression of the HER2 protein (EGFR receptor).

We distinguish as follows:

- LUMINAL A cancer
It is characterized by the presence of estrogen and progesterone receptors and an absence of HER2 overexpression. It is the most common form. Her prognosis is usually good.

- LUMINAL B cancer
It is characterized by the presence of estrogen or progesterone receptors (to a lesser degree compared to luminal cancers A) and an absence of over-expression of HER2.

- BASAL cancer
It is characterized by the absence of estrogen and progesterone receptors, as well as the absence of over-expression of HER2.
It's usually called "triple negative"

- Cancer over-expressing HER2
It is characterized by an over-expression of HER2, regardless of the expression of hormone receptors.

This classification is important for the choice of treatments.
- Hormone therapy can be given in cancers expressing hormone receptors (luminal cancers A or B as well as certain cancers over-expressing HER2).
- Targeted anti-HER2 therapies are indicated for cancer overexpressing HER2.
- Chemotherapy is the basis of medical treatment for basal cancers.

La totalité des cancers décrits au niveau du sein est donnée par la classification OMS.

HISTOLOGICAL CLASSIFICATION OF BREAST TUMORS

I. EPITHELIAL TUMORS

A. BENIGNES
l. Intracanal papilloma
2. Adenoma of the nipple
3. Adenoma
at. Tubular
b. Lactant
4. Others

B. MALIGNES
1. Non-infiltrating
at. Intracanal carcinoma
b. In situ lobular carcinoma
2. Infiltrators
at. Invasive ductal carcinoma
b. Invasive ductal carcinoma with predominant intracanal component
vs. Invasive lobular carcinoma
d. Mucinous carcinoma
e. Medullary carcinoma
f. Papillary carcinoma
g. Tubular carcinoma
h. Cystic adenoid carcinoma
i. Secreting [juvenile] carcinoma
j. Apocrine carcinoma
k_ Metaplastic carcinoma
L of squamous type
11. spindle cell type
you. chondroid and bone type
iv. mixed type6
l. Others
3. Paget's disease of the nipple

II. EPITHELIAL TUMORS AND MIXED CONJUNCTIVES

A. FIBRO-ADENOMA.
B. PHYLLODE TUMOR (phyllode cystosarcoma]
C. CARCINOSARCOME

III. MISCELLANEOUS TUMORS

A. SOFT TUMORS
B. SKIN TUMORS
C. TUMORS OF HEMATOPOIETIC TISSUES AND LYMPHOIDS
IV. UNCLASSIFIED TUMORS
V. BREAST DYSPLASIA / FIBROKYSTIC DISEASE

VI. PSEUDOTUMORAL LESIONS

A. ECTASIA CHANNEL
B. INFLAMMATORY PSEUDOTUMEUR
C. HAMARTOME
D. GYNECOMASTY
E. OTHERS