Breast short answers

Question 1

Describe the anatomy of breast tissue

Answer 1

Underlying the breast tissue is the pectoral facia and pectoralis major of the chest. The very centre portion of the breast consists of the nipple. The nipple is surrounded by the areola (which darkens during pregnancy and helps the baby latch on and breastfeed). The areola consists of Montomgery’s glands which are a combination of milk and sebaceous glands. The Mongomery’s glands mainly secrete oil to nourish the nipple but can also secrete a small amount of milk during pregnancy.
Under the skin of the breast, there is a layer of adipose tissue known as subcutaneous fat. Between the pectoralis muscle and subcutaneous muscle is the retromammary space (layer). There is also an extensive network of lymphatic vessels in the breast tissue, which is important in regulating the local fluid balance as well as in filtering out harmful substances.
Each breast is divided into 15 -25 lobes that are separated by a fibrous septa. This fibrous septa forms the suspensory ligaments.
Each lobe is divided into many lobules in which are acini (aveoli) and fat cells.
Acini consist of milk-secreting cells arranged around a central lumen, draining into small ducts. Ducts unite to form successively larger structures as they pass toward the nipple.
Before opening to the surface, each of the ducts expand to form a sinus where milk accumulates during nursing.
Acini and ducts are surrounded by specialised smooth muscle cells known as myoepithelial cells. Contraction of these cells causes milk ejection.
The suspensory ligaments (ligaments of cooper) attach the mammary gland to the overlying skin. They are particularly well developed in the superior part of the gland to help support the lobes and lobules.

Question 2

Define staging of breast cancer

Answer 2

Tumour staging is a measure of the extent of the tumour at the time of diagnosis and is based on the features of the primary tumour, involvement of regional lymph nodes and the presence of distant metastasis.
The TNM staging system uses T describing the size of the tumour and any spread of cancer into nearby tissue; N describes spread of cancer to nearby lymph nodes; and M describes the presence metastasis

Question 3

Explain what is meant by grading of a cancer

Answer 3

Histological grading is determined using tubule formation, mitotic count and nuclear pleomorphism and is used to predict the survival rate at 10 years.
Low Grade; 3-5 survival rate;85%
Intermediate grade; 6-7 survival rate; 60 %
High grade; 8-9 survival rate; 45%

Question 4

In relation to the breast; explain the differences between fibrocystic disease and fibroadenoma.

Answer 4

Fibrocystic disease and fibroadenoma are both common benign conditions that usually present between 20-40 years of age.
Patients with fibrocystic disease usually present with painful lumpy breasts that grow and get more painful just before menstruation. It is often bilateral and multifocal.
Patients with fibroadenoma usually present with a painless lump that moves when touched that can become enlarged and painful just before menstruation.
Fibroadenoma results from an excess proliferation of connective tissue and contains both stromal and epithelial cells and though the cause is relatively unknown it is thought to be due to an increased sensitivity to oestrogen.
Fibrocystic disease can be both proliferative and non-proliferative. The proliferative classifications have a slightly higher chance of developing carcinoma than the rest of the general population. Oestrogen dominance of over progesterone is an important factor in causation.

Question 5

In relation to the breast, compare ductal carcinoma in situ with lobular carcinoma in situ. (4 marks)

Answer 5

ductal carcinoma in situ DCIS

• limited to the ducts with no extension beyond the basement membrane
• Accounts for approximately 15-20% of all detected breast cancers.
• Usually identified during routine mammographic screening
• If untreated 30 % would progress to invasive carcinoma.
• Treatment; mastectomy; excellent prognosis
• distorts the lobules into duct like spaces

• lobular carcinoma in situ LCIS
- Malignant cells fill and distend the lobular acini and do not extend beyond the basement membrane.
- occurs predominantly in premenopausal women with a mean age of 45 years
- expands the involved lobules and is more likely to be multifocal and bilateral
- originates in the terminal ductal lobular unit (TDLU)
- usually incidentally-identified histologically in breast tissue biopsied for other reasons
- 1/3 of women with LCIS develop invasive carcinomas
Both ductal and lobular carcinoma are thought to arise from the cells in the terminal duct. DCIS is more likely to be associated with calcifications and as such are more readily identifiable through mammograms whereas LCIS is rarely associated with calcifications and is therefore more likely to be detected at a later stage.

Question 6

List 2 risk factors for breast cancer. (2 marks).

Answer 6

Genetics – The presence of the BRCA1 or BRCA2 genes.

Beginning period before age 12 or experiencing menopause after age 55.

Question 7

What is meant by DCIS?

Answer 7

Breast cancers can be classified morphologically according to whether they have penetrated the basement membrane.
Those that remain within the boundary are carcinoma in situ.
Those that have spread through the membrane are invasive carcinoma.
Ductal carcinoma in situ (DCIS)
- limited to the ducts with no extension beyond the basement membrane
- Thought to arise from the terminal lobular unit
- Accounts for approximately 15-20% of all detected breast cancers.
- Usually identified during routine mammographic screening
- If untreated 30 % would progress to invasive carcinoma.
- Treatment; mastectomy; excellent prognosis
- distorts the lobules into duct like spaces

Question 8

What is the typical pathway of lymphatic spread in the breast

Answer 8

Lymphatic drainage of the breast is important because of its role in the metastasis of cancer cells. Lymph passes from the nipple, areola and lobules of the gland through intramammary nodes and channels to the subareolar lymphatic plexus (Sappey’s Plexus). 
From this plexus drainage takes place through three main routes that parallel venous tributarie
Most lymph (>75%) especially from the lateral side of the breast, drains to the axillary lymph nodes though the axillary (lateral) pathway. As a result spread most commonly follows this pathway.