Histology of the mammary gland

Question 1

Explain the composition of the breast tissue

Answer 1

Glandular tissue
Fibrous support tissue
Adipose tissue

Question 2

Explain the structure of the nipple

Answer 2

secretions emerge from the surface
12-20 round openings of ducts arranged in a ring
Keratinised stratified squamous epithelium - Nipple
Surrounded by areola
Montgomery’s tubercules -> Large sebaceous glands

Question 3

Explain the breast development

Answer 3

Hormone dependant
Full development at puberty
Nipple and simple duct system at birth

Puberty increase in estrogen
- breast increase in bulk
- Duct system becomes more complex

12-20 distinct lobes
Each lobe consists if duct system with own opening

Question 4

What is a cluster of secretory units called

Answer 4

Lobule

Question 5

Explain the histology of the mammary duct and lobule

Answer 5

Ducts are lined by columnar/cuboidal epithelium
surface layer epithelial cells: Outer myoepithelial cells

Each cluster and duct system = mammary lobule

Question 6

Explain the changes in the breast during the following
- Menstrual cycle
- Pregnancy
- Breastfeeding
- Breastfeeding ceases
- Ageing

Answer 6

Menstrual cycle - Minor transient changes
Pregnancy - Undergoes extensive proliferation
Breastfeeding - TDLU increase in size and complexity, lumen are distended
Breastfeeding ceases - TDLU returns to the normal resting state
Ageing - Fibrocollagenous tissue increases replacing adipose tissue

Question 7

Explain the different types of histological tests used in breast cancer

Answer 7

Increased number of estrogen receptors

H&E staining - Non-specific
Immunochemistry - Labeled antibody is used to detect the presence of tumour cells
Brown staining tumour cells indicative of high levels of estrogen receptors