general features, extend, relations, parts, development, glandular tissue, ducts, lobules, structure in different stages

1. Mammary gland
Histology

2. General features
 A pair of modified sweat glands.
 Location
 Covered with skin , nipple and areola
 In males; rudimentary
 Females; grow after puberty

3. Extend
 Vertical; second to sixth ribs
 Horizontal; sternal margin to mid
axillary line

4. Parts and relations
 Broad base- on chest wall
 Pointed apex- bears the nipple
 Axillary tail of Spence- passing through the
foramen of Langer
 Rest on pectoral fascia
 Retro mammary space
 Mammary bed

5. Development
 From ectodermal milk line

6. Microscopic features
mammary
gland
parenchyma
stroma
parenchyma
lactiferous
gland
ducts

7. Glandular tissue
 Compound tubulo alveolar / recemose
 15-20 pyramidal lobes
 Each drained by separate ducts-
lactiferous duct
 Near the areola – lactiferous sinus

8. Ducts
Lactiferous
duct
Segmental
ducts
Terminal
ducts

9. Lobule
 Area drained by one terminal
duct
 Separated by fibro-fatty
connective tissue
 TDLU- terminal duct lobular unit
 Cluster of secretory alveoli
 Surrounded by intra lobular
stroma

10. Structure in different stages
Before puberty
• Ducts only
• Some amount of stroma
b/w puberty
&first pregnency
• Ducts proliferates
• At the end solid masses of polyhedral cells
• Bulk is fat and connective tissue
Resting stage
• Dense connective tissue and fat
• Some alveoli developed
• Cuboidal epithelium and small lumen

11. Resting stage

12. Resting stage

13. Lactacting / active stage
 Elevated estrogen and progesterone
 Proliferation of terminal ducts and lobules
 Increase in no. of alveoli per lobule
 alveoli mature
 In third trimester; hypertrophy ,secretion of ”pre milk”
 Colostrum
 rich in protein, vitamin A, Na, chloride
 Low in K, carbohydrates, lipids than milk

14.  Alveoli – cells are cuboidal in resting stage 
changes to columnar in the active stage
 Once secretions are poured into lumen seen
as cuboidal
 Myoepithelial cells- b/w the cells and
membrane
 Helps in secretion of milk
 Lipids apocrine
 Proteins merocrine

15. Active stage

16. Active mammary gland

17. Duct system
 Lactiferous duct- stratified sq keratinisedstratified cuboidal
 Larger ducts - stratified cuboidal
 Smaller ducts – simple cuboidal

18. Resting mammary gland Active mammary gland
stroma More connective tissue, less
glandular tissue
More glandular tissue, less
connective tissue
Secretory units Secretory units are few, poorly
developed
Numerous and well developed
alveoli Lined by cuboidal epithelium
and narrow lumen
Columnar epithelium and wider
lumen
Excretory ducts Narrow and empty Wider and filled with mlk

19. Post lactational
Involution
a) Reduced cell size of epithelium –Autophagolysis
b) Reduced cell number by apoptosis
c) Reversion to resting state
d) Increase in elastic tissue

20. Applied histology
 Fibro adenoma
 Benign tumor of fibrous and epithelial elements
 Most common benign lesion of breast
 Most pts are at 15-30 yrs of life
 Solitary , descrete , freely mobile nodule
 Carcinoma
 Perimenopausal age
 Solitary, painless , hard lump

21. Fibroadenoma

22. Carcinoma

23. Galactogram

24. Mammogram

25. Digital mammogram