detailed description of anatomy of breast and etiology of breast cancer

2. Embryology
7th Week
• Ectodermal thickening
• Known as “Milk lines”
10th Week
• Gland develops in pectoral region
• Projection of epidermal cells into dermis
5th Month
• 16 to 20 cords develop
• Each proximal end forms lactiferous duct
• Duct opens into a pit and canalisation occurs
• Underlying mesoderm elevates to form nippleBirth

4. An Intro…
• It is a modified sweat gland
• An accessory organ of
female reproductive system
• It has secretory function
during pregnancy and
lactation under the influence
of oestrogen,progesterone
and prolactin

7. Structures of the Breast
NIPPLE
• Conical projection present
just below center of the
breast at the level of 4th
intercostal space
• Contains circular and
longitudinal muscles and rich
sensory nerve endings
AREOLA
• Cirular pigmented area
around the nipple,devoid of
hair.
• Rich in modified sweat
glands which enlarge to form
“montgomery tubules”
PARENCHYMA
• It is made up of glandular
tissue with 15 to 20 lobes
• Each lobe has
alveoli,lactiferous
sinus,lactiferous ducts

8. AXILLARY TAIL OF SPENCE
• Extension of the gland upto axilla
through defect in deep fascia
[Foramen of Langer]
• Has direct contact with anterior
axillary nodes
LIGAMENT OF COOPER
• It is fibrous stroma which anchors
the breast to overlying skin and
underlying pectoral fascia

9. Blood supply
• Lateral thoracic Ar
• Superior thoracic Ar
• Pectoral Br of
acromiothoracic Ar
• Lateral Br of 2nd,3rd,4th
intercostal Ar
• Perforating cutaneous Br
of internal mammary Ar
Venous drainage
• Superficial veins-
axillary,internal mamary
and intercostal vessels
• Posterior intercostal
veins communicates with
paravertebral venous
plexus[Batson’s plexus]

10. NERVE SUPPLY
• Anterior and lateral
cutaneous br of 4th to
6th intercostal nerves
• Milk secretion-
prolactin
LYMPHATIC DRAINAGE
• Axillary nodes-
75%(anterior,central,lat
eral,posterior)
• Internal mammary
nodes-25%
• Others -apical,
interpectoral,
supraclavicular nodes

12. Who are at higher risk??
• It is the 2nd most common cancer in females
• Occurs after 20 yrs, Median age – 47 yrs
• Family history,mainly 1st degree relatives
• Nulliparous and obese woman
• Low oestrogen and alcohol intake
• Early menarche and late menopause
• Early and late 1st child birth

13. • Benign breast ds with atypia,
hyperplasia and epitheliosis
• Pre existing Carcinoma in 1 breast
• Mutation of BRCA1 (chr 17) & BRCA2
(chr 13), BRCA3 and p53 tumour
suppressor genes
• OC pills and HRT for > 5yrs
• Previous therapeutic thoracic radiation
• Associated with Li fraumen’s syndrome
and Cowden’s syndrome