Breast(mammary gland)

By

Dr Manah Chandra Changmai MBBS MS

Breast are present bilaterally inpectoral region

They are modified sweat glands

In male and immature female,breastare rudimentary

After puberty,female breast are fullydeveloped.

Mammary gland

Extent:Vertically-2nd to 6th ribshorizontally- from lateral border of sternumTo mid-axillary line along fourth rib.

Mammary bed: Rest upon following structures1.Pectoralis major- In medial two thirds2.Serratus anterior- lateral one third.3.External oblique aponeurosis- In infero-medial quadrant.

Female mammary gland

Retro-mammary space:Intervenes between base of the gland and the deep Fascia covering the mammary bed.

Axillary tail of spence:-occasionally present-projection from the upper and outer quadrant of the gland.-enters the axilla through an opening in the axillary fascia(foramen of langer).

Features in the skin overlying the breast

Nipple : -conical or cylindrical projection below the centre of the breast.-usually present at the fourth intercostal space.-pierced by 15-20 lactiferous ducts.-contains circular and longitudinally disposed smooth muscle.

Areola-pigmented circular area of the skin around the base of the nipple.-irreversibly darkened after first pregnancy.-outer margin contains modified sebaceous gland -these galnds enlarged during pregnancy and lactation(tubercles of montgomery)

Structure of the breast

Made up of three parts.

1.Glandular tissue

2.Fibrous tissue

3.Interlobar fatty tissue.

Glandular tissue

Lobes-15-20 lobes pyramidal in shape drained by a lactiferous duct.-All lobes converge towards the areola.-Near the areola each lactiferous duct dilates to form lactiferous sinus.-each duct drain open onto the nipple..

Lactiferous duct and Lobules-Each lactiferous duct drains a segmental segments of smaller duct.-segmental duct divides into small terminal duct-terminal duct gives rise to numerous sectretory pouches (alveoli) like cluster of grapes.-breast parenchyma drain by lactiferous duct is known as lobules.-the ducts possess myopeithelial cells.

From birth to pre-pubertal life: lactiferous ducts without alveoli

At puberty: Ducts undergo branching,form solid spherical masses precusors of alveoli.

In pregnancy: Further proliferation,epithelial growth of terminal duct increase in the alveoli per lobule.

During lactation: Alveoli are distended by milk secretion,line by single layer of epitheium.

After lactation: Glandular tissue returns to resting condition.

Structural differentiation of mammary gland

Supports lobes and form septa’s

Septa anchor the parenchyma to overlyingskin.

These fibrous bands are called ligament ofcooper.

Fibrous tissue

Interlobar fatty tissue

Makes the organ rounded in contour

Absent beneath areola and nipple.

Peu de orange

Histology of breast

Arteries

Branches of the axillary artery, the internal thoracic artery, and some intercostal arteries.

Veins

Forms circular venous plexus around the areola

Blood drains in veins which accompany the corresponding arteries that supply the breast, i.e. to the axillary, internal thoracic and intercostal veins.

4th to 6th intercostal nerves.

Innervation of breast

Consists of two sets

Draining the parenchyma ofbreast including nipple andareola

Draining overlying skin excludingnipple and areola

75% of lymphatics drain into axillary nodes.

20% drain into parasternal(internal mammary) from both medial and lateral parts of the gland.

5% from lateral and posterior part drain into posterior intercostal nodes.

From parencyma of the breast

From the outer part : Axillary nodes

From the upper part: Supraclavicular group of lymph nodes

From the inner part: Parasternal nodes

From the lower part: communicates with subperitoneal lymphatic plexus,drains to sub-diaphragmatic lymph nodes.

From the overlying skin

Male breast

Composed of duct system without alveoli.

Breast tissue doesnot extent beyond the marginsof alveoli

Hypertrophi of male breast observed in klinefelter’ssyndrome.

Male breast richly supplied by lymphatics.

Prognosis of breast carcinoma in male worst thanin females.

Gynaecomastia

Causes :

Thyroid problems

Kidney and liver disease

Klinefelter’s syndrome

Obesity

Drugs

At seventh week of intra uterine life two ectodermal milk ridges appearon each side from axillae to inguinalregion.

Amastia : bilateral agenesis of mammary gland.

Polythelia: supernumerary nipples may be found irregularly over the breast and along milk ridges.

Polymastia: accessory breast may occur along milk ridges,occasionally functional.

AmastiaPolythelia

Polymastia

Right accessory breast Left accessory breast

Polymastia

Frequency of breastcarcinoma at various sites

Palpation of axillary regionfor enlarged nodes

Ductal carcinoma

Mammography Only 15-20% of studies are abnormal High % are false positive

To be seen on mammogram, tumor isusually 8-10 years old

Expensive

Factors Favoring Breast ConservingTherapy:

Patient preferenceTumor size and location favorableUnifocal tumorSmall or no intraductal portionPatient cannot tolerate general anesthesia

Factors Favoring Mastectomy:

Patient preferenceTumor size and location not favorableMultifocal tumorExtensive intraductal componentInability to observe postopInability to ahcieve negative marginsContraindication for radiotherapy

Cosmetic procedures include breast lifts (mastopexy), breast augmentation with implants, and procedures that combine both elements. Implants containing either silicone gel or saline are available for augmentation and reconstructive surgeries

Treatment of carcinoma of breast

Thank you