Age-Related Changes of the Breast in US and MR

IOANNA TZOVARA, MD Radiologist

IASO General Hospital, Athens, Greece

Embryology of the Breast

Changes in the Breast during Childhood

Breast Development during Puberty

Mature Breast

Menstrual Cycle Breast Changes

Changes in the Breast during Pregnancy

Changes in the Breast during and after Lactation

Changes in the Breast during and after Menopause

Changes in the Breast with Hormone Replacement Therapy

At about the sixth week of embrionic life, breast precursor develops from ectodermal origin

The “milk line” extends from the axillary area to the groin region

Portions of the milk line atrophy except in the region of the 4th intercostal space, from which

mammary tissue develops




Mature Breast






Branching of main ducts (Terminal Duct Lobular Units) which consist of an interlobular duct and an

associated lobule

Branching of main ducts (Terminal Duct Lobular Units)

Proliferation and enlargement of adipose cells

Increasing of stroma and blood vessels

From infancy to just before puberty, there is no difference between the female and male

breasts

Two or three years prior to menarche, female’s mammary gland visible enlarges

U/S shows a homogeneous tissue of moderate echogenity

Breast parenchyma appears as a small island of retroareolar tissue




Mature Breast






With the beginning of female puberty, release

of estrogen (ductal development), at first alone, and

then in combination with progesterone (lobulo-

alveolar development) when the ovaries functionally

mature, cause the breasts to undergo changes

which culminate in the fully mature form

Glands enlarge, fat and connective tissues

proliferate

Pubertal breast development is divided into five phases called Tanner Stages

This process on average takes 3 to 4 years and is usually

complete by age 16 to 20 years

The adolescent breast consists almost entirely of glandular

tissue with very little fat

6-year-old girl: small area of ill-defined echogenic tissue in the

retroareolar region

13-year-old girl: echogenic nodule with a retroareolar, stellate,

hypoechoic focus

13-year-old girl: more echogenic, glandular tissue with a

central spider-shaped hypoechoic focus

16-year-old girl: more echogenic fibroglandular tissue with a

central hypoechoic nodule. Also increased subcutaneous fat

anterior to the glandular tissue

16-year-old girl: echogenic fibroglandular tissue without a

central hypoechoic focus

Suprammamary fascia strongly

echogenic

Subcutaneous & retromammary

layers of fat are quite narrow

Glandular tissue is relatively

hypoechoic (sometimes appears

as a hypoechoic nodule)

Cysts can develop at an early age due to incomplete development of the terminal ductules

The excessive proliferation of intralobular connective tissue can lead to the development of

fibroadenomas

Very difficult to evaluate radiographically U/S is the preffered modality for investigation




Mature Breast






The fully developed human breasts lie on

the anterior chest wall atop the pectoralis

major muscle

It extends from about the second rib to

seventh bilaterally

Is composed of adipose (30%), glandular

(10-35%) & fibrous-connective (50%) tissues

Each breast consists of ~ 20 secretory

tissue lobes

The glandular apparatus is

composed of a branching system of

ducts, organized in radial pattern

spreading outward and downward

Subareolar ducts widen to form

lactiferous sinuses which exit through

10-15 orifices on the nipple

The ducts end blindl in clusters of

spaces called acini (milk forming glands)

An important anatomical space

called the retromammary space lies

between the pectoralis muscle and

the breast. The space is filled with a

layer of fat tissue

Projecting through this fat layer is

a deep fascia that extends into the

pectoralis muscle. This network of

connective tissue fascia (suspensory

ligaments of Cooper) gives shape

and support to the breast

parenchyma.

Each month the epithelium and

stroma undergo cyclic stimulation

The breast increases in size,

tenderness, firmness and blood

supply

Ducts enlarge with an increase

in the number of cells lining the ducts

and the breast retains more fluid

The breasts are least engorged

7-10 days after the beginning of

menses Hormones affecting the breast

Normal skin appears as a white

line of 3mm or less

Significant individual variations

can occur both in the relatively

proportion of hyperechoic glandular

tissue and in the more hypoechoic

fatty tissue

Skin (1-3mm)

Subcutaneous fat transeversed

by Cooper ligaments & superficial

fascia (dark layer criss-crossed by

bright lines that extend to the skin and

hyperechoic band separating the fat

from the mammary gland)

fibroglandular tissue + lactiferous ducts

Breast parenchyma (sponge with

large pores–lobules which are clearly

distinguisable from the surrounding

breast tissue

Interlobular connective tissue-white

lines

Lactiferous ducts as tubular

hypoechoic structures

Deep fascia –thin echogenic band

Retromammary fat hypoechoic

Pectoralis major muscle fascia

(hypoechoic layer with an internal pattern

of parallel linear echoes)

Rib surface-broad, convex, echogenic

stripe with posterior acoustic shadowing

Mature Breast 1st half

Mature Breast 2nd half

Mature Breast

Mature Breast (Dense Breasts)

Premenopausal Breast

Premenopausal Breast (exam day)

Occasionally, a milky or patchy diffuse enhancement, sometimes focal

enchancement, can appear in normal glandular tissue before and after

menstruation.

Examination is recommended between day 6 and 12 of the menstrual cycle

Normal Breast - Gd Enhancement Kinetics

Very Dense Breast

Mature Breast 1st half




Mature Breast






First trimester:

Proliferating glandular epithelium causes branching of the ducts

Amount of fat and connective tissue decreases

• Decreased echogenicity of breast tissue

• Echo pattern appears finely glandular

Second trimester:

Alveolar epithelium differentiates into a secretory epithelium

Arborization of the alveoli causes enlargement of the breast

Colloid accumulates in the alveoli

Distended lactiferous ducts are discernible as tubular

extremely hypoechoic or anechoic structures

Third trimester:

Differentiation of the milk-producing cells and synthesis of milk.

In the last days before delivery, increase of blood flow in the breast and filling of the alveoli

and ducts with colostrum

Young pregnant woman: dilated anechoic ducts seen in cross section

deep to the areola

Adenosis of Pregnancy Diminution of fibrous stroma

Formation of new acini or lobules

Cysts, fibroadenomas and

other benign breast change can develop or if already

existing may be enlarged




Mature Breast






Immediate post partum enlargement

due to colostrum accumulation

Milk secreted into alveoli 3 - 7 days post

partum

Breastfeeding stimulates prolactin

Ductal structures (notably central) are

dilated

Fat content of breast decreases

(subcutaneous fat layer is thinned)

+

+

Strong generalized contrast enhancement (increased vascular

permeability) is expected in the engorged breast

There is generalized parenchymal involution,

with variable degree

Periductal and perivascular stromal tissue

increases

Alveolar cells and ductal branches regress

2 months after Pregnancy (no lactation)




Mature Breast






The majority of breasts cancers occur at this age

Glandural tissue atrophies, connective tissue becomes less cellular and the amount

of collagen decreases

The breast initially increases in fatty tissue (perimenopausal), then decreases in

glandular tissue (post-menopausal) and decreases in firmness.

: fat 20%, fibrous 60%, glandular 10-35%

: fat 40%, fibrous 55%, glandular 5-20%

(35% of women pattern of reproductive age)

: fat 50%, fibrous 50%, glandular <10%

: the breast parenchyma has disappeared completely in 71% of women,having

been replaced by fat

Islands of residual parenchyma are clearly

visible as small, hypoechoic “pores” within the

dense, hyperechoic connective tissue

Cooper ligaments are thickened

Development of small retention-type cysts

may be seen due hormonal alterations

Central dilatations of the main ducts (up to

10mm) are commonly seen

Involution of the mammary lobules

progresses rapidly and can be classified

as: lipofibromatus (predominately fat) or fibrolipomatus

Postmenopausal Breast

Fatty tissue has a high signal intensity

Residual parenchyma and connective-tissue structures have low signal intensity

Fatty Breast

Old Woman Heart Failure

Patients on long-term immunosuppresing corticoid

therapy show complete lipomatous breast involution

after taking the medication for many years




Mature Breast






Hormone replacement delays involutional changes in the breast

Generalized increase in the extend and density of partially involuted parenchyma

Selective Estrogen Receptor Modulator - SERMs

Age-Related Changes of the Breast in US and MR

Health & Medicine

Transcript of Age-Related Changes of the Breast in US and MR