Anatomic & Physiologic ConsiderationsBy

Dr. Dorria Salem, Professor of Radiodiagnosis, Cairo University-------------------------------------------------------------------------------------

Anatomy• The breast is a modified skin gland. It develops on the chest wall between the

clavicle and the 6th-8th ribs.• Breast tissue can be found as far medially as the sternum and laterally to the

midaxillary line.-------------------------------------------------------------------------------------------------------Skin

• The skin of the breast is 0.5-2mm.thick. Just beneath the skin lies,the superficial fascia that at the level of the breast divides into superficial &deep layers. The breast develops between the split layer of fascia and is enveloped by it.

• The deep layers of this split fascia forms the retromammary fascia; and this lies immediately on the fascia that overlies the pectoralis.major.muscle (prepectoral fascia)

• providing a surface that permit some movement of breast on the chest wall.• BVs + lymphatics penetrate the fascial layers, coursing between the muscle&

the breast

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Subcutaneous fat• Immediately beneath the skin is the subcutaneous fat. This layer varies with

individuals. In some females it is clearly separate from the parenchymal cone of the breast. In others it cannot be distinguished from fat between the glandular structures.

-------------------------------------------------------------------------------------------------------AreolaThe pigmented tissues of the areola contain numerous sweat and sebacous glands. The skin of the areola is thicker than the rest of the breast skin; tapering down towards the limbus of the areola. The small raised nodular structures that are distributed over the areola are Morgagni’s tubercles and define the openings of Montgomery’s (sebacous) glands.-------------------------------------------------------------------------------------------------------NippleThere are between 8-20 major ducts that open on the nipple. The width of each duct is 0.5-2mm The ducts and its tributaries defines a lobe of the Breast. Beneath the nipple openings; the major ducts dilate into their ampullary portions (lactiferous sinuses).The deeper segmental ducts divide into subsegmental structures& may branch further until they form the terminal duct that enters the lobule. A terminal duct & its lobule are called “terminal duct lobular unit” TDLU. This can also be found as immediate branches of the major ducts and are not always at the periphery.

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Blood supply

Arterial supply:• Medial: internal mammary artery• Lateral: axillary artery

lateral thoracic thoracodorsal intercostalsVenous drainage:

• Internal mammary v: direct communication with pulmonary capillary bed, providing major routes for hematogenous metastases

• Axillary vein • Intercostal vein: direct communication

-------------------------------------------------------------------------------------------------------Lymphatic drainage

• Drainage from deeper tissues of the breast Ù surface Ù skin subareolar plexus Ù axilla

• Small % : drain to upper abdomen medially to internal mammary lymphatics

-------------------------------------------------------------------------------------------------------Supporting Structures

• The single layer of fascia that lies beneath the skin divides into deep and superficial layers that form an envelope within which the breast develops.

• The breast is given structure by the fibrous tissues that surround and course through it.

• The stromal, epithelial and glandular elements of the breast are held together by an interlacing network of fibrous CT.

• This supporting network forms planar sheets of fibrous tissue that course between the deep and superficial layers of fascia, incompletely compartmentalizing the structures of the breast= cooper’s ligament.

-------------------------------------------------------------------------------------------------------The Normal Breast:Menstrual Variation, Lactation and Aging -------------------------------------------------------------------------------------------------------Imaging of the breast is further complicated by physiologic changes that occur in relationship to the patient’s age and stage in the menstrual cycle. The breast in young women is extremely dense and consists mostly of glandular tissue. In lactation, the glandular tissue is more dense.

In later part of menstrual cycle, the glandular tissue increases in density and size: As a woman ages, the glandular tissue is slowly replaced by fat-------------------------------------------------------------------------------------------------------

Radiography of the Breast

1)Molybdenum anode:• Low energy photons in 15-20 Kev range

2)FiltersNeeded are “molybdenum filters” to filter high energy photons “undesirable photons”3)Compression 1- Making the thickness of the breast more uniform: to avoid underexposing the base & overexposing the thinner anterior tissues.2- Decreased geometric sharpness.3- Increased resolution.: Because the closer an object to the film, the smaller the penumbra+ the sharper the image4) ScreenRare earth Ù Green light e.g. lanthanum, gd oxysulphideÙ Blue light recentlyMammography uses a single-sided radiographic intensifying screen approximately matched to a single-emulsion film.The speeds of these systems are 15-30x faster than the direct exposure filmsThese higher speeds result in a substantial reduction in the radiation dose but with a small sacrifice in resolution5)Film (single emulsion) Ùgel ÙcrystalsConsists of a clear or colored-tinged (dyed) backing material coated on one side with a gel containing uniform distribution of silver halide crystals.6)Film/Screen combinationThe emulsion side of the film is placed in direct contact with the phosphorus layer of the screen.7)Film developingIs a process that amplifies the chemical changes that are present in the latent image by converting the other silver ions in the grain to metallic silver that is black making the image visible.8)Automatic Exposure control AECVIPÙ to decrease under & over exposure.These are sensors that lie under film cassette.They measure the radiation that passes through the breast and cassette. They are calibrated such that when sufficient X-ray photons have reached the AEC, the exposure is terminated, & the film is thus properly exposed.9)Dose/ ImageAbsorbed mid breast dose is 0.1 – 1 rad/2 film examinations10)MarkersMarkers are placed in the axillary portion of the images

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Positioning1. Craniocaudal (CC)2. Mediolateral (ML)3. Mediolateral Oblique (MLO)4. Additional views:a) Cone down compression

b) Magnified viewc) The breasts should be considered symmetrical organs.d) Position the mammogram as mirror images

----------------------------------------------------------------------------------------------------Breast Ultrasonography

• Breast ultrasonography is an important, first diagnostic imaging modality that is complementary with mammography. It should not be used for screening for any age group, but when properly employed it can increase the overall diagnostic accuracy of breast imaging.

• The important role of ultrasound is the differentiation of a cyst from a solid mass. In this role, its accuracy is in the range of 96% to 100%

• US should be performed with 7.5-10 MHZ real time system.• US has been recommended as the primary imaging technique for wome <

30yrs. with breast problems, this is because:1. Lower prevalence of breast Ca2. The breast , will be dense and poorly identified by mammography.3. Susceptibility to radiation induced malignancy

-------------------------------------------------------------------------------------------------------Indications

• Differentiation of cysts from solid masses• Evaluation of a palpable mass not visible in radiographically opaque breast• Evaluation of palpable mass in young patient• Evaluation of an inflammed breast for the presence of an abscess• Evaluation of a mass that cannot be completely evaluated by mammography

because of its deep location• Guidance for interventional procedures• For duplex color flow

------------------------------------------------------------------------------------------------------- Benign lesion are usually sharply circumscribed where as malignant lesions are usually irregular in shape• A cyst should have no internal echoes even at high gain.• The solid lesion may have distal enhancement. Although such solid lesions are

usually benign, cancer can do this as well.• U.S. has been suggested as the initial imaging modality of choice in the young

(less than 30yrs of age) patient with palpable mass. If a cyst or a solid mass cannot be identified, then a single view mammogram can be performed to detect possible microcalcifications.

• It Is important to note that ultrasonography will not identify all solid masses, especially in a fatty background except for a cyst.

• The use of doppler U.S. and color doppler may improve cancer detection by demonstration of increased blood flow.

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Benign lesions of the Breast

Dr. Dorria SalemProfessor of Radiodiagnosis,

Cairo University-------------------------------------------------------------------------------------------------------Benign lesions of the Breast

--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Benign lesions of the Breast:A.Ducts 1) Papilloma Benign proliferation of ductal epithelium that projects into lumen of the duct& is connected to the epithelium by a fibrovascular stalk. Within major ducts= subareolar in location. Usually single, when multiple they occur in peripheral ducts. They extend longitudinally in the duct lumen. The duct around it can dilate forming a cyst.( Origin of “intracystic papilloma”).

• Presentation: serous or bloody nipple discharge ( due to their fragile blood supply leading to necrosis, infarction and bleeding).

• Mammogram: - usually Ù invisible - rarelyÙ retroareolar mass - sometimes Ù subareolar microcalcification clusters lucent centered calcification

Galactography: filling defect U/S: solid, hypoechoic, usually lobulated masses within cystically dilated

ducts. N.B. papillomatosis = epithelial hyperplasia

Benign

A.Ductal B.Stromal C.Lobular

PapillomaDuct ectasia Plasma cell mastitis (Secretory deposits)4. Galactocele

LipomaScarring&fat necrosisHamartomaRadial scarAbscess

FibroadenomaCystsMammary dysplasia

2)Duct ectasia 1ry affects the major ducts in the subareolar region. The distended ducts are filled with fluid or thick unresorbed secretions and

cellular debris. Etiology: 2ry to periductal inflammation. The duct may be weakened by surrounding inflammation become

patulous, filled with unresorbed debris which may calcify. Mammogram: Tubular, serpentine structures converging to the nipple in

the subareolar region U/S: anechoic fluid filled tubular structures. With debris

3)Secretory deposits = Plasma cell mastitis These appear in one of these patterns. a) thick continuous solid, rod-shaped deposits oriented along duct lines diffusely or segmental distributionb) Lucent centre rod-shaped calcificationc) Lucent centered globular calcification

They are called plasma cell mastitis because of the plasma cell infiltrate that are histologically part of the inflammatory process.

D.D. Ca calcification4)Galactocele

Occasionally a milk containing cystic structure develops during lactation or in the months after the cessation of nursing.

Age: 20’s-30’s Etiology: Obstruction of a duct . The proximal (lobular) segment becomes distended with inspissated milk. Clinically: it is indistinguishable from other causes of a rounded mass. Mammogram: if the milk filled cystic mass has enough fat content Ü well

circumscribed radiolucent mass.----------------------------------------------------------------------------------------------------Benign lesions of the Breast:B.Stromal1)Lipoma

They are generally superficial, around the periphery of breast parenchyma. Encapsulated. Freely movable. Displace normal structures. Mammogram: radiolucent, well capsulated lesion displacing the normal

breast parenchyma U/S: hypoechoic similar in echotexture to subcutaneous fat but

distinguished from it by the capsule.

2)Fat necrosis Etiology: a nonsuppurative inflammatory response to fat cell damage 2ry to

trauma or surgery. Clinically: palpable (sometimes painful) mass with associated skin thickening

or retraction. It most commonly develops unoticed by the patient.

D.D. Ca

Mammogram: New density with spiculated outline. Architectural distortion Ca+ deposition Oil cyst

3)Hamartoma = (Fibroadenolipoma) Proliferation of fibrous and adenomatous elements in fat surrounded by a

capsule of connective tissue.

4)Radial Scar Benign lesion. Grossly: with a chalky appearance that is similar to cancer, and connective

tissue spicules radiating from a central nidus.

Histologically: The nidus is predominantly elastic tissue mixed with fibrosis. The surrounding ducts are distorted& there is frequent adenosis and epithelial proliferation. They may contain microcalcification which likely arise in the associated adenosis.

Mammogram: Spiculated lesion

5)Abscess Organism: staphylococcus, introduced through a skin crack around the

nipple/areola complex usually associated with breast feeding. Mammogram: Nonspecefic Skin thickening U/S: hypoechoic mass with illdefined margins & internal echoes.

---------------------------------------------------------------------------------------------------Benign lesions of the Breast:C.Lobular

1)Fibroadenoma Most common benign solid lesion of the breast. Age: early in life starting teenage to 30’s Pathology: overgrowth of the specialized stromal connective tissue of the

lobule. Pathology: overgrowth of the specialized stromal connective tissue of the

lobule. Its enlargement causes elongation &stretching of the acini. The acini+interlobular terminal ducts are surrounded and compressed by this

idiopathic proliferation of collagen within the lobule Size: range from microscopic to >10cm = giant fibroadenomas. Involution: calcification (due to hyalinization) = popcorn calcification Mammogram: sharply circumscribed, well defined, rounded or oval smoothly

lobulated. May be surrounded by a lucent halo = optical illusion May have flattened contour D.D. cysts. Calcification

Giant fibroadenoma U/S: Ovoid= longer than deep. Sharply defined margins. Fairly uniform internal echoes.

2)Cysts Age: 30-50yrs Pathology: as the lobular epithelium atrophies, the acini coalesce, producing fluid-

filled spaces surrounded by the sclerotic specialized connective tissue of the lobule.

some cysts are actually distended large ducts. Mammogram: Single or multiple Rounded or ovoid, well defined. Surrounding halo. May disappear on follow up Ù resorbed Ù decrease in size Eggshell-thin rim of calcification. U/S: rounded or oval sharply defined margins. No internal echoes. Bright posterior acoustic enhancement.

3) Mammary Dysplasia Definition: Benign proliferation of breast stroma.Types: a)cystic form: when lactiferous ducts consist of cystic dilatation of varying size.b)Fibrous form when changes are predominantly periductal fibrosis.c) Adenosis form: enlargement of the lobule 2ry to a benign proliferation of the acini. This proliferation within the TDLU is 1ry an elongation and multiplication of

the acini accompanied by an overgrowth of the epithelial &myoepithelial and connective tissue elements in the lobule.

cystic dilatation of the acini is where Ca+ ppt. (D.D. Ca)

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Malignant Lesions of the BreastDr. Dorria Salem,

Professor of Radiodiagnosis,Cairo University

-------------------------------------------------------------------------------------------------------Malignant Lesions of the Breast

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Malignant

Primary Secondary

Ductal Stromal Lobular

Malignant

Primary Secondary

Ductal Stromal Lobular

DCIS= Poorly differentiated =comedo ca Moderately well diff.=large cell Well diff.=small cell, micropapillary, cribriformInvasive=NOS (scirrhous)Paget’s diseaseTubular Ca=attempts to form ductsColloid Ca= increased mucinMedullary= Syncytial growthInflammatory Ca= early dermal lymphatic invasion

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------------------------------------------------------------------------------------------------------Malignant lesions: A.Ducts1) DCIS:Poorly differentiated Comedo Ca

Definition: Comedo Ca is merely gross descriptive terminology for a duct Ca that is characterized by abundant cells that fill the ducts of the involved lobe with frequent areas of necrosis that often calcify.

When cut in cross-section, this necrotic debris is extruded from the duct like a comedo.

As other ductal Ca, it may be confined to the ducts or associated with varying degrees of invasion.

The lesion is usually detected by its classical microcalcification on mammography.

-------------------------------------------------------------------------------------------------------Malignant lesions: A.Ducts2) Invasive Duct Ca “NOS”=Scirrhous

When a Ca does not fit into any of the defined subtypes it is termed “NOS”. It accounts for 65% of the breast Ca diagnosed in USA. It elicits a fairly vigorous desmoplastic response with cicatrization and

fibrosis. This produces a very hard mass on palpation. And a gritty texture on cut section.

-------------------------------------------------------------------------------------------------------Malignant lesions: A.Ducts4) Medullary Ca

Round or lobulated. Relatively soft on physical examination. Fairly movable in the breast, therefore they do not infiltrate aggressively. They grow quite large before being detected

------------------------------------------------------------------------------------------------------Malignant lesions: A.Ducts5) Inflammatory Ca

Clinically: Red, hot, peau d’orange thick skin. May respond to antibiotic therapy making the diagnosis more difficult. Age:30yrs (usually old age) Histologically:

Early invasion of dermal lymphatics by aggressive form of infiltrating Ca. The underlying 1ry lesion is frequently not evident. Poor prognosis, worse than an infiltrating duct Ca Ù diffuse trabecular

thickening and overall increased density, that has 2ry invaded the skin.-------------------------------------------------------------------------------------------------Malignant lesions: B.Stromal Phylloide’s tumour

This term is due to its leafy pattern of growth. Most are benign, but about 25% will recur locally if treated incompletely&

10% metastasize. It is classified among sarcoma as it metastasizes hematogenously to the lung

as does sarcoma and not to axillary L.N. as Ca. Shows rapid growth over months. Age:30-50yrs Although sharply defined, it does not have a capsule. It arises as does fibroadenoma, from the specialized CT of the lobule.

-----------------------------------------------------------------------------------------------------Malignant lesions: B.Stromal Phylloide’s tumourMammogram:

well defined, with no spiculations or microcalcifications. Nothing could differentiate between benign and malignant forms.

U/S Similar to fibroadenoma

-------------------------------------------------------------------------------------------------------Malignant lesions: C.Metastases

a) osteogenic sarcomab) Lymphoma

(i)localized (ii) diffuse (iii) 1ry------------------------------------------------------------------------------------------------------

Fundamental signs that suggest Excisional Biopsy1)Microcalcifications:

The search for breast microcalcifications is one of the essential elements in the interpretation of mammograms.

30% - 50% of occult Ca present by isolated microcalcifications.2)Rounded opacities that are clinically occult:

These represent 10 to 20% of clinically occult cancers, although they are easy to see in fatty breast, they are extremely difficult to identify in a dense, nodular breast.

Sonography is of a great importance in the identification and characterization of these rounded opacities.

3)Spiculated opacities that are clinically occult: The spiculated density represents 20% to 30% of clinically occult cancers. These lesions are highly suspicious for malignancy. Once the reality of these

images is confirmed by its presence on several projections, then excisional biopsy must be performed.

4)Architectural Distortion: Architectural distortion are different from microcalcifications which are

relatively easy to see and difficult to characterize. The focal architectural distortion is difficult to identify, after eliminated

previous biopsy scarring, fat necrosis or abscesses. The most common etiology (greater than 50%) of focal parenchymal distortion

is breast cancer.

sign %

Architectural distortion

>50

Microcalcifications 30-50

Spiculated opacities 20-30

Rounded opacities 10-20

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