Benign vs. Malignant
Compressibility testing
• Ability of a mass to deform with manual or transducer pressure
What is skin thickening?
• Can be focal or diffuse • Thickened dermal tissue is more echogenic than normal • Interruption of the dermal layer is a suspicious finding
Other calcifications characteristics
• Cannot routinely detect clustered microcalcifications • Calcifications are hyperechoic and may occur in benign and malignant processes • Intramammary calcifications originate in the ducts or lobules • Vascular calcifications are occasionally seen • Microcalcifications are difficult to visualize sonographically unless contained within a hypoechoic mass • These tiny hypoechoic foci do not cause shadowing because they are smaller than the width of the sound beam
What does Sharpness mean?
• Clarity of margin delineation
Vascular characteristic
• Distribution and number of peripheral and intratumoral vessels • Power doppler is typically more sensitive to blood flow because of its high sensitivity to slow flow and lack of angle dependency • Spectral Doppler allows measurements of velocities, pulsatility and resistive indices • Doppler assessment of tumor vascularity requires settings that are optimized for low flow states and the use of minimum transducer pressure • A reduction or cessation of blood flow can occur if too much transducer pressure is applied over the mass • Presence of blood flow in a mass confirms that it is solid
What is effects on distal echoes?
• Intensity of the echoes posterior to the mass depends on the degree of sound beam attenuation, compared to adjacent tissues at the same depth
What does shape and orientation mean?
• Overall contour of a mass and the position of the mass in relation to the chest wall or the skin
What does echogenicity mean?
• Relative brightness of echoes within the mass or tissue • Compared to that of adjacent normal fat • Depends on tumor type, composition and growth pattern • Not highly sensitive, overlap in findings
What does Contour mean?
• Surface characteristics and external shape of margins
What does echo texture mean?
• Uniformity of echo distribution within a mass or tissue • Depends on tumor type, internal composition and on the degree of tumor degeneration, necrosis and calcific change
Secondary features
The effects of the mass on surrounding tissues or changes in the tissues in response to the mass
What does Border Thickness and Echogenicity mean?
Thickness and echogenicity of the tissue around the mass
Malignant effects on distal echoes
o Acoustic shadowing associated with a mass or focal area of architectural distortion o May emanate from all or part of a mass, be of variable intensity and obscure portions of the posterior wall o Often seen with invasive cancers with prominent fibrous stromal tissue o The amount of fibroelastic host response (reactive fibrosis, desmoplasia) can affect the degree of shadowing o Slow growing, low-grade invasive ductal carcinoma and tubular carcinoma often display intense shadowing o A high percentage of cancers do not display any significant shadowing o Highly cellular cancers such as colloid, medullary, papillary and some necrotic, infiltrating ductal carcinomas may display enhancement o Higher grade, relatively circumscribed cancers that contain lots of tumor cells, lymphocytes, plasma cells, and vascularity tend to display enhancement
Malignant vascularity
o Associated with the development of new blood vessels o These vessels lack a muscular layer and are prone to A-V shunting o Cancers tend to display more peripheral, penetrating and internal blood vessels as compared to benign solid masses o Spectral Doppler of cancers tend to display higher peak systolic velocities than benign masses o Conventional Doppler techniques cannot detect blood flow in all cancers, therefore lack of flow does not exclude malignancy o Light transducer pressure is necessary when performing a Doppler examination to avoid ablation of small blood vessels
malignant calcifications
o Clustered microcalcifications (> 5 per cubic cm) o May be linear distribution o Best seen by mammography o Common features of DCIS o When seen with invasive lesions, microcalcifications usually correlate with intraductal components of the tumor o Linear branching is a common feature of comedocarcinoma o Widespread distribution may be associated with extensive breast cancer o Tiny non-shadowing punctate calcifications within a mass are more likely to be malignant than benign
Benign features on ducts
o Duct dilatation/ectasia can be associated with pregnancy and lactation, mastitis, peri and postmenopausal changes, fibrocystic change or distention from an internal benign mass o Echoes within or along a duct wall can be generated from proliferative changes, papilloma, papillomatosis or from benign ductal microcalcifications, inspissated fluid, blood, pus, or milky secretions o Should be correlated with any history of nipple discharge
Malignant features on ducts
o Duct invasion or the presence of intraductal (in situ) cancer can cause localized duct dilatation, intraductal echoes, irregularity, thickening and nodularity of the duct walls o Microcalcifications may be seen o Papillary carcinoma can generate mass effect as well as cause bloody nipple discharge
Benign vascularity
o Fluid -filled structures lack internal vascularity and do not display internal Doppler signals o Remember that moving particles within a complex cyst can cause color when in color or power mode - Spectral Doppler confirms that this is artifact and is not related to blood flow o With conventional Doppler, benign solid masses usually lack a flow signal or are hypovascular o Lymph nodes demonstrate hilar blood flow o Inflammatory processes display hypervascularity
Malignant echo texture
o Heterogenous echopattern o Highly cellular cancers may display relatively homogenous internal echoes
Benign lymph nodes
o Intramammary lymph nodes are small (<1 cm) and more often seen on US in the UOQ of the breast o May mimic a solid breast lesion o A normal lymph node has an oval, reniform shape, a hypoechoic outer cortex and a central echogenic fatty hilum o Benign reactive adenopathy occurs in response to infection, immune disorders, fibrocystic change and other conditions o Palpable nodes may be tender o Reactive lymph nodes show symmetric enlargement , but retain their reniform shape and maintain an echogenic hilus
Malignant causes of skin thickening?
o Invasive breast cancer, especially inflammatory carcinoma o Lymphatic obstruction from malignant disease o Metastatic breast carcinoma from the opposite breast o Lymphoma o Advanced gynecologic malignancies from thoracoepigastric collaterals
Malignant effects on fibrous planes
o Invasive breast cancers infiltrate surrounding tissues as they grow and can cause secondary features such as architectural distortion, focal disruption of fascial planes, and thicknening and retraction of Cooper's ligaments o Disruption of the superficial fascial plane allows malignant spread to the subcutaneous layer and skin o Superficial fat may become echogenic o Superficial extension can cause interruption of the dermal layer, skin thickening and retraction or nipple retraction o Deep tumors may grow into the pectoral fascia and musculature
Malignant Compressibility testing
o Invasive ductal cancers are typically non-compressible with transducer pressure because of the amount of fibrous tissue they contain o Acoustic shadowing from scirrhous-type invasive carcinomas with reactive fibrosis cannot be obliterated with transducer pressure o Transducer pressure can assess fixation of an invasive mass to adjacent tissues
Angular Contour Characteristics
o Irregular jagged margins o Highly sensitive and specific for malignancy o Occur where resistance to invasion is lowest
Malignant shape and orientation characteristics
o Irregular shape is common o Vertical orientation is suspcious o Longest axis of the mass is perpendicular to the chest wall or skin o The anteroposterior (AP) dimension is greater than its sagittal or transverse dimension, "taller than wide" o "Taller than wide" feature is typical of small cancers (less than 1 cm) that primarily affect a single lobule o Vertical orientation is associated with incompressible cancers that have invasive growth patterns with infiltration into surrounding tissues o Larger cancers or circumscribed lesions may be more ellipsoid or round
Malignant echogencity characteristics
o Marked hypoechogenicity of a solid mass o Some cancers may be mildly hypoechoic or isoechoic to fat
Mircolobulation
o Multiple small lobulations on the surface of the mass o Correlates with mammographic microlobulation and may represent - fingers of invasive tumor, intraductal components, enlarged cancerous lobules o Malignant feature
Malignant Sharpness Characteristics
o Non-circumscribed or ill-defined margins o Indistinct margins indicate invasion into adjacent tissues or host response to the tumor
Intraductal tumor extension
o Projection from the surface of the mass that extends within a duct leading toward the nipple o Projections that branch outward from the mass within the ducts extending away from the nipple o Best seen with radial and antiradial scanning o Measurements should include intraductal extensions
Benign shape and orientation characteristics
o Round shapes are seen with tense cysts and some small, solid masses o Oval (ellipsoid, elliptical) shape is typical of most benign masses and larger non-tense cysts and fluid collections o Some masses may show lobulation o Orientation is typically horizontal with the longest axis aligned parallel to the chest wall or skin o Dimensions of the mass are "wider than tall" o Horizontal orientation indicates growth within tissues planes rather than across tissue planes
Benign effects on distal echoes
o Simple cysts are non-attenuative and demonstrate enhanced distal sound transmission (acoustic enhancement) o Solid masses tend to display minimal or no distal sound enhancement o Some benign masses may display shadowing such as hyalinized or calcified fibroadenoma, fat necrosis, radial scar, granular cell tumor or focal fibrosis
Benign Contour Characteristics
o Smooth margins o Mild lobulation (macrolobulation): the presence of three or less gentle macrolobulations
Benign effects on fibrous planes
o Solid and cystic masses displace or compress adjacent tissues as they grow o Larger masses can displace Cooper's ligaments and fascial planes o Do not interrupt or grow across tissue planes o Some benign processes that may disrupt tissue planes include inflammatory, post-radiation or traumatic processes
Benign Compressibility testing
o Some degree of compressibiilty is common with non-tense cysts and fluid collections, fat lobules, lipomas, and hamartomas o Transducer pressure may also be used to eliminate artifactual shadowing and to assess mass mobility
Malignant Contour Characteristics
o Spiculated margins o Feature most specific for invasion o Appear as alternating hyperechoic and hypoechoic straight lines that radiate perpendicularly from the surface of the mass o Echogenic halo around suspicious mass may represent unresolved spiculations o Measurements should include spiculations
Malignant Thickness and echogenicity characteristics
o Thick, echogenic halo around a solid mass can indicate tumor infiltration or host response o Peritumoral lymphedema can increase the echogenicity around a mass o Posterior features may be obscured by the lesion or by shadowing from the lesion o Hyperechoic rim is best seen when adjacent to fat and may be difficult to see if surrounded by echogenic fibroglandular tissue o Echogenic halo has been shown to be associated with unresolved spiculations and should be included in the overall measurement o Newer high frequency transducers are able to resolve this spiculations
Benign Thickness and echogenicity Characteristics
o Thin, echogenic pseudocapsule o Compress, rather than invade, adjacent tissues as they grow o is best seen along the side closest to the transducer when the mass lies adjacent to fat o Scanning with variable pressure and beam angulation (heel toe technique) demonstrates completeness of the capsule
Benign causes of skin thickening?
o Trauma, bruising o Acute mastitis, abscess o Radiation therapy o Reduction mammoplasty o Dermatologic - scar o Right heart failure o Nephrotic syndrome
benign calcifications
o Typically course and large enough (macrocalcification) to cause distal acoustic shadowing o "Popcorn-like" calcifications are a feature of older fibroadenomas o Calcification can form secondary to necrosis, hemorrhage or scarring o Curvilinear rim calcification can be a benign complication of sebaceous cysts, oil and hemorrhagic cysts and older fibroadenomas o The sediment of a milk of calcium cyst has a "tea-cup" appearance mammographically o Ductal and/or parenchymal calcifications are associated with secretory disorders or fibrocystic changes
Malignant lymph nodes
o Typically enlarged and attain a more rounded, bulky, lobulated or irregular shape o The echogenic hilum of a malignant node is either displaced or absent depending on the degree of hilar invasion o Once the hilum is invaded, the node displays a hypoechoic homogenous to heterogenous appearance o The outer margins stay smooth and circumscribed unless there is capsular extension o The axilla is the most common sire for lymph node metastases
Benign echo texture
o Typically homogenous, uniform distribution and intensity of internal echoes o Larger masses may be heterogenous with non-uniform distribution and intensity of echoes due to internal fibrosis, degeneration or calcification
Benign echogencity characteristics
o Uniform marked hyperechogenicity typically indicates benign stromal fibrous tissue o A discrete, echogenic lesion is the subcutaneous fat may indicate lipoma o Low to medium level internal echoes (isoechoic ro mildly hypoechoic compared to fat) usually indicates benign solid tumor o Simple cysts are anechoic
Benign Sharpness Characteristics
o Well-defined, circumscribed margins show an abrupt transition between the mass and the surrounding tissues o Well-circumscribed margins indicate the mass is displacing, rather than invading, surrounding tissues as it grows
