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Flashcards in BREAST Deck (18)
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1
Q

BENIGN LESIONS WITH TYPICAL

IMAGING APPEARANCES

A
  1. Fibroadenoma—involuting fibroadenomas may contain typical
    ‘popcorn’ calcification on mammography, which precludes the
    need for further imaging or biopsy. In the UK national guidance
    recommends that biopsy in women <25 years is not necessary for
    confirmation if typical features of a fibroadenoma are present
    (well-defined, ovoid/round, up to three gentle lobulations). Other
    countries follow BIRADS recommendations, which advocate US
    follow-up.
  2. Intramammary lymph node—most often in the upper outer
    quadrant. A fatty hilum is a characteristic feature, typically seen in
    normal and reactive lymph nodes, but may also be present in
    pathological nodes—this is seen as a focal radiolucency within
    the node on mammography (may be difficult to appreciate),
    fat signal on MRI or hyperechoic on US. Normal or reactive
    nodes often have ‘suspicious’ enhancement characteristics
    on MRI.
  3. Lipoma—well-defined, rounded, exclusively fat-containing.
  4. Oil cyst—well-defined, lucent on mammography ± ‘egg-shell’
    peripheral calcification. The presence of multiple subcutaneous oil
    cysts is characteristic for steatocystoma multiplex (many other
    subcutaneous oil cysts will also be present on the trunk).
  5. Hamartoma—‘breast tissue within breast tissue’ or ‘salami-slice’
    appearance on imaging due to variable mix of fatty and glandular
    tissue
2
Q

SINGLE WELL-DEFINED MAMMOGRAPHIC
SOFT-TISSUE OPACITY
Benign

A
  1. Cyst—round/oval, low-density mass. In the case of an oil cyst: rounded, fat density mass ± peripheral calcification.
  2. Fibroadenoma—round/oval mass, similar density to glandular breast parenchyma. Cysts and fibroadenomas can have similar appearances on mammography.
  3. Intramammary lymph node—common in normal breasts.
  4. Skin lesion—e.g. irregular ‘warty’ skin papillomas. The air/soft-tissue interface creates a characteristic hypodense halo around skin lesions. Skin markers may be used to confirm.
5. Nipple not in profile—may resemble a soft-tissue opacity on the 
mediolateral oblique (MLO) view.
  1. Hamartoma—variable appearance depending on composition—if mostly glandular tissue it can present as a well-defined mass with density identical to surrounding glandular parenchyma. If mostly fatty, it can present as a well-defined lucent mass.
  2. Galactocoele—round/oval mass in a lactating woman. Appearance depends on proportion of fat, water and milk content. May mimic lipoma (if high fat content), hamartoma (if mixed viscous contents) or cyst. May contain characteristic fat-fluid level if contains fresh liquid milk. Can become infected.
  3. Sebaceous cyst—opacity related to the dermis.
  4. Lactating adenoma—occurs during lactation or in the third trimester of pregnancy. Imaging features are similar to fibroadenoma. Regresses spontaneously after cessation of breast feeding.
  5. Pseudoangiomatous stromal hyperplasia (PASH)—the rare
    tumoural form presents as a well-defined, noncalcified mass in a
    premenopausal woman. Can mimic fibroadenoma on US.
  6. Myofibroblastoma—rare benign spindle cell tumour usually found in postmenopausal women and older men. Well-defined, round/oval, noncalcified mass, hypoechoic on US, mimicking fibroadenoma (patient age can be a useful discriminator).
  7. Other rare soft-tissue masses not specific to the breast—e.g. haemangioma (± phleboliths), leiomyoma (often near areola), schwannoma, neurofibroma, solitary fibrous tumour. These are typically well-defined and hypoechoic on US (mimicking fibroadenoma), although haemangiomas may be microlobulated and have variable echogenicity.
3
Q

SINGLE WELL-DEFINED MAMMOGRAPHIC
SOFT-TISSUE OPACITY
Malignant

A
  1. Carcinoma—a small number of carcinomas can look ‘benign’ on
    mammography: high-grade invasive ductal carcinoma, mucinous
    carcinoma (often mixed solid-cystic), medullary carcinoma,
    papillary carcinoma (often within a cyst or dilated duct) and
    adenoid cystic carcinoma.
  2. Phyllodes tumour—indistinguishable from a fibroadenoma on
    mammography, but characterized by its rapid growth and often
    large by time of presentation. Usually present in an older age
    group than fibroadenomas. Most are benign, but borderline and
    malignant varieties exist. Calcification is rare. Malignant lesions
    metastasize to lung and bone, and may invade the chest wall.
  3. Metastasis to the breast—can be solitary, see Section 11.5.
  4. Lymphoma*—can appear as a single, well-defined, noncalcified
    mass. Spiculations and architectural distortion are usually absent.
    May be primary (rare) or secondary.
4
Q

MULTIPLE WELL-DEFINED
MAMMOGRAPHIC SOFT-TISSUE
OPACITIES

A
  1. Cysts—most common cause.
  2. Fibroadenomas—10-20% are multiple.
  3. Skin lesions—e.g. cutaneous papillomas, neurofibromas (NF1).
  4. Intramammary lymph nodes.
  5. Metastases—lymphoma, leukaemia (especially acute myeloid
    leukaemia), melanoma, lung and ovaries are the most common
    sources. Often involve the subcutaneous fat. Calcification is rare
    (except in ovarian cancer). Metastases elsewhere are usually also
    present.
  6. Silicone or paraffin injections—usually very dense and widely
    distributed in the breast, accompanied by dense striated appearing
    fibrosis (sclerosing lipogranulomatosis) ± dense calcification.
  7. Cowden syndrome—may present with multiple fibroadenomas,
    fatty hamartomas and/or tubular adenomas. Increased risk of
    breast cancer.
5
Q

LARGE (>5 CM) WELL-DEFINED

MAMMOGRAPHIC ABNORMALITY

A
  1. Giant cyst—radiopaque, usually low density.
  2. Giant fibroadenoma—radiopaque.
  3. Lipoma—radiolucent.
  4. Phyllodes tumour—radiopaque, indistinguishable from fibroadenoma.
  5. Hamartoma—mixed density, depending on composition of fatty
    and glandular tissue.
6
Q

BENIGN BREAST CONDITIONS THAT MIMIC MALIGNANCY

2

A
  1. Microcalcification
    (a) Sclerosing adenosis—calcification can have suspicious appearances (e.g. clustered/pleomorphic) resembling ductal carcinoma in situ (DCIS).
    (b) Amyloidosis*—can produce suspicious microcalcification.
    (c) Pseudoxanthoma elasticum—can produce microcalcifications in the breast, vessels and skin (especially in the axilla)—if all three are present this is highly suggestive of the diagnosis.
    (d) Other causes of skin calcification—e.g. chronic renal failure.
  2. Suspicious soft-tissue opacity
    (a) Summation of normal tissues—giving the impression of a suspicious abnormality on mammography. A common reason for recall after screening mammography. Small paddle compression or tomosynthesis can help separate the individual components.

(b) Fibroadenoma/cyst—when one margin appears ill-defined.

(c) Fat necrosis—typically seen after surgery, radiotherapy or trauma. Usually superficial. Ill-defined in the early stages ± a radiolucent centre. Often hyperechoic on US (a helpful feature as malignancy is usually hypoechoic). Often contains ‘malignant-appearing’ dystrophic calcification peripherally,
which progresses with time. In later stages it usually becomes well-defined, resulting in an oil cyst, but if it heals with prominent fibrosis it can mimic a spiculated mass.

(d) Postbiopsy scar.

(e) Radial scar (<1 cm)/complex sclerosing lesion (>1 cm)—
presents as a distortion on mammography or a spiculate lesion with a low density centre—‘black star’ appearance (malignancy tends to have a higher density centre). As there is a risk of associated carcinoma, these lesions are usually widely sampled with image-guided vacuum excision—there is
currently a move away from surgical excision.

(f) Haematoma—varied appearance. Usually a history of trauma, but not always. Resolves over time, but may evolve into fat necrosis or a seroma.
(g) Irregular skin lesion—e.g. wart. Look for the tell-tale hypodense halo.
(h) PASH—may have indistinct borders (Pseudoangiomatous stromal hyperplasia (PASH) is a benign mesenchymal proliferative lesion of the breast that may present clinically as a mass)

(i) Lymphocytic mastitis—ill-defined mass or masses with marked posterior acoustic shadowing on US (often more than would be expected with malignancy). Usually associated with diabetes (aka diabetic mastopathy) or autoimmune diseases such as Hashimoto thyroiditis, SLE or Sjögren’s
syndrome.

(j) Wegener’s granulomatosis, sarcoidosis and amyloidosis*—any of these can rarely produce an irregular breast mass or masses, usually in the context of widespread disease elsewhere, therefore the diagnosis may already be suspected (although biopsy is still required to exclude malignancy).
(k) Eosinophilic mastitis—very rare. Usually accompanied by peripheral eosinophilia. Can present as an ill-defined mass or an oedematous/inflamed breast.

(l) Other rare soft-tissue masses not specific to the breast—e.g. desmoid tumour (usually close to pectoral muscles), nodular fasciitis (usually located on the subcutaneous fascia), granular cell tumour (may be well- or ill-defined, usually upper inner quadrant in supraclavicular nerve territory),
inflammatory pseudotumour, Rosai-Dorfman disease. All of these appear as nonspecific, ill-defined masses indistinguishable from malignancy.

7
Q

OEDEMATOUS BREAST

Causes without erythema/inflammation

A
  1. Previous surgery/radiotherapy—common, particularly after
    axillary clearance (obstructing lymphatic drainage). Oedema is
    most pronounced 6–12 months after treatment, and gradually
    resolves, usually within 1–3 years. Malignant axillary nodes may
    also obstruct lymphatic drainage.
  2. Venous obstruction—e.g. subclavian vein occlusion.
  3. Heart failure/nephrotic syndrome—more commonly bilateral
    but can be unilateral, e.g. if patient always lies on one side
    in bed.
  4. Angioedema—rare.
8
Q

OEDEMATOUS BREAST

Causes with erythema/inflammation

A
  1. Mastitis
    (a) Acute infectious mastitis—clinical signs of infection. Most
    common in lactating women. Increased echogenicity in
    inflamed fat lobules, hypoechoic areas in glandular tissue ±
    duct ectasia. May be associated with an abscess, presenting as
    an irregular mass on mammogram and US.
    (b) Zuska’s disease—usually in nonlactating smokers. Caused by
    epithelial squamous metaplasia obstructing the lactiferous
    ducts in the nipple–areola complex, resulting in duct ectasia,
    recurrent infection, subareolar abscess formation and a
    lactiferous fistula. Surgical excision of the abscess, fistula and
    involved lactiferous duct is required for definitive treatment.
    (c) Granulomatous mastitis
    (i) Idiopathic granulomatous lobular mastitis—usually in
    young women <5 years after childbirth. Ill-defined mass
    with inflammatory change ± fistulation with skin ± axillary
    adenopathy. The mass is usually wider than tall and may
    have tubular components on US. Other causes of
    granulomatous inflammation (e.g. sarcoidosis, Wegener’s,
    TB, fungal infection) must be excluded.
    (ii) TB*—three patterns: nodular (ill-defined mass ±
    cutaneous fistulation), diffuse (breast oedema + skin
    thickening) and sclerosing (fibrosis + architectural
    distortion + reduced breast size). Axillary adenopathy is
    common and if nodal calcification is present this suggests
    TB. Breast macrocalcification may be present but
    microcalcification is rare.
    (iii) Actinomycosis—may be primary (inoculation via the
    nipple) or secondary (direct extension from intrathoracic
    disease). Primary disease presents as an ill-defined
    retroareolar mass ± cutaneous fistulation ± breast
    oedema, without calcification or adenopathy. Secondary
    syphilis (very rare) and TB can have similar appearances.
  2. Inflammatory carcinoma—can mimic mastitis. Usually a short (<3
    months) history of symptoms. Trabecular thickening and skin
    thickening on mammography. Altered echogenicity ± mass on US
    with skin thickening. Microcalcifications and axillary adenopathy
    may also be present. The inflammation is caused by the tumour
    obstructing the subcutaneous lymphatics.
  3. Localized scleroderma of the breast (morphea)—can mimic
    inflammatory carcinoma. More common in younger patients.
9
Q

ARCHITECTURAL DISTORTION ON
MAMMOGRAPHY WITHOUT A
VISIBLE MASS

A
  1. Radial scar/complex sclerosing lesion—see Section 11.7.
  2. Invasive breast cancer—the presence of a correlative abnormality
    on US significantly increases the probability of malignancy.
  3. DCIS—suspicious microcalcification is usually also present.
  4. Sclerosing adenosis—microcalcification may also be present.
  5. Scarring or fat necrosis post biopsy/surgery/infection/trauma—
    clinical history is key. Dystrophic calcification may be present
10
Q

SHRUNKEN BREAST

3

A
  1. Following radiotherapy/trauma/burns—clinical history important. Dystrophic calcification is common. Thoracic radiotherapy in childhood can result in longstanding breast asymmetry due to stunted breast development.
  2. Breast cancer—especially invasive lobular carcinoma, where a discrete mass may not be visible on mammography.
  3. TB*—particularly the sclerosing form
11
Q

MAMMARY DUCT DILATATION
Benign
5

A
  1. Duct ectasia—Dilated subareolar ducts ± debris on US, due to chronic inflammation/fibrosis leading to duct blockage. On a spectrum alongside plasma cell mastitis, periductal mastitis and Zuska’s disease (breast duct fistulas and recurrent abscesses located in and about the nipple).
  2. Physiological changes during lactation.
  3. Blocked ducts—during lactation due to sedimented secretions. Echogenic material in dilated ducts on US.
  4. Papilloma—well-defined intraductal mass with associated duct dilatation. Usually solitary in a central duct, but may be multiple in distal ducts (papillomatosis). Highly vascular ± a vascular stalk on colour Doppler. May contain calcification.
  5. Apocrine metaplasia—associated with fibrocystic disease. Consists of dilated ducts and adjacent septated cysts ± inspissated/calcified secretions. Often seen in patients with extensive cystic disease
12
Q

DUCT DILATATION

Malignant

A
  1. Ductal carcinoma in situ—can present as an intraductal mass with
    duct dilatation (seen on US as a soft-tissue mass filling a duct).
  2. Intraductal papillary carcinoma—indistinguishable from a benign
    papilloma on imaging.
  3. Invasive ductal carcinoma—an irregular mass extending into a
    duct (and therefore widening the duct) is a highly specific sign of
    malignancy, but is not commonly seen in isolation.
13
Q

AXILLARY LYMPHADENOPATHY

A
  1. Nonspecific reactive hyperplasia—enlarged nodes with preserved
    fatty hila and normal node morphology. Idiopathic.
  2. Malignancy—usually from breast cancer. Other common sources
    include lymphoma, leukaemia, melanoma. Involved nodes often
    lose their fatty hilum and elongated shape, becoming more
    rounded. Other features include eccentric cortical thickening and
    capsular irregularity. Involved nodes in lymphoma may be
    markedly hypoechoic, almost cystic in appearance on US. Nodes
    involved by metastatic thyroid or ovarian cancer may contain
    peripheral amorphous calcification. Nodal microcalcification can
    rarely be seen in breast cancer.
  3. Infection—e.g. mastitis, soft-tissue infection in the arm, cat-scratch
    disease, infectious mononucleosis, TB and HIV. Coarse nodal
    calcification suggests TB (or sarcoidosis).
  4. Silicone lymphadenopathy—in patients with silicone breast
    implants that have ruptured/leaked or following silicone injections 344 Aids to Radiological Differential Diagnosis
    into the breast. Silicone deposits in axillary nodes are very dense
    on mammography and cause a ‘snowstorm’ appearance on US.
  5. Connective tissue disease—e.g. rheumatoid arthritis, SLE,
    psoriatic arthritis, dermatomyositis, scleroderma. Patients with a
    history of gold salt therapy for rheumatoid arthritis may have
    punctate high-density gold deposits within axillary nodes (similar
    heavy metal nodal deposits can be seen in patients with large
    tattoos on the arms).
  6. Granulomatous disease—e.g. sarcoidosis, Wegener’s
    granulomatosis
14
Q

MALE BREAST DISEASE

A
  1. Gynaecomastia—most common condition. Proliferation of
    glandular tissue that is typically subareolar, central and
    fan-shaped. Usually bilateral and asymmetrical. On US
    gynaecomastia can have spiculated margins, resembling breast
    carcinoma. In patients on hormonal therapy for gender
    reassignment or prostate cancer, the gynaecomastia is marked
    and may look similar to female breasts.
  2. Pseudogynaecomastia—proliferation of fatty tissue only (no
    glandular proliferation).
  3. Male breast cancer—typically eccentric in location. Invasive
    ductal carcinoma is the most common histological subtype.
    Imaging features are similar to female breast cancer although
    microcalcification is less common. Lesions looking like simple
    cysts should be evaluated carefully as simple cysts do not
    typically occur in men. Complex cysts should be biopsied—a
    solid component within a cyst may represent papillary carcinoma
    (or a benign intraductal papilloma).
  4. Abscess—commonly subareolar in location, with ill-defined
    margins ± surrounding trabecular thickening. Clinical signs of
    infection are typically present.
  5. Haematoma/fat necrosis—e.g. due to trauma.
  6. Metastases—rare. In men, prostate is the most common
    source.
  7. PASH—similar appearance to that seen in women.
  8. Diabetic mastopathy—similar appearance to that seen in
    women.Breast disease and mammography 345
    11
  9. Myofibroblastoma—rare, usually found in older men. Imaging
    features similar to fibroadenoma (but fibroadenoma is
    exceptionally rare in men). See Section 11.4.
  10. Granulomatous mastitis—including TB and sarcoidosis. Very
    rare.
  11. Other soft-tissue masses not specific to the breast—e.g.
    sebaceous cyst, lipoma and others (
15
Q

MRI IN BREAST DISEASE

Indications

A
  1. Evaluate local extent of cancer—when tumour size is uncertain
    on conventional imaging (typically young women with dense
    background breast tissue on mammography). Can also potentially
    assess chest wall invasion.
  2. Lobular carcinoma—may be mammographically occult and can
    be multifocal/bilateral.
  3. Metastatic axillary adenopathy of unknown primary—to identify
    occult breast cancer.
  4. High-risk screening—those with a history of mantle radiotherapy
    or genetic mutation.
  5. Evaluation of implant integrity.
  6. Monitor response to neoadjuvant chemotherapy.
16
Q

MRI IN BREAST DISEASE

Enhancement patterns

A
  1. Mass-like enhancement—see Section 11.1 for characteristics of
    benign and malignant masses. Enhancement curves are important
    for assessing mass lesions: a progressive enhancement pattern is
    usually benign, a plateau pattern is indeterminate and a washout
    pattern is associated with an increased risk of malignancy.
    Fibroadenomas and phyllodes tumours may contain nonenhancing
    septa (a helpful feature).
  2. Non-mass enhancement—ill-defined areas of enhancement that
    do not form a discrete mass. Linear, segmental, clumped and
    clustered ring patterns of enhancement are suspicious for DCIS or
    early invasive carcinoma, but can also be seen in fibrocystic change
    or PASH. Small foci of enhancement <5 mm in size are usually
    benign unless the kinetics are suspicious.
17
Q

Types of breast augmentation

A
  1. Silicone implants.
  2. Saline implants—less dense than silicone implants on
    mammography. These first two implants represent the most
    common types.
  3. Double or triple-lumen implants with silicone and saline
    compartments.
  4. Free silicone/polyacrylamide gel injections (historic practice).
  5. Autologous fat transplantation
18
Q

Complications of breast implants

A
  1. Rupture—saline implants tend to collapse/deflate when rupture
    occurs (the leaked saline is then absorbed by the body), whereas
    silicone implants tend to maintain their shape so rupture may be
    clinically occult. Two types of rupture (see also table below):
    (a) Intracapsular—rupture of the elastomer shell with an intact
    surrounding fibrous capsule. Gel bleed (diffusion of silicone
    through an intact shell) may mimic intracapsular rupture.
    (b) Extracapsular—rupture of both the elastomer shell and
    fibrous capsule, with leakage of silicone into the surrounding
    tissues.
  2. Capsular contracture—contraction of the fibrous capsule
    distorting the shape of the implant, becoming more rounded. The
    capsule may be thickened on US and radial folds may be increased
    in size and number.
  3. Herniation through fibrous capsule—contour bulge on
    mammography.
  4. Haematoma—usually occurs soon after implantation, but chronic
    expanding haematomas have been reported due to intermittent
    bleeding from capsular vessels.
  5. Infection—most common in the early postoperative period. Intact
    implant shell with surrounding fluid which does not contain free
    silicone on silicone-specific MRI sequences.Breast disease and mammography 347
    11
  6. Seroma—periprosthetic fluid collection. May be early or late (>1
    year after implantation).
  7. Breast implant associated anaplastic large cell lymphoma—very
    rare. Can occur many years after implantation. Usually confined
    within the capsule and most commonly presents as an enlarging
    intracapsular effusion around the implant shell, often without a
    discrete mass on imaging. FNA is required to confirm the diagnosis
    and should be performed in any patient with an enlarging
    periimplant effusion occurring >1 year after implantation