Kimberly A Dao MD Anna F Rives MD PhD Liza M Quintana MD Michael A Kritselis DO Michael DC Fishman MD Rutuparna Sarangi MD Priscilla J Slanetz MD MPH From the Departments of Radiology KAD AFR MDCF RS PJS and Pathology MAK Boston University ID: 912260
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Slide1
BI-RADS 5: More than Cancer
Kimberly A. Dao, MD
Anna F. Rives, MD, PhD
Liza M. Quintana, MD
Michael A.
Kritselis
, DO
Michael D.C. Fishman, MD
Rutuparna
Sarangi, MD
Priscilla J.
Slanetz
, MD, MPH
Slide2From the Departments of Radiology (K.A.D., A.F.R., M.D.C.F., R.S., P.J.S.) and Pathology (M.A.K.), Boston University Medical Center, Boston University School of Medicine, 830 Harrison Ave, Moakley Building Suite 1300, Boston, MA 02118; and Department of Pathology, Beth Israel Medical Center, Harvard Medical School, Boston, Mass (L.M.Q.).
Address correspondence to K.A.D. (e-mail: kimberlyanhdao@gmail.com)
Presented as an education exhibit at the 2019 RSNA Annual Meeting and awarded a Certificate of Merit.
Disclosures.—M.D.C.F. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: advisory board member for Hologic; consultant to Zebra Medical Vision; provided expert witness case review for Abramson, Brown and Dugan; institution received a Strategic Alignment Grant from the Association of University Radiologists. Other activities: disclosed no relevant relationships. P.J.S. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: received royalties from UpToDate. Other activities: treasurer and fundraising liaison for the Association of University Radiologists.
Slide3Review classic imaging features of malignancy classified as Breast Imaging Reporting and Data System (
BI-RADS) 5 at mammography, US, and MRI.
Be aware of a variety of benign entities that may manifest with BI-RADS 5 imaging characteristics.
Review radiologic-pathologic correlation for both malignant and benign BI-RADS 5 cases.
Understand the management of BI-RADS 5 entities after a benign biopsy result.
Slide4A BI-RADS 5 assessment is used when the likelihood of malignancy is estimated to be greater than or equal to 95% on the basis of imaging findings. However, not all BI-RADS 5 lesions are malignant.
There are a variety of benign entities that may be categorized as BI-RADS 5, which prompt repeat biopsy or surgical excision when encountered at percutaneous core biopsy.
Radiologists should be aware of these BI-RADS 5 mimickers in order to provide optimal patient care.
Overview
Slide5Imaging Features of Breast CancerClassified as BI-RADS 5
Slide6BI-RADS 5: Mammography
Images in a 36-year-old woman who presented with a palpable lump in the right breast. Mediolateral mammogram
(a)
, mediolateral tomosynthesis image
(b), and magnification craniocaudal mammogram (c) show a large area of architectural distortion (oval) in the upper outer quadrant with associated pleomorphic microcalcifications (blue arrows) and right axillary lymphadenopathy (purple arrow). The results of core biopsy indicated invasive ductal carcinoma.
Typical mammographic features that warrant BI-RADS 5 assessment include irregular mass with
spiculated
margin with or without associated distortion, fine linear branching or pleomorphic calcifications, segmental pleomorphic calcifications, or some combination of these findings.
a.
c.
b.
Slide7BI-RADS 5: Mammography
Images in a 29-year-old woman who presented with a palpable lump in the right breast and axilla. US initially revealed a heterogeneous hypoechoic mass (not shown). Mediolateral oblique
(a)
and craniocaudal
(b) mammograms show segmental fine linear branching calcifications (blue arrows)
and
right axillary lymphadenopathy (purple arrow)
. The results of core biopsy indicated invasive ductal carcinoma with metastatic lymphadenopathy.
Fine linear branching calcifications in a segmental distribution are highly suspicious for malignancy and warrant BI-RADS 5 assessment.
a.
b.
a.
(inset)
Slide8BI-RADS 5: Mammography
Workup of a focal asymmetry seen at screening in a 47-year-old woman. Mediolateral oblique
(a)
and craniocaudal
(b) spot compression mammograms show an irregular high-density mass with spiculated margin (circle). US was performed subsequently (not shown). The results of US-guided biopsy indicated invasive ductal carcinoma.
An irregular high-density mass with
spiculated
margin at mammography is suspicious for malignancy and should be classified as BI-RADS 5.
R
MLO
RCC
a.
b.
Slide9BI-RADS 5: US
Workup of a right breast mass seen at screening mammography in a 53-year-old woman. Radial
(a)
and
antiradial (b) US images show an irregular, hypoechoic mass (oval) at the 3-o’clock position with spiculated and angular margin and an echogenic halo (arrows)
. The results of core biopsy indicated invasive ductal carcinoma.
Typical imaging features of a BI-RADS 5 mass at US include irregular shape, non-parallel orientation, hypoechoic echo pattern,
spiculated
margin, ductal extension, and echogenic halo or posterior shadowing.
a.
b.
Slide10BI-RADS 5: MRI
MR images in a 54-year-old woman who presented with a palpable lump and skin dimpling in the lower inner right breast. Images obtained with mammography and US (not shown) depicted findings classified as BI-RADS 5. Axial
(a)
and sagittal
(b) contrast material–enhanced T1-weighted fat-saturated MR images and axial computer-aided detection (CAD) MR image (c) show an irregular, spiculated mass (arrow) with washout enhancement kinetics (added red closer to washout). The results of core biopsy indicated invasive ductal carcinoma.
Typical MRI features that would warrant BI-RADS 5 assessment include an irregular enhancing mass with
noncircumscribed
margin and type II (plateau) or type III (washout) kinetic curve.
a.
b.
c.
Slide11Axial contrast-enhanced T1-weighted fat-saturated MR image in a 54-year-old woman who presented with a palpable lump and skin dimpling in the lower inner right breast. The results of core biopsy indicated invasive ductal carcinoma.
Invasive ductal carcinoma. Invasive cords and nests of tumor cells infiltrate the breast tissue. Photomicrograph of a biopsy specimen stained with hematoxylin-eosin shows pleomorphic nuclei with prominent nucleoli, some glandular formation, and occasional mitotic figures. (Original magnification, ×200.)
BI-RADS 5: MRI
Slide12BI-RADS 5 Management: Radiologic-Pathologic Correlation
As the likelihood of malignancy for BI-RADS 5 is estimated to be greater than or equal to 95%, all lesions should undergo percutaneous biopsy.
Various outcome analyses have shown that the positive predictive value for a BI-RADS 5 assessment ranges from 78% to 97.5%.
1
A
benign
result at pathologic analysis is considered
discordant
with the imaging findings and warrants repeat biopsy or surgical excision.
Some BI-RADS 5 lesions are ultimately found to be benign.
Slide13Benign Entities Possibly Classified as BI-RADS 5
Slide14Benign Entities Possibly Classified as BI-RADS 5
Atypical infection
Complex sclerosing lesion and radial scar
Fat necrosis
Fibromatosis or desmoid tumor
Granular cell tumor
Granulomatous mastitis
Inflammatory mastitis (autoimmune)
Lymphocytic (diabetic) mastopathy
Mastitis
Myofibroblastoma
Other benign entities (amyloidosis)
Slide15BI-RADS 5 Mimicker: Atypical Infection
Images in a 76-year-old woman who presented with a palpable left axillary lump.
(a, b)
Left mediolateral oblique mammogram
(a) shows a dense irregular mass (pink arrow), which corresponds with US image (b) of the left axilla that shows a complex cystic mass (blue arrow). (c) Axial CAD MR image shows an irregular enhancing mass with washout kinetics (areas in red). The results of core biopsy revealed a Mycobacterium avium intracellulare
infection
.
Active infection can mimic malignancy. Correlation with clinical history and physical examination can aid in diagnosis, although biopsy is often necessary.
a.
b.
c.
Slide16RCC
Atypical Infection: Pathologic Analysis
US image of the left axilla in a 76-year-old woman who presented with a palpable left axillary lump. The results of core biopsy indicated a
Mycobacterium avium
intracellulare infection.
RCC
Atypical infection. Photomicrograph shows non-necrotizing granulomatous inflammation with associated lymphocytes, fat necrosis, and fibrosis.
(Hematoxylin-eosin stain; original magnification, ×200.)
Bacterial culture results from this specimen were positive for
Mycobacterium avium
complex
.
Slide17BI-RADS 5 Mimicker: Atypical Infection
RML
RMCC
LMLO
Clinical Manifestation
Key Imaging Features
Key Histologic Features
Management
Palpable,
often tender mass
Mammography:
Irregular mass or axillary
lymphadenopathy
US:
Irregular mass in breast or axilla, enlarged axillary lymph node with or without necrosis
MRI:
Enhancing mass with or without necrosis
Bacterial cultures grow
Mycobacterium avium
or other atypical organism
Medical management with combination antibiotics to treat infection
Surgical intervention if medical therapy fails
Slide18BI-RADS 5 Mimicker: Complex Sclerosing Lesion
MR images in a 45-year-old woman who presented for baseline high-risk screening. Sagittal
(a)
and axial
(b) contrast-enhanced T1-weighted fat-saturated MR images show an 8-cm irregular enhancing mass with spiculated margin (oval), which was classified as BI-RADS 5. A second-look US examination, subsequent US-guided core biopsy, and surgical excision were performed. US-guided core biopsy and surgical excision revealed a complex sclerosing lesion.
Complex sclerosing lesions and radial scars are common benign entities with suspicious imaging features, necessitating biopsy. The most common manifestation is architectural distortion depicted at screening mammography. The current recommendation is surgical excision in most cases because of the incidence of associated atypia or malignancy.
RMCC
Left
A
xilla US
b.
a.
Slide19Complex Sclerosing Lesion: Pathologic Analysis
Sagittal contrast-enhanced T1-weighted fat-saturated MR image in a 45-year-old woman who presented for a baseline high-risk screening. US-guided core biopsy and subsequent surgical excision helped confirm a
complex sclerosing lesion
.
RML
RMCC
Left
A
xilla US
Complex sclerosing lesion
. Photomicrograph shows epithelial proliferation with usual ductal hyperplasia, glands, cysts, adenosis, and apocrine metaplasia embedded in a
fibroelastotic
stroma. (Hematoxylin-eosin stain; original magnification, ×40.) The disorganized and haphazard architecture of the
complex sclerosing lesion
is evident.
Slide20Clinical Manifestation
Key Imaging Features
Key Histologic Features
Management
Generally asymptomatic
Mammography:
Radial scar <1 cm
Complex sclerosing lesion >1 cm
Architectural distortion with radiating spicules to central
lucency
Occasionally, central
spiculated
mass with or without calcifications
US:
Architectural distortion without central mass
Occasional irregular, iso- or hypoechoic mass with or without posterior shadowing
MRI:
Architectural distortion with or without central
spiculated
mass and enhancement
Benign proliferative lesion with fibroelastic core with radiating entrapped ducts and lobules
Associated with malignancy in 4%–9% of cases (invasive ductal carcinoma or ductal carcinoma in situ)
Surgical excision for most cases (except incidental)
May be safe to follow if imaging findings are concordant, no enhancement at MRI, and the lesion is well-sampled and there is no atypia
BI-RADS 5 Mimicker: Complex Sclerosing Lesion
Slide21BI-RADS 5 Mimicker: Fat Necrosis
Images in an 80-year-old woman who presented for routine screening. Left mediolateral oblique mammogram
(a)
shows an
irregular spiculated mass (circle) with microcalcifications, which corresponds to a left transverse US image (b) that shows an irregular, spiculated hypoechoic mass (arrow) with posterior shadowing at the 5-o’clock position. This mass was classified as BI-RADS 5. Core biopsy of the left breast was initially performed with a spring-loaded device and subsequently with a vacuum-assisted device as the initial biopsy was thought to be discordant. Results of both biopsies indicated fat necrosis.
Fat necrosis is a nonsuppurative inflammatory process that may be incidental at imaging. Clinical history of surgical or accidental trauma would aid in diagnosis.
RCC
RCC
a.
b.
Slide22RCC
Fat Necrosis: Pathologic Analysis
Mammogram in an 80-year-old woman who presented for a routine screening.
Core biopsy of the left breast was initially performed with a spring-loaded device and subsequently with a vacuum-assisted device as the initial biopsy was thought to be discordant. Results of both biopsies indicated fat necrosis.
RCC
Right Breast US 10:00 Sagittal
Right Breast US 10:00 Transverse
Left Breast US 5:00 Transverse
Fat necrosis. Photomicrograph shows a dense infiltrate of macrophages, foamy histiocytes, and lymphocytes with associated cystic spaces. Dense collagenous breast tissue is present in the background.
(Hematoxylin-eosin stain; original magnification, ×100.)
Slide23BI-RADS 5 Mimicker: Fat Necrosis
RML
RMCC
LMLO
Clinical Manifestation
Key Imaging Features
Key Histologic Features
Management
Palpable ill-defined breast mass
Sometimes bruising, skin tethering, or dimpling
Either painless or tender
May have history of trauma, surgery, or radiation
Mammography:
Asymmetry or radiolucent mass with or without coarse calcifications
US:
Variable:
Hypoechoic mass with posterior acoustic shadowing, complex mass, or hyperechoic mass
MRI:
Central fat signal intensity at T1- and T2-weighted imaging
Hemosiderin hypointense rim
Variable enhancement with peripheral thin enhancement or no enhancement
Early:
Cystic
spaces surrounded by lipid-laden histiocytes, foreign body-type giant cells, with or without acute inflammatory infiltrate
Chronic:
Fibroblastic proliferation, collagen deposition, foamy histiocytes, foreign body–type giant cells
Conservative
Slide24RCC
BI-RADS 5 Mimicker: Fibromatosis or Desmoid Tumor
Images in a 47-year-old woman who presented with focal left breast pain. Mammography was unrevealing (not shown).
(a)
US image shows an irregular hypoechoic mass (arrow) involving the breast and pectoralis muscle with a large
feeding vessel (red area in
a
)
.
(b, c) Axial contrast-enhanced T1-weighted fat-saturated (b) and axial CAD (c) MR images show a suspicious irregular enhancing mass (circle) with mixed kinetics. The results of a core biopsy indicated fibromatosis.
Fibromatosis or desmoid tumor is a benign locally aggressive spindle cell tumor arising from the aponeurosis overlying the pectoralis muscle or occurs secondary to prior trauma or surgery. Management is wide surgical excision, given the high risk of local recurrence.
RCC
a.
b.
c.
Slide25RCC
Fibromatosis or Desmoid Tumor: Pathologic Analysis
Axial contrast-enhanced T1-weighted fat-saturated MR image in a 47-year-old woman who presented with focal left breast pain. The results of a core biopsy indicated fibromatosis, and the patient subsequently underwent surgical excision.
RCC
Fibromatosis or desmoid tumor. Photomicrograph shows uniform bland spindle cells in long sweeping fascicles in a collagenous background.
(Hematoxylin-eosin stain; original magnification,
×100.)
The morphology and nuclear labeling with
β
-catenin (not pictured) support the diagnosis of desmoid fibromatosis.
Slide26BI-RADS 5 Mimicker: Fibromatosis or Desmoid Tumor
RML
RMCC
LMLO
Clinical Manifestation
Key Imaging Features
Key Histologic Features
Management
Premenopausal women with painless, palpable, firm mass, near or fixed to pectoralis muscle with or without nipple or skin retraction
History of trauma, surgery, or exogenous hormone therapy
Genetic mutations:
a
denomatous polyposis coli or
β
-catenin
Mammography:
Irregular,
spiculated
mass arising from aponeurosis overlying pectoralis muscle
With or without skin or nipple retraction
No lymphadenopathy
US:
Irregular hypoechoic mass with angular or indistinct margin
No posterior features
Variable internal vascularity
MRI:
Irregular,
spiculated
mass T1-isointense to hypointense and T2-hyperintense with variable enhancement characteristics
Benign locally aggressive spindle cell tumor
Spindle cells composed of fibroblasts or myofibroblasts, with little to no nuclear pleomorphism and variable amounts of collagen
Infiltrate ducts, lobules, and muscle
Lymphoid aggregates may be seen at the periphery
Wide surgical excision, given high risk of local recurrence
(20%–30%)
Slide27RCC
BI-RADS 5 Mimicker: Granular Cell Tumor
US images in a 76-year-old woman who presented with an enlarging mass in the upper inner left breast that was shown at mammography (not shown). Left radial
(a)
and antiradial (b) US images show an
irregular, heterogeneously hypoechoic mass with an indistinct margin (arrow)
at the 11-o’clock position that was classified as BI-RADS 5. The results of a core biopsy indicated a granular cell tumor.
RCC
Granular cell tumor is a rare soft-tissue tumor originating from Schwann cells that may affect the breast. Imaging features mimic primary breast cancer, prompting biopsy. Management is wide local excision, as it is locally aggressive and 1% of cases are malignant.
a.
b.
Slide28RCC
Granular Cell Tumor: Pathologic Analysis
Left
antiradial
US image in a 76-year-old woman who presented with an enlarging mass at the 11-o’clock position in the upper inner left breast. The results of a core biopsy indicated a granular cell tumor.
RCC
Granular cell tumor. Photomicrograph shows a granular cell tumor composed of infiltrating sheets and clusters of large round to polygonal cells with bland centrally located nuclei.
(Hematoxylin-eosin stain; original magnification, ×100.)
The cells have abundant eosinophilic cytoplasm with prominent granules (inset, original magnification
×600
). The tumor cells are positive for S100 and negative for
cytokeratins
(not pictured).
Slide29BI-RADS 5 Mimicker: Granular Cell Tumor
RML
RMCC
LMLO
Clinical Manifestation
Key Imaging Features
Key Histologic Features
Management
Premenopausal middle-aged women (more common in African Americans) with painless, palpable, firm mass, near chest wall, or asymptomatic
With or without skin retraction, nipple inversion
Associated with neurofibromatosis type 1 and
Bannayan
-
Ruvalcaba
-Riley syndrome, LEOPARD syndromes
Mammography:
Most common in upper, inner breast posteriorly
Irregular,
spiculated
mass without calcifications
US:
Irregular, hypoechoic mass with angular or indistinct margin
With or without posterior shadowing
MRI:
T1-hypointense mass with heterogeneous enhancement
Infiltrating sheets or cords of polygonal bland cells, abundant eosinophilic granular cytoplasm and round or oval nuclei with prominent nucleoli
May be near small nerve bundles and with infiltrative margins
Benign in 99% of cases
Malignant: spindling, nuclear pleomorphism, increased mitotic activity and necrosis, usually > 5 cm in size
Wide surgical excision
Slide30RCC
BI-RADS 5 Mimicker: Granulomatous Mastitis
Images in a 37-year-old woman who presented with a palpable right breast lump. Initial mammography and US were negative (not shown). Axial
(a)
and sagittal (b) contrast-enhanced T1-weighted fat-saturated MR images obtained several weeks later show an irregular mass with rim enhancement and surrounding regional
nonmass
enhancement (blue arrows)
in the right upper outer breast, classified as BI-RADS 5. Second-look US image
(c)
shows irregular, heterogeneously hypoechoic masses (pink arrow) in the upper outer quadrant. Results of a core biopsy indicated granulomatous mastitis.
RCC
Granulomatous mastitis is a benign rare process affecting young women, mimicking inflammatory breast cancer. It is often associated with pregnancy and breast feeding. Management is corticosteroid therapy.
a.
b.
c.
Slide31Granulomatous Mastitis: Pathologic Analysis
Axial contrast-enhanced T1-weighted fat-saturated MR image in a 37-year-old woman who presented with a palpable right breast lump. Results of a core biopsy indicated granulomatous mastitis.
Granulomatous mastitis. Photomicrograph shows
lobulocentric
granulomatous and chronic inflammation with numerous granuloma rings with central neutrophilic clusters. (Hematoxylin-eosin stain; original magnification, ×40.)
Slide32BI-RADS 5 Mimicker: Granulomatous Mastitis
RML
RMCC
LMLO
Clinical Manifestation
Key Imaging Features
Key Histologic Features
Management
Reproductive-aged, parous woman, typically within 6 years of childbearing
Palpable lump, with or without pain
Mammography:
Negative, or asymmetry, irregular, indistinct mass(es), possible architectural distortion
With or without trabecular and skin thickening, lymphadenopathy
US:
Irregular, indistinct hypoechoic mass or masses
With or without edema, complex fluid collections, ductal dilatation, hypervascularity
MRI:
Irregular mass or masses with internal rim or heterogeneous enhancement
Regional, segmental
nonmass
enhancement
Primarily lobulocentric
noncaseating granulomas, neutrophils and lymphocytesNo organisms seen on special stains and cultures
CorticosteroidsSometimes surgery
Slide33RCC
BI-RADS 5 Mimicker: Inflammatory Mastitis
Images in a 69-year-old woman with a history of left breast cancer who presented with erythema, induration, and
peau
d’orange in the lower inner left breast. Left mediolateral oblique (a)
and left craniocaudal
(b)
mammograms and US image obtained at the 11-o’clock to 12-o’clock position
(c)
show a stable irregular mass (oval and arrow) in the lower inner breast but new skin thickening (curved line), which is suspicious for inflammatory breast cancer. Results of a core biopsy indicated lymphoplasmacytic granulomatous infiltrate consistent with lupus mastitis. The patient had a clinical history of systemic lupus erythematosus.
a.
b.
c.
Slide34RCC
Inflammatory Mastitis from Lupus: Pathologic Analysis
US image at the 11-o’clock to 12-o’clock position in a 69-year-old woman with a history of left breast cancer who presented with erythema, induration, and
peau
d’orange. Results of a core biopsy indicated lymphoplasmocytic
granulomatous infiltrate consistent with lupus mastitis.
Inflammatory mastitis from lupus. Photomicrograph shows dense stromal fibrosis with perivascular and focal
perilobular
lymphoplasmacytic infiltrates.
(Hematoxylin-eosin stain; original magnification, ×200.)
Some secondary follicles with reactive germinal centers (lymphoid aggregate at right) are present.
Slide35BI-RADS 5 Mimicker: Inflammatory Mastitis
RML
RMCC
LMLO
Clinical Manifestation
Key Imaging Features
Key Histologic Features
Management
Breast pain, swelling
With or without skin thickening, erythema, induration,
peau
d’orange
appearance
Sometimes fever
With or without clinical history of systemic lupus erythematosus
Mammography:
Irregular, indistinct mass or asymmetry with or without calcifications
With or without skin thickening
US:
Irregular, indistinct hypoechoic mass or heterogeneous area
With or without calcifications
With or without skin thickening
MRI: Ill-defined, heterogeneous rim- enhancing mass involving the subcutaneous fat
Hyaline fat necrosis, sclerosis, calcifications, lymphoplasmacytic granulomatous infiltration, and lymphocytic vasculitis
Medical combination therapy including antimalarial agents and corticosteroids
Surgery may trigger an additional flare
Slide36BI-RADS 5 Mimicker: Lymphocytic Mastopathy
Left Breast
US
10:00
Images in a 63-year-old woman who presented with a palpable right breast lump. Right craniocaudal mammogram (a) shows an irregular mass with associated architectural distortion (circle)
. US image
(b)
obtained in the location of the palpable lump shows an
irregular hypoechoic mass (arrows)
at the 12-o’clock position with posterior shadowing. Review of the patient’s clinical history revealed long-standing diabetes. The results of a core biopsy indicated diabetic mastopathy.
Right Breast US 7:00 Sagittal
a.
A history of long-standing insulin-dependent diabetes may allow a BI-RADS 4 rather than 5 assessment and help avoid discordant biopsy.
2
b.
Slide37Right Breast US 7:00 Transverse
Right Breast US 7:00 Sagittal
RCC
Lymphocytic Mastopathy: Pathologic Analysis
Right Breast
US
12:00 palp
US image in a 63-year-old woman who presented with a palpable right breast lump. Results of a core biopsy indicated lymphocytic mastopathy.
Lymphocytic mastopathy. Photomicrograph shows benign breast tissue with dense collagenized stroma and mild
perilobular
lymphocytic infiltration consistent with lymphocytic (diabetic) mastopathy. (Hematoxylin-eosin stain; original magnification, ×100.)
Slide38RML
RMCC
LMLO
Clinical Manifestation
Key Imaging Features
Key Histologic Features
Management
Clinical history of insulin- dependent diabetes (type 1> type 2) in 30- to 60-year-old women
Mobile, firm nontender mass or masses
With or without skin thickening, or asymptomatic
Clinical findings are often bilateral
Mammography:
Noncalcified dense asymmetry, or indistinct or
spiculated
mass
May be occult in dense breasts
US:
Hypoechoic mass or area with indistinct or
spiculated
margin and posterior shadowing
No internal vascularity
MRI:
Irregular T2-hypointense mass
With or without focal slow persistent enhancement
Keloidal fibrosis, epithelioid fibroblasts, and dense perivascular lymphocytic infiltrates surround lobules, ducts, and blood vessels. Lymphocytes are predominantly B cells
Core biopsy recommended to establish histologic diagnosis
Conservative:
Self-limited natural course with no risk of malignancy
BI-RADS 5 Mimicker: Lymphocytic Mastopathy
Slide39BI-RADS 5 Mimicker: Mastitis
Images in a 38-year-old woman who presented with a palpable left breast lump and nipple pain. Right
(a)
and left
(b) mediolateral oblique mammograms show a global asymmetry (oval) involving the upper left breast with associated nipple retraction (blue arrow) and axillary adenopathy (purple arrow in b)
.
(c–e)
US images in the left breast at the 1-o’clock position
(c)
and 2-o’clock position (d) and in the left axilla (e) show ill-defined
hypoechoic nonmass findings with posterior shadowing (pink arrows) and
axillary lymph nodes with thickened cortices (purple arrows). These imaging findings were classified as BI-RADS 5. Results of a core biopsy indicated acute and chronic inflammation. Symptoms resolved after antibiotic therapy.
Mastitis can sometimes manifest with suspicious imaging features and necessitate biopsy.
RML
RMCC
b.
a.
c.
d.
e.
Slide40Mastitis: Pathologic Analysis
Left mediolateral oblique mammogram in a 38-year-old woman who presented with a palpable left breast lump and nipple pain. Results of a core biopsy indicated acute and chronic inflammation.
RML
RMCC
LMLO
R
MLO
Left
Breast
US
1:00 palp
Left
Breast
US
2:00 palp
Left
Axilla US
Mastitis. Photomicrographs show acute and chronic inflammation, abscess, and
nonnecrotizing granulomatous inflammation. (Hematoxylin-eosin stain; original magnification, left: ×40, right: ×100.)
Slide41BI-RADS 5 Mimicker: Mastitis
RML
RMCC
LMLO
Clinical Manifestation
Key Imaging Features
Key Histologic Features
Management
Unilateral breast localized pain, erythema, and warmth.
Nonspecific
symptoms
like
fever, malaise, fatigue,
and generalized body aches
Mammography:
Increased breast density, trabecular and skin thickening with or without subareolar ductal dilatation, axillary adenopathy
US:
Soft-tissue edema and skin thickening with hyperemia and increased echogenicity with or without ductal debris with ductal wall thickening
MRI:
Increased T2 signal intensity corresponding to edema,
nonmass
enhancement focally
Complication: Abscess, sinus tract, or fistula formation
Pathologic analysis:
Mixed acute and chronic inflammatory cells,
with or without plasma cells, fat necrosis, abscess
Etiology:
Staphylococcus aureus
and
Streptococcus
most common
Smokers: Squamous metaplasia of lactiferous ducts (SMOLD) leads to keratin plugs, duct obstruction, and infection
Antibiotics, warm compresses, analgesics
Puerperal:
Continue regular breast feeding and maximize emptying of the breast
Smokers:
Encourage smoking cessation
Abscess:
US-guided aspiration for drainage, obtaining culture and sensitivity
Slide42BI-RADS 5 Mimicker: Myofibroblastoma
Images in a 61-year-old woman who presented for routine screening. Right craniocaudal mammogram
(a)
shows an irregular dense mass with indistinct margin (oval) corresponding to a transverse US image (b) of an irregular, hypoechoic mass with indistinct margin (arrow) at the 7-o’clock position and posterior shadowing. These imaging findings were classified as BI-RADS 5. Core biopsy results indicated myofibroblastoma
.
a.
b.
Slide43Right Breast US 7:00 Transverse
Right Breast US 7:00 Sagittal
RCC
Myofibroblastoma
: Pathologic Analysis
Right craniocaudal mammogram in a 61-year-old woman who presented for routine screening. Results of core biopsy indicated
myofibroblastoma
.
Myofibroblastoma
. Photomicrograph shows short fascicles of bland spindle cells, bands of dense collagen, and admixed adipose tissues.
(Hematoxylin-eosin stain; original magnification, ×100.)
Immunohistochemical stains (not shown) showed the lesion to be positive for BCL-2, CD34, estrogen receptors, and progesterone receptors, which are consistent with
myofibroblastoma
.
Slide44BI-RADS 5 Mimicker: Myofibroblastoma
RML
RMCC
LMLO
Clinical Manifestation
Key Imaging Features
Key Histologic Features
Management
Palpable, painless mobile mass
Slightly more common in men than women
Mammography:
Solitary round or oval
isodense
to dense mass, 1 cm to 4 cm in size, usually no calcifications
US:
Circumscribed, solid, homogeneous hypoechoic oval or round mass, sometimes ill-defined with posterior shadowing
MRI:
Round or oval mass with variable T2 signal hyperintensity and internal enhancement
Benign tumor composed of packs of spindle cells, interposed thick bands of eosinophilic collagen
Complete surgical excision is recommended, as
myofibroblastoma
may recur if not entirely excised
3
Slide45Benign breast lesions may manifest with imaging features that are worrisome for malignancy, leading to a BI-RADS 5 assessment.
A benign percutaneous biopsy result for a BI-RADS 5 assessment warrants either repeat percutaneous biopsy or excision.
The most common BI-RADS 5 mimickers are chronic and inflammatory mastitis, granulomatous mastitis, fat necrosis, complex sclerosing lesions, granular cell tumors, and infection.
Radiologists should be aware of benign BI-RADS 5 mimickers to provide optimal patient care.
Summary
Slide46Cho SH, Park SH. Mimickers of breast malignancy on breast sonography. J Ultrasound Med 2013;32(11):2029–2036.
Heller SL, Moy L. Imaging features and management of high-risk lesions on contrast-enhanced dynamic breast MRI. AJR Am J
Roentgenol
2012;198(2):249–255.
Kim YR, Kim HS, Kim H-W. Are Irregular Hypoechoic Breast Masses on Ultrasound Always Malignancies?: a Pictorial Essay. Korean J Radiol 2015;16(6):1266–1275.
Mario J, Venkataraman S,
Dialani
V,
Slanetz
PJ. Benign breast lesions that mimic cancer: determining radiologic-pathologic concordance. Appl
Radiol
2015;44(9):28–32.
Spruill L. Benign mimickers of malignant breast lesions. Semin Diagn Pathol
2016;33(1):2–12.
Yao MM-S, Joe BN, Sickles EA, Lee CS. BI-RADS Category 5 Assessments at Diagnostic Breast Imaging: outcomes Analysis Based on Lesion Descriptors. Acad
Radiol 2019;26(8):1048–1052.
Suggested Readings
Slide47References
Yao MM-S, Joe BN, Sickles EA, Lee CS. BI-RADS Category 5 Assessments at Diagnostic Breast Imaging: outcomes Analysis Based on Lesion Descriptors.
Acad
Radiol 2019;26(8):1048–1052.Kim YR, Kim HS, Kim H-W. Are Irregular Hypoechoic Breast Masses on Ultrasound Always Malignancies?: a Pictorial Essay. Korean J Radiol
2015;16(6):1266–1275.
Raut P,
Lillemoe
TJ, Carlson A.
Myofibroblastoma of the breast. Appl Radiol 2017;46:42–44
.