Download Cystic Lesions of the Breast: Sonographic-Pathologic

Radiology
Breast Imaging
Wendie A. Berg, MD, PhD
Cristina I. Campassi, MD2
Olga B. Ioffe, MD
Index terms:
Breast, biopsy, 00.1261, 00.1262
Breast, cysts, 00.721, 00.722, 00.723
Breast neoplasms, diagnosis, 00.311,
00.3115, 00.312, 00.319, 00.324,
00.327, 00.719
Breast neoplasms, US, 00.12982,
00.12985, 00.12989
Published online
10.1148/radiol.2272020660
Radiology 2003; 227:183–191
Abbreviations:
CNB ⫽ core-needle biopsy
DCIS ⫽ ductal carcinoma in situ
IDC ⫽ invasive ductal carcinoma
1
From the Department of Radiology
(W.A.B., C.I.C.), Greenebaum Cancer
Center (W.A.B.), and Department of Pathology (O.B.I.), University of Maryland
Medical Center, 419 W Redwood St,
Suite 110, Baltimore, MD 21201. From
the 2001 RSNA scientific assembly. Received May 31, 2002; revision requested June 27; final revision received
September 23; accepted September 30.
Address correspondence to W.A.B.
(e-mail: [email protected]).
Current address:
Cystic Lesions of the Breast:
Sonographic-Pathologic
Correlation1
PURPOSE: To understand the pathologic basis for sonographic features of cystic
lesions of the breast and determine appropriate assessment and management
recommendations for these lesions based on sonographic appearance.
MATERIALS AND METHODS: From a database of 2,072 image-guided procedures
performed from July 1995 through September 2001, 150 cystic lesions were identified. Diagnosis was established with fine-needle aspiration (n ⫽ 55), 14-gauge
core-needle biopsy (n ⫽ 81), or both (n ⫽ 14). Excision was performed for all
malignant (n ⫽ 18) and atypical (n ⫽ 2) lesions and for 11 benign lesions, which
recurred or enlarged at follow-up. Imaging follow-up was available for 92 of 119
benign lesions. Targeted sonography was performed with high-frequency (10-MHz
center frequency) transducers. Imaging and histopathologic, cytologic, and/or microbiologic findings were reviewed. Lesions were categorized as simple cysts, complicated cysts (imperceptible wall, acoustic enhancement, low-level echoes), clustered microcysts, cystic masses with a thick (perceptible) wall and/or thick (ⱖ0.5
mm) septations, intracystic or mixed cystic and solid masses (at least 50% cystic), or
predominantly solid masses with eccentric cystic foci.
RESULTS: Of 150 lesions, 16 were simple cysts aspirated for symptomatic relief. Of
38 lesions characterized as complicated cysts and one cyst with thin septations,
none proved malignant, nor did any of 16 lesions characterized as clustered microcysts. Of 23 masses with thick indistinct walls or thick septations, seven proved
malignant. Of 18 intracystic or mixed cystic and solid masses, four proved malignant. Of 38 predominantly solid masses with eccentric cystic foci, seven proved
malignant.
2
Department of Radiology, Johns
Hopkins University School of Medicine, Baltimore, Md.
CONCLUSION: Symptomatic complicated cysts generally warrant aspiration. All
clustered microcysts were benign, but further study is required. Cystic lesions with
thick indistinct walls and/or thick septations (ⱖ0.5 mm), intracystic masses, and
predominantly solid masses with eccentric cystic foci should be examined at biopsy;
18 of 79 of such complex cystic lesions proved malignant in this series.
©
Author contributions:
Guarantor of integrity of entire study,
W.A.B.; study concepts and design,
W.A.B.; literature research, W.A.B.,
C.I.C.; clinical studies, W.A.B., C.I.C.,
O.B.I.; data acquisition and analysis/
interpretation, W.A.B., C.I.C., O.B.I.;
manuscript preparation and definition
of intellectual content, W.A.B.; manuscript editing, revision/review, and final version approval, W.A.B., C.I.C.,
O.B.I.
©
RSNA, 2003
RSNA, 2003
Breast sonography is appropriate in the initial evaluation of a woman younger than 30
years with a palpable lump and in the adjunctive evaluation of mammographic masses,
persistent focal asymmetric densities, and palpable abnormalities not seen mammographically (1). Sonographically guided core-needle biopsy (CNB) is a readily performed, diagnostically accurate alternative to stereotactic or excisional biopsy (2,3). Sonographically
guided aspiration of symptomatic cysts, complicated cysts, and possible abscesses is also
readily performed. Sonographically guided fine-needle aspiration with multiple passes
with a 20 –25-gauge needle is not favored for solid nonpalpable masses because of the
substantial insufficient sample rate, averaging 10% in a multicenter trial (4).
Sonographic feature analysis of solid masses continues to improve (5), though observer
variability continues to be problematic in avoiding biopsy (6,7). An illustrated Breast
Imaging Reporting and Data System (BI-RADS) ultrasonographic lexicon (8) may be helpful in improving observer performance.
Confusion remains in the description and management of complicated cysts and com183
Radiology
plex cystic lesions of the breast (8 –10).
We sought to understand the pathologic
basis of the sonographic features of cystic
lesions of the breast and to determine
appropriate assessment and management
recommendations for these lesions based
on sonographic appearance.
MATERIALS AND METHODS
Patients and Lesions
From a database of 2,072 image-guided
breast procedures performed from July
1995 through September 2001 at our institution, we sought to identify lesions
with a prospectively recorded cystic component at sonography. In 133 patients,
150 pathologically proven cystic lesions
were identified, representing 7.2% of all
lesions. Of the 150 lesions, 92 (61%) were
palpable. The mean age of patients was
48.4 years (age range, 14 –96 years). The
mean lesion diameter was 22 mm (range,
4 –150 mm). Diagnosis was established
with sonographically guided aspiration
alone in 55 lesions from which fluid was
withdrawn by using an 18- or 20-gauge
needle and sent for cytologic examination and/or culture. For 81 lesions, sonographically guided CNB was performed
by using a 14-gauge automated biopsy
gun (Monopty; Bard, Covington, Ga).
Initial aspiration was performed in 14 lesions, followed by CNB owing to persistence of a thick wall or a solid component. A mean of 4.1 (range, 1.0 – 8.0)
passes were made per CNB.
Our database is password protected,
and our institutional review board did
not require its approval or individual patient consent for review. Our database
includes details of CNB and directional
vacuum-assisted biopsies, aspirates when
cytologic studies and/or cultures were
performed, needle localizations, and ductograms. The database includes the mammographic and sonographic appearance
of lesions as prospectively recorded. Of
the 2,072 total procedures, 500 (24.1%)
demonstrated a malignancy.
Follow-up after Fine-Needle
Aspiration or CNB
Surgical excision was performed after
any atypical (n ⫽ 2) or malignant (n ⫽
18) result and was recommended for lesions with initial benign results, which
recurred (n ⫽ 4) or increased (n ⫽ 7) at
follow-up. The excised benign lesions
were as follows: two recurrent cysts, two
recurrent collections (one fat necrosis
and/or seroma and one abscess), two papillomas that enlarged at follow-up, a
184
䡠
Radiology
䡠
April 2003
third benign papilloma in a patient with
persistent nipple discharge, one infarcted
fibroadenoma 13 cm in diameter and another palpable fibroadenoma, one scar
tissue developing at an abscess site, and
one enlarging lactating adenoma.
If the lesion resolved after aspiration,
and the cytologic specimen was benign,
no further follow-up was recommended.
Lesions proving to be benign cysts at
CNB were not specifically followed up. If
a proven abscess resolved clinically with
antibiotics, no further follow-up was recommended. With a specific benign concordant result at CNB, such as fibroadenoma, lesions were followed up annually. For all other benign results, 6-,
12-, and 24-month follow-up was recommended. After a concordant benign result (other than cyst or abscess) at CNB or
fine-needle aspiration, with no atypia, we
accepted as a defined standard those lesions that were excised, subjected to another biopsy or reaspirated with the same
benign result, gone or decreasing in size
at any follow-up, or stable at 23 full
months of follow-up. Of the 95 lesions
subjected to CNB, 73 (77%) had an acceptable standard. Of the 55 lesions subjected to only aspiration, 53 (96%) had
an acceptable standard.
Ninety-two proven benign lesions had
at least one follow-up (range, 2– 60
months; mean, 24 months; median, 23
months). Forty-nine lesions had at least
24 months of follow-up after initial diagnostic aspiration or CNB. Twenty-seven
lesions proven benign at CNB (n ⫽ 16),
aspiration (n ⫽ 8), or both (n ⫽ 3) have
not had documented follow-up. The status of the 19 lesions after CNB without
further follow-up include six fibrocystic
changes; three fibroadenomas; two focal
fibrosis; two abscesses; two papillomas;
and one each sclerosing adenosis, apocrine metaplasia, cyst, and fat necrosis.
The eight lesions with initial diagnosis at
aspiration and no further follow-up include five simple cysts, one abscess, and
two apocrine metaplasia (one sonographically simple cyst and one clustered
microcysts, both in the same patient).
Imaging and Interpretation
Sonography was performed in all 150
lesions by using a broad-bandwidth linear-array transducer with a center frequency of 10 MHz supplemented by a
transducer with a center frequency of 7.5
MHz, as needed, to penetrate larger breasts
(Performa, Acoustic Imaging, Tempe, Ariz;
or Elegra, Siemens Medical Systems, Issaquah, Wash). Craniocaudal and medio-
lateral oblique mammograms were obtained in 127 lesions by using a LoRad
MIV unit (Hologic, Bedford, Mass) or
DMR Plus unit (GE Medical Systems, Milwaukee, Wis). Spot compression views
were obtained of all lesions manifested as
asymmetric densities and of all palpable
masses. Spot magnification views were
obtained of all masses not clearly circumscribed on the original or spot compression views. Two radiologists (W.A.B. and
C.I.C.) specializing in breast imaging reviewed the mammographic (n ⫽ 127)
and sonographic (n ⫽ 150) images again
and recorded features in consensus. All
authors compared the imaging features
with histopathologic and cytologic findings and/or culture diagnoses.
Anechoic masses with an imperceptible circumscribed border and acoustic enhancement were classified as simple
cysts. Complicated cysts were defined by
Mendelson et al (8) as lesions with homogeneous low-level echoes that otherwise
meet the criteria of a simple cyst. Circumscribed cystic lesions with imperceptible
wall and fluid-debris level were included
as complicated cystic lesions. Lesions
composed entirely of clusters of tiny (2–5
mm) anechoic foci with no discrete solid
component were termed clustered microcysts. Septations within a cyst were defined as thin (⬍0.5 mm, representing the
combined thickness of two myoepithelial
and epithelial cell layers) or thick (ⱖ0.5
mm). A thick wall was any perceptible
wall.
Intracystic masses had a discrete solid
mural mass within a cyst. Grouped with
these were mixed cystic and solid masses
with at least 50% cystic component.
Masses that were at least 50% solid with
eccentric cystic foci were considered the
final category.
Sonographic and mammographic margins of the masses were recorded. For circumscribed lesions, the shape (round,
oval, lobular, or tubular) was recorded.
Lesions of mammographically focal increased density without convex borders
were classified as focal asymmetries.
RESULTS
Of 150 cystic lesions, 16 were classified as
simple cysts, 38 as complicated cysts, one
as a cyst with thin septations, 16 as clustered microcysts, 23 as masses with thick
wall and/or thick septations, 18 as intracystic or mixed cystic and solid masses,
and 38 as mainly solid masses with eccentric cystic foci (Table 1). Of the 150
lesions, 18 (12%) proved to be maligBerg et al
Radiology
TABLE 1
Subclassification, Method of Sampling, and Rates of Malignancy
of 150 Cystic Lesions
Sonographic Feature
Aspiration*
CNB†
Aspiration
and CNB
Malignancy
Simple cyst (n ⫽ 16)
Complicated cyst (n ⫽ 38)
Cyst with thin septations (n ⫽ 1) ‡
Clustered microcysts (n ⫽ 16)
Mass with thick wall and/or thick septations
(n ⫽ 23) ‡
Intracystic mass, mixed cystic and solid
(n ⫽ 18) §
Solid mass with eccentric cystic foci (n ⫽ 38)
15
22
1
5
NA
13
NA
11
1
3
NA
NA
0 (0)
0 (0)
0 (0)
0 (0)
9
10
4
7 (30)
2
1
13
34
3
3
4 (22)
7 (18)
55
81
14
18 (12)
Total
Note.—Data are the number of lesions. Data in parentheses are percentages. NA ⫽ not applicable.
* Aspirations were performed with sonographic guidance by using an 18 –20-gauge needle and
single pass.
† Performed with 14-gauge automated biopsy gun with sonographic guidance.
‡ Thin septations are defined as ⬍0.5 mm, thick septations are defined as ⱖ0.5 mm.
§ Fourteen intracystic masses and four masses that were mixed cystic and solid and at least 50%
cystic.
nant, and 15 (83%) of 18 malignant lesions were palpable.
Simple Cysts
Sixteen sonographically simple cysts
were aspirated because they were tender
and palpable. One lesion required CNB
owing to questionable persistence of the
wall after aspiration (Table 1) and proved
to be due to apocrine metaplasia. One
abscess had the appearance of a simple
cyst (Table 2). Follow-up was available for
all but three simple cysts. Of 13 cysts
with follow-up, five (39%) recurred and
one of those was excised owing to a thick
wall at recurrence (yielding a benign cyst)
(Table 3).
Complicated Cysts
Of the 38 sonographically complicated
cysts, 19 yielded benign cyst fluid (Fig 1);
six, abscesses; five, fibrocystic changes;
four, apocrine metaplasia; two, fat necrosis; and one each, papilloma and galactocele (Table 2). At times, echogenic foci
could be seen to be moving within the
cyst fluid (Fig 2). Seventeen cysts were
palpable and none proved to be malignant. Of 34 complicated cysts with an
acceptable standard, one galactocele recurred and was reaspirated (Table 3).
Three apparent complicated cysts were
excised: one recurrent cyst, one papilloma that enlarged due to infarction, and
one fat necrosis and/or seroma at a site of
prior benign surgical biopsy that was subjected to three aspirations with recurrence.
Volume 227
䡠
Number 1
Cyst with Thin Septations
One palpable 4-cm cyst containing
thin (⬍0.5 mm) septations (Fig 3) was
aspirated to resolution with benign cytologic results and has recurred at 12
months.
Clustered Microcysts
Of 16 masses characterized as clusters
of microcysts (Fig 4), seven (44%) were
due to apocrine metaplasia; six (38%),
fibrocystic changes; two (13%), cysts; and
one (6%), fibroadenoma, with no malignancies (Table 2). Twelve (75%) of 16
masses had an acceptable standard. One
cluster of microcysts had slightly enlarged at initial 6-month follow-up and
was subjected to another CNB with the
same result of fibrosis with cysts; this
mass has been stable at 53-month followup.
Masses with Thick Wall and/or
Thick Septations
Another 23 cystic lesions had thick
(ⱖ0.5 mm) walls and/or thick (ⱖ0.5 mm)
septations, of which seven (30%) were
malignant (Figs 5–7). Of the seven malignancies, six (86%) were invasive ductal
carcinomas (IDCs) grade 3, one of which
had an associated intraductal component, and one was IDC grade 2 (Table 2).
Of 18 abscesses, eight (44%) manifested
as thick-walled cystic masses (Fig 8). Two
abscesses with this appearance recurred:
one was reaspirated and one was surgically incised and drained (Table 3). An-
other patient developed an irregular mass
at the site of the initial abscess drainage;
the mass was excised, showing scar tissue. Other benign causes of thick-walled
cysts included simple cysts (including
one with rupture and chronic inflammation), fibrocystic changes, and fat necrosis (Table 2). One fibrocystic change with
atypia at cytologic examination recurred
and was excised with benign results.
Intracystic or Mixed Cystic and
Solid Masses
Of 18 total intracystic (n ⫽ 14) or
mixed cystic and solid (n ⫽ 4, at least
50% cystic) masses, four (22%) proved to
be malignant, including two intracystic
papillary carcinomas (ductal carcinoma
in situ [DCIS]) (Fig 9), one infiltrating
and intraductal carcinoma (Fig 10), and
one IDC grade 3. Five (28%) were due to
benign papillomas (Table 2). One large
galactocele appeared to be a complex cystic and solid mass due to intervening normal tissue (Fig 11) and was aspirated
twice. One intracystic mass revealed fibrocystic changes and a single adjacent
duct profile with atypical ductal hyperplasia; this mass was excised, showing
only fibrocystic changes. One papilloma
showed moderate enlargement (16 mm,
compared with 10 mm) at 5 years of follow-up, and findings at excision confirmed benign papilloma. Another papilloma was excised due to persistent nipple
discharge.
Solid Masses with Eccentric
Cystic Foci
Of 38 predominantly solid masses with
eccentric cystic foci, seven (18%) proved
malignant (Table 1), including two IDCs
(Fig 12), two invasive and intraductal carcinomas, one invasive lobular carcinoma, one mixed invasive lobular and
ductal carcinoma with associated DCIS,
and one intracystic papillary DCIS (Table
2). Other lesions with this appearance
included fibrocystic changes (n ⫽ 14), fibroadenoma (n ⫽ 11), fat necrosis (n ⫽
1), abscess (n ⫽ 1), and lactating adenoma (n ⫽ 1) (Table 2).
Margin Characteristics
Of 18 malignancies, three (17% [one
intracystic papillary DCIS and two IDCs
grade 3]) were circumscribed round or
oval masses at mammography (Table 4).
Another three (17% [one intracystic papillary DCIS, one medullary carcinoma,
and one IDC grade 3]) were partially obscured. Similarly, five (6%) of 83 sono-
Cystic Lesions of the Breast: Sonographic-Pathologic Correlation
䡠
185
Radiology
TABLE 2
Correlation of Histopathologic Outcome and Sonographic Features for 150 Cystic Lesions
Finding
Simple
Cyst
Complicated
Cyst
8
0
7
1
0
0
0
0
0
0
19 ⫹ 1*
5
4
6
0
1
2
1
0
0
Benign
Cyst
FCC
AM
Abscess
Fibroadenoma
Papilloma
Fat necrosis
Galactocele
Periductal mastitis/cyst rupture
Lactating adenoma
Malignant
IDC
IDC and DCIS
DCIS
ILC
IDC, DCIS, and ILC
Total
0
0
0
0
0
Mass with Thick
Wall and/or Thick
Septations
Intracystic Mass,
Mixed Cystic
and Solid
Solid Mass
with Eccentric
Cystic Foci
Total
2
6
7
0
1
0
0
0
0
0
3
1
1
8
0
0
2
0
1
0
1
3
1
2
0
5
0
1
1
0
1
14
2
1
11
0
1
0
0
1
35 (23)
29 (19)
22 (15)
18 (12)
12 (8)
6 (4)
5 (3.3)
2 (1.3)
2 (1.3)
1 (0.7)
0
0
0
0
0
6
1
0
0
0
1
1
2
0
0
2
2
1
1
1
9 (6)
4 (2.7)
3 (2)
1 (0.7)
1 (0.7)
16
23
18
38
150
Clustered
Microcysts
0
0
0
0
0
38 ⫹ 1*
16
Note.—Data are the number of lesions. Data in parentheses are percentages. AM ⫽ apocrine metaplasia without other fibrocystic changes; FCC ⫽
fibrocystic changes, including fibrosis, sclerosing adenosis, and apocrine metaplasia; ILC ⫽ invasive lobular carcinoma.
* One cyst manifested multiple thin (⬍0.5 mm) septations.
TABLE 3
Results of Follow-up of 150 Cystic Lesions after Initial Aspiration (n ⴝ 55), CNB (n ⴝ 81), or Both (n ⴝ 14)
Follow-up
Sonographic Appearance
None
ⱕ6 Month
Simple cyst (n ⫽ 16)
3 cysts
1 (gone)
Complicated cyst
(n ⫽ 38)
3 cysts,
2 abscesses,
3 other
Cyst with thin septations
(n ⫽ 1)
Clustered microcysts
(n ⫽ 16)
NA
5 (1 recurrent
galactocele,
reaspirated;
4 gone)
NA
2
Mass with thick wall
and/or thick septations
(n ⫽ 23)
1 abscess
Intracystic mass or mixed
cystic and solid
(n ⫽ 18)
Mass with eccentric
cystic foci (n ⫽ 38)
2
All lesions (n ⫽ 150)
12 Month*
ⱖ24 Month†
Surgery
Defined
Standard‡
5 (3 recurred,
2 gone)
8 gone
6 (1 recurred,
5 gone)
14 gone
1 recurred
NA
NA
0
2 (1 gone,
1 stable)
4 (1 gone, 2
decreasing in
size, 1 stable)
NA
12 (75)
1 gone
10 (1 fibrocystic change with atypical cells,
benign; 1 scar after abscess; 1 recurrent
abscess; 7 malignancies)
23 (100)
1 gone
4 gone
1 cyst,
10 other
4 (1 recurrent
abscess,
reaspirated;
3 gone)
4 (1 gone, 3
decreasing
in size)
2 (1 gone,
1 stable)
8 (7 gone, 1
fibrocystic
change
subjected
to another
biopsy)
7 gone
27
18
26
5 (1 gone,
3 stable,
1 fibroadenoma
increasing in
size)
1 cyst recurred as thick-walled cyst
16 (100)
3 (1 recurrent cyst, 1 recurrent fat necrosis,
1 papilloma enlarging due to infarction)
35 (92)
7 (2 papillomas; 1 atypical ductal
hyperplasia at CNB, benign; 4
malignancies)
10 (6 gone, 3 10 (2 large palpable fibroadenomas, 7
malignancies, 1 enlarging lactating
decreasing
adenoma)
in size, 1
stable)
48
31
16 (89)
24 (63)
126 (84)
Note.—Unless otherwise specified, data are the number of lesions. NA ⫽ not applicable.
* Follow-up imaging at least 11 full months after initial diagnosis is considered 12-month follow-up (range, 11–18 months; median, 14 months).
† Follow-up imaging of at least 23 full months after initial diagnosis is considered 24-month follow-up (range, 23– 60 months; median, 32 months).
‡ Pathologic cysts and abscesses with clinical resolution were accepted as were all lesions excised, subjected to another biopsy, or reaspirated with
the same benign result, benign (without atypia) that were gone or decreasing at any follow-up, or stable after 23 full months of follow-up. Data in
parentheses are percentages.
186
䡠
Radiology
䡠
April 2003
Berg et al
Radiology
Figure 1. Complicated cyst with inflammatory changes. Transverse sonogram (10 MHz)
of palpable mass obtained in a 53-year-old
woman demonstrates a well-defined mass
with homogeneous mobile low-level internal
echoes and posterior acoustic enhancement
(arrows). Aspiration yielded benign cyst with
inflammatory changes.
graphically circumscribed oval or round
masses were malignant, and all five were
palpable. Another seven (22%) of 32
sonographically circumscribed lobular
masses were malignant.
DISCUSSION
A sonographically simple cyst (anechoic
with a well-defined imperceptible wall
and posterior acoustic enhancement) can
be dismissed as benign (11), BI-RADS category 2 (12). If the patient is symptomatic with pain or a very large cyst, aspiration can be performed electively. When
the fluid is typical of that of a benign
cyst, such as cloudy yellow or greenish
black fluid, it can be discarded as is generally our practice. We send such fluid for
cytologic examination only at patient request or for patients with a personal history of cancer or an atypical lesion.
Ciatto et al (13) in their series of 6,782
consecutive cysts that were aspirated
found five papillomas, all of which had
bloody fluid. Smith et al (14), in their
analysis of 660 aspirates, and Hindle et al
(15), in an analysis of 689 medical
records, similarly suggest discarding the
fluid unless it is bloody.
The differentiation of a simple cyst
from one with internal echoes or even
solid lesions can be problematic at times,
particularly if the lesion is deep or very
small. With current transducers, most
simple cysts 5 mm or larger can be reliably characterized with standard linearVolume 227
䡠
Number 1
Figure 2. Complicated cyst, apocrine metaplasia. Radial sonogram (7.5 MHz) obtained in
a 43-year-old woman shows mobile debris with
a fluid-debris level (arrow) in a symptomatic cyst
that otherwise met the criteria of simple cyst.
Aspiration yielded apocrine metaplasia.
array high-frequency transducers (center
frequency of at least 10 MHz). Use of
lower-frequency transducers, such as 7.5
MHz or lower, may be necessary for characterization of deeper cysts. Decrease in
dynamic range can improve the ability to
differentiate cystic and solid lesions. The
use of tissue harmonic imaging may improve operator confidence in characterizing a lesion as a cyst, as has been shown
in abdominal sonography (16), and is especially helpful in reducing artifactual
internal echoes (17). Of 25 lesions in this
series suspected to be complicated cysts
that were initially aspirated, 22 (88%) resolved at aspiration and three (two abscesses and one fibrocystic change with
apocrine metaplasia) had remaining
thick walls. Another 13 (34%) of 38 lesions with the appearance of a complicated cyst in retrospect were subjected to
initial diagnosis at CNB because they
were believed to be solid at real-time
evaluation.
Spatial compounding, in which the
sonographic image is derived from the input of multiple off-perpendicular beams,
may also facilitate evaluation of complicated cysts and masses that might be cysts
or solid masses. In an evaluation of 166
cysts and/or complex cysts, spatial compounding increased diagnostic certainty in
77% of lesions (Stavros AT, personal communication, 2002). In 13 masses indeterminate for a cyst or a solid mass, diagnostic
certainty was improved with spatial compounding in 85% of cases (Stavros AT, per-
Figure 3. Cyst with thin septations. Transverse sonogram (7.5 MHz) obtained in a 48year-old woman shows a large cyst with thin
(⬍0.5 mm) septations (arrowheads) that otherwise met the criteria for a simple cyst. This
finding may represent the continuum of the
spectrum from apocrine metaplasia as the
acini fuse. Because it was large and tender, the
cyst was aspirated to complete resolution, and
results of cytologic examination yielded benign cyst contents. This recurred at 1-year follow-up.
sonal communication, 2002). Margin definition is similarly improved with spatial
compounding (18). Spatial compounding
is particularly helpful in decreasing speckle
and other sources of noise; as a result, there
is better definition of internal structure
within masses (18). The improved signalto-noise ratio also facilitates recognition of
small cysts, though posterior enhancement is less apparent with spatial compounding (18). Merritt et al (18) found that
the benefits of real-time spatial compounding decreased with increasing lesion depth.
In the series of Venta et al (10), only
one (0.3%) of 308 complicated cysts
proved malignant, which was a 3-mm
focus of DCIS diagnosed at CNB. Buchberger et al (19) found none of 133 such
lesions malignant, and Kolb et al (20)
found none of 126 such lesions malignant in their series of screening sonography. In our series, none of 38 complicated cysts proved to be malignant. Thus,
cumulatively, only one (0.2%) of 605
complicated cysts has proved to be malignant.
If a complicated cyst remains difficult
to distinguish from a solid mass based on
imaging characteristics alone, then we
must consider the implications of following the mass if indeed it is solid. Of 2,072
breast imaging procedures in our database, three (0.1%) were believed to be
complicated cysts, with aspiration initially attempted, but which proved entirely solid, yielding two fibroadenomas
and one fibrocystic change at CNB. Each
Cystic Lesions of the Breast: Sonographic-Pathologic Correlation
䡠
187
Radiology
Figure 4. Clustered microcysts, apocrine
metaplasia. Radial sonogram (10 MHz) obtained in a 50-year-old woman shows an incidental aggregate of tiny cystic foci (arrowheads) without a discrete solid component. In
our experience, these sonographic features
have been shown to correspond to benign
breast disease, such as apocrine metaplasia, or
fibrocystic changes without apocrine metaplasia. At histopathologic examination of the 14gauge CNB specimen, dilated acini were demonstrated, lined by apocrine metaplastic
epithelium. We now classify such nonpalpable
lesions as probably benign with a 6-month
follow-up.
of these three solid masses were deep at
the chest wall. Stavros et al (5) showed
that nonpalpable, oval or gently lobulated, circumscribed, homogeneously hypoechoic masses with no distinctive posterior features and no suspicious features
had less than 2% risk of malignancy,
though this has not yet been reproduced
at multiple centers. Possibly solid masses
with posterior enhancement (as would be
seen with complicated cysts) have not
been so characterized.
Complex cystic masses with discrete
solid components clearly require biopsy
based on the results of this series. It is
hoped, however, that through the use of
spatial compounding, tissue harmonic
imaging, decrease in the dynamic range,
and increase in operator experience, lesions suspected to be complicated cysts
will be followed up. Multicenter validation of this approach is planned. With
further experience, we may find that
when mobile internal echoes are depicted in such a lesion, classification as
benign may be appropriate. Anecdotally,
we have noted that complicated cysts are
seen in patients with other simple cysts;
an isolated complicated cyst versus a
solid mass may not have the same risk of
malignancy, though this concept also requires validation. A new or enlarging
complicated cyst versus solid mass likely
188
䡠
Radiology
䡠
April 2003
Figure 5. Thick-walled cystic mass, IDC grade
3. Radial sonogram (10 MHz) of a palpable
mass obtained in a 43-year-old woman demonstrates an indistinctly marginated centrally
cystic mass with a thick wall (arrows). Cytologic finding of the sonographically guided
bloody aspirate of the cystic component was
suggestive of malignancy, and CNB of the residual solid component yielded IDC, grade 3.
The lesion resolved after neoadjuvant chemotherapy, and the site was difficult to identify
for excision. Clip placement is advocated if the
lesion is subtle or neoadjuvant chemotherapy
is planned.
merits aspiration as the risk of malignancy may be greater in this context.
Symptomatic complicated cysts generally warrant aspiration. This would include tender or palpable complicated
cysts. Again, as with simple cysts, we examine cytologic specimens only of
bloody fluid. An abscess can appear as a
well-defined cystic lesion with low-level
internal echoes, and abscesses accounted
for six (16%) of 38 complicated cysts in
our series. When an abscess is suspected
clinically at imaging or at inspection of
the fluid, we send the fluid for culture
and Gram staining and initiate a course
of antibiotics that is appropriate for skin
organisms. In the appropriate clinical setting, hematomas, fat necrosis, and galactoceles can appear as complicated cysts.
Management should be predicated on
the basis of patient symptoms.
Of 35 lesions proving to be cysts, seven
(20%) recurred after initial aspiration.
Cysts with a proliferative apocrine lining
have been suggested to be at higher risk
of recurrence than those with flat epithelium (21) and to carry an increased risk of
malignancy (22) that is on the order of
two-fold relative risk (23,24). Indeed,
Bodian et al (24) suggested that the risk
of malignancy was proportional to the
number of cyst aspirations (which in
turn may be related to proliferative
Figure 6. IDC (medullary type) with thick
wall and thick septations. (a) Radial sonogram
(7.5 MHz) of a palpable mass obtained in a
46-year-old woman demonstrates a thickwalled (arrows) cystic mass with thick septations (arrowheads). Posterior acoustic enhancement is present. The margins appear
indistinct. (b) Mammographically, this was a
new, partially circumscribed, and partially indistinctly marginated mass (arrow) in a patient
with multiple bilateral circumscribed masses
due to fibroadenomas and a cyst. Sonographically guided CNB with a 14-gauge needle and
subsequent excision confirmed IDC grade 2,
medullary type.
changes in the cysts), with women who
had undergone more than 10 cyst aspirations at up to a six-fold increased risk of
breast cancer. None of the recurrent cysts
in our series had apocrine lining, and the
two recurrent cysts that were excised
proved to be benign. With the detail apBerg et al
Radiology
Figure 7. Thick-walled cystic mass with thick
septations, IDC grade 3. Transverse sonogram
(10 MHz) obtained in a 35-year-old woman
shows a cystic mass with posterior acoustic
enhancement, thick wall, and thick septations
(arrowheads). Aspiration yielded bloody fluid,
and CNB findings of the residual solid component yielded IDC grade 3.
Figure 8. Thick-walled complicated cyst, abscess. Radial sonogram (10 MHz) obtained in a
48-year-old woman shows a cystic mass with
thick wall (arrows), posterior acoustic enhancement, and internal echoes that were mobile, with fluid-debris level (arrowhead) near
the nipple. The surrounding tissue shows increased echogenicity compatible with edema.
The mass was tender and palpable and was
therefore aspirated to resolution, yielding pus.
parent with use of current sonographic
transducers, it is doubtful that excision is
necessary for a recurrent simple cyst unless it is desired by the patient. The instillation of air at the time of aspiration appears to decrease the risk of recurrence
(25), but it did not prevent recurrence of
a 7-cm postoperative seroma with fat necrosis in our series.
In an overlapping series, we previously
suggested that pure clusters of microcysts
Volume 227
䡠
Number 1
Figure 9. Intracystic mass, intracystic papillary DCIS. Radial sonogram (10 MHz) of a palpable mass obtained in a 36-year-old woman
revealed a well-defined mass with a discrete
solid component (arrow). Sonographically
guided CNB yielded atypical ductal hyperplasia with papillary features. Excisional histopathologic examination revealed intracystic
papillary DCIS. Atypical papillary lesions observed at CNB should be excised due to a 30%
risk of malignancy at excision (39 – 41).
without discrete solid components can
be considered probably benign (26) and
be followed up. Such lesions are often
due to apocrine metaplasia, though fibrocystic changes without apocrine metaplasia can have a similar appearance. It is
possible that larger cysts with thin septations represent the continuum of the
spectrum from apocrine metaplasia to
cysts as acini fuse (26). In our collective
experience (27), we have biopsy proof
(n ⫽ 18) or 2-year follow-up results (n ⫽
48) of 66 lesions prospectively characterized as clustered microcysts with no malignancies, and we now follow such lesions
at 6, 12 and 24 months. Multicenter validation of this approach is required and
planned.
A thick wall or thick septations (ⱖ0.5
mm) in an otherwise cystic lesion without antecedent trauma or evidence of infection should suggest possible malignancy and prompt biopsy. We found
that seven (35%) of 20 lesions without
such relevant history were malignant,
with six (86%) of seven due to high-grade
IDCs. With current transducers, the
sonographic borders of thick-walled cystic lesions are more typically indistinct,
though the mammographic appearance
may be circumscribed. While low-grade
IDC is more often spiculated, circumscribed borders can occur with highgrade malignancies, which were seen in
16% of such lesions in the series of Lamb
et al (28). Of eight high-grade IDCs in our
Figure 10. Intracystic mass with thick septations, infiltrating and intraductal cribriform
carcinoma. Transverse sonogram (7.5 MHz) of
a palpable mass obtained in a 77-year-old
woman shows a complex mixed cystic (C) and
solid (S) mass. Excision showed infiltrating and
intraductal cribriform carcinoma.
series, three (33%) were circumscribed at
sonography. One of these high-grade
cancers had medullary features, and the
others were IDC not otherwise specified.
While aspirates can demonstrate malignant cells, the cystic component of
thick-walled cysts can be necrotic or acellular (and thereby nondiagnostic), and
CNB of the wall or septations is preferred
to provide a specific diagnosis and facilitate definitive treatment. Indeed, the cystic component of high-grade malignancies in this series represented areas of
necrosis. Placement of a clip or an embolization coil marker at the time of sonographic biopsy (29 –31) will facilitate subsequent identification of the lesion if
excision is required. This is particularly
important for lesions that are small (ⱕ7
mm in our experience) or appear to resolve after aspiration or CNB or if neoadjuvant chemotherapy is planned (32).
Abscesses, apocrine metaplasia, and inflamed or ruptured cysts or ducts can also
present as thick-walled cysts. Hematomas
can also have thick walls or thick septations. Fat necrosis can manifest as a
thick-walled cystic lesion or a mixed
complex cystic and solid mass, accounting for seven (23%) of 31 lesions with fat
necrosis in one series (33) and nine (8%)
of 112 in another (34). Short follow-up
(2–3 months until resolution) of a thickwalled cystic lesion may be appropriate
in the proper clinical setting of trauma or
signs of infection. Any enlargement of
such a lesion should prompt biopsy, as
an underlying malignancy can either
bleed due to trauma or cause obstruction
Cystic Lesions of the Breast: Sonographic-Pathologic Correlation
䡠
189
Radiology
TABLE 4
Mammographic and Sonographic Margins of 150 Cystic Lesions
and Rates of Malignancy
Margins
No. of
Lesions
No. of Malignant
Lesions
Mammographic
Circumscribed round or oval
Circumscribed lobular
Circumscribed tubular
Obscured
Microlobulated
Indistinct
Spiculated
Asymmetric density
Not seen
Total with mammographic evaluation
37
19
1
25
4
14
2
7
18
127*
3 (8)
0 (0)
0 (0)
3 (12)
0 (0)
5 (36)
2 (100)
1 (14)
2 (11)
16 (13)*
Sonographic
Circumscribed round or oval
Circumscribed lobular
Circumscribed tubular
Microlobulated
Indistinct
Irregular
Total with sonographic evaluation
83
32
2
17
13
3
150
5 (6)
7 (22)
0 (0)
2 (12)
3 (23)
1 (33)
18 (12)
Note.—Data in parentheses are percentages.
* No mammograms were obtained for 23 lesions, including two malignancies.
of ducts and predispose the patient to
infection.
Both benign and malignant papillary
lesions often manifest as intraductal or
intracystic masses (35–37), and three
(75%) of four malignant intracystic
masses were papillary in this series. Intracystic papillary carcinoma remains uncommon, accounting for only 0.6% of
breast cancer in one series (38) and for
0.8% (four of 500) of breast cancers in
our biopsy population. Caution is appropriate in accepting benign papilloma as a
diagnosis at CNB, because malignancy
and atypia can be focal in a large papilloma. Mammographic- and sonographichistopathologic concordance, including
size concordance, are critical with papillary lesions, as benign papillomas can
also be an incidental finding adjacent to
cancers, with such malignancies reported
in two (17%) of 12 lesions excised after a
CNB diagnosis of benign papilloma in
two series (39,40). Any irregular or indistinctly marginated masses yielding benign papilloma at CNB should be considered discordant and prompt excision
(40). Clearly, atypical papillary lesions
should be excised, with six (30%) of 20
proving malignant in several small series
(39 – 41). In the review of Reynolds (42),
one (50%) of two sclerosed papillomas
proved to be malignant.
Eccentric cystic foci can be due to dilated ducts, acini, or necrosis. Fibroadenomas rarely can have eccentric cystic
foci, as was first described by Jackson et al
190
䡠
Radiology
䡠
April 2003
(43). Only 12 (2.9%) of 407 fibroadenomas in our database had cystic foci. The
presence of cystic foci in a mass that is
otherwise consistent with a fibroadenoma may suggest a possible phyllodes
tumor, though such tumors are rare. Cystic foci were seen in seven (23%) of 30
phyllodes tumors in the series of Liberman et al (44) and were more common in
malignant phyllodes tumors. Apocrine
metaplasia can coexist with a variety of
benign lesions, including fibroadenoma,
and be evident as eccentric cystic foci
(26). Malignancies with eccentric cystic
foci had no particular distinguishing features in our series, with low- and highgrade IDC, invasive lobular carcinoma,
and intraductal carcinoma rarely having
this appearance.
The margin characteristics of cystic lesions also merit discussion. For nonpalpable mammographically circumscribed
masses, Sickles (45,46) and Varas et al
(47) have shown that the risk of malignancy is less than 2% and that such lesions can be followed up. Indeed, none of
the 29 nonpalpable sonographically circumscribed round or oval lesions were
malignant in our series. Of the 54 palpable circumscribed round or oval lesions,
five (9%) proved to be malignant. Those
five malignancies were seen as intracystic
masses (n ⫽ 2), thick-walled cystic masses
(n ⫽ 2), and a predominantly solid mass
with eccentric cystic foci (n ⫽ 1). All
sonographically circumscribed lobulated
masses that were malignant in this series
Figure 11. Complex mass, galactocele. Transverse sonogram (7.5 MHz) of palpable mass
occupying most of the breast obtained in a
18-year-old woman shows a complex cystic (C)
and solid (S) mass. Aspiration was performed
for symptomatic relief, yielding 250 mL of
breast milk. The solid components were due to
intervening normal breast tissue with extensive galactocele.
Figure 12. Predominantly solid mass with eccentric cystic spaces, IDC grade 3. Transverse
sonogram (10 MHz) of a palpable mass obtained in a 36-year-old woman with prior contralateral cancer 2 years earlier shows lobulated
hypoechoic mass with eccentric cystic spaces
(arrowheads). Findings of fine-needle aspiration (at an outside institution) showed atypical
cells but were nondiagnostic. Gadolinium-enhanced breast magnetic resonance (MR) imaging demonstrated a rim-enhancing mass that
was highly suggestive of malignancy. On the
basis of MR imaging findings, the patient was
referred for excision and sentinel node biopsy,
which revealed IDC grade 3.
were complex cystic and solid masses. As
has previously been suggested (48), sonography may be helpful in identifying those
circumscribed masses that merit biopsy.
In conclusion, sonographically simple
cysts can be dismissed as benign. On the
Berg et al
Radiology
basis of the collective experience of this
series and of the literature, the majority
of incidental nonpalpable complicated
cysts containing low-level echoes or fluid-debris levels may be be classified as
probably benign, though further study is
warranted and planned. Symptomatic
complicated cysts should be managed on
clinical grounds and generally warrant
aspiration, with abscess, hematoma, fat
necrosis, and galactocele in the differential diagnosis. In this series, all clustered
microcysts were benign, though further
study is required. Complex cystic breast
masses with thick walls and thick septations, intracystic masses, masses with
mixed cystic and solid components, and
solid masses with eccentric cystic foci
merit biopsy, with 18 (23%) of 79 of such
complex cystic lesions proving to be malignant in our series.
13.
14.
15.
16.
17.
18.
19.
References
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Bassett LW. Imaging of breast masses. Radiol
Clin North Am 2000; 38:669 – 691.
Parker SH, Jobe WE, Dennis MA, et al. USguided automated large-core breast biopsy.
Radiology 1993; 187:507–511.
Liberman L, Feng TL, Dershaw DD, Morris
EA, Abramson AF. US-guided core breast biopsy: use and cost-effectiveness. Radiology
1998; 208:717–723.
Pisano ED, Fajardo LL, Caudry DJ, et al. Fineneedle aspiration biopsy of nonpalpable
breast lesions in a multicenter clinical trial:
results from the radiologic diagnostic oncology group V. Radiology 2001; 219:785–792.
Stavros AT, Thickman D, Rapp CL, Dennis
MA, Parker SH, Sisney GA. Solid breast nodules: use of sonography to distinguish between benign and malignant lesions. Radiology 1995; 196:123–134.
Baker JA, Kornguth PJ, Soo MS, Walsh R,
Mengoni P. Sonography of solid breast lesions: observer variability of lesion description and assessment. AJR Am J Roentgenol
1999; 172:1621–1625.
Rahbar G, Sie AC, Hansen GC, et al. Benign
versus malignant solid breast masses: US differentiation. Radiology 1999; 213:889 – 894.
Mendelson EB, Berg WA, Merritt CR. Toward
a standardized breast ultrasound lexicon, BIRADS: ultrasound. Semin Roentgenol 2001;
36:217–225.
Omori LM, Hisa N, Ohkuma K, et al. Breast
masses with mixed cystic-solid sonographic
appearance. J Clin Ultrasound 1993; 21:489 –
495.
Venta LA, Kim JP, Pelloski CE, Morrow M.
Management of complex breast cysts. AJR
Am J Roentgenol 1999; 173:1331–1336.
Hilton SV, Leopold GR, Olson LK, Willson
SA. Real-time breast sonography: application
in 300 consecutive patients. AJR Am J Roentgenol 1986; 147:479 – 486.
American College of Radiology. Breast Imaging Reporting and Data System. 3rd ed. Reston, Va: American College of Radiology,
1998.
Volume 227
䡠
Number 1
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
Ciatto S, Cariaggi P, Bulgaresi P. The value of
routine cytologic examination of breast cyst
fluids. Acta Cytol 1987; 31:301–304.
Smith DN, Kaelin CM, Korbin CD, Ko W,
Meyer JE, Carter GR. Impalpable breast cysts:
utility of cytologic examination of fluid obtained with radiologically guided aspiration.
Radiology 1997; 204:149 –151.
Hindle WH, Arias RD, Florentine B, Whang J.
Lack of utility in clinical practice of cytologic
examination of nonbloody cyst fluid from
palpable breast cysts. Am J Obstet Gynecol
2000; 182:1300 –1305.
Choudhry S, Gorman B, Charboneau JW, et
al. Comparison of tissue harmonic imaging
with conventional US in abdominal disease.
RadioGraphics 2000; 20:1127–1135.
Sklair-Levy M, Muradali D, Kulkarni S. Linear
transducer harmonic imaging: improved
characterization of breast cysts compared to
conventional sonography (abstr). AJR Am J
Roentgenol 2001; 176(S):6 –7.
Merritt C, Piccoli C, Forsberg F, Wilkes A,
Cavanaugh B, Lee S. Real-time spatial compound imaging of the breast: clinical evaluation of masses (abstr). Radiology 2000;
217(P):491– 492.
Buchberger W, DeKoekkoek-Doll P, Springer
P, Obrist P, Dunser M. Incidental findings on
sonography of the breast: clinical significance and diagnostic workup. AJR Am J
Roentgenol 1999; 173:921–927.
Kolb TM, Lichy J, Newhouse JH. Occult cancer in women with dense breasts: detection
with screening US— diagnostic yield and tumor
characteristics.
Radiology
1998;
207:191–199.
Dixon JM, Scott WN, Miller WR. Natural history of cystic disease: the importance of cyst
type. Br J Surg 1985; 72:190 –192.
Dixon JM, Lumsden AB, Miller WR. The relationship of cyst type to risk factors for
breast cancer and the subsequent development of breast cancer in patients with breast
cystic disease. Eur J Cancer Clin Oncol 1985;
21:1047–1050.
Bundred NJ, West RR, Dowd JO, Mansel RE,
Hughes LE. Is there an increased risk of breast
cancer in women who have had a breast cyst
aspirated? Br J Cancer 1991; 64:953–955.
Bodian CA, Lattes R, Perzin KH. The epidemiology of gross cystic disease of the breast
confirmed by biopsy or by aspiration of cyst
fluid. Cancer Detect Prev 1992; 16:7–15.
Gizienski TA, Harvey JA, Sobel AH. Breast
cyst recurrence after postaspiration injection
of air. Breast J 2002; 8:34 –37.
Warner JK, Kumar D, Berg WA. Apocrine
metaplasia: mammographic and sonographic appearances. AJR Am J Roentgenol
1998; 170:1375–1379.
Berg WA. Can clusters of microcysts appropriately be followed? (abstr). Radiology 2002;
224(P):368.
Lamb PM, Perry NM, Vinnicombe SJ, Wells
CA. Correlation between ultrasound characteristics, mammographic findings and histological grade in patients with invasive ductal
carcinoma of the breast. Clin Radiol 2000;
55:40 – 44.
Phillips SW, Gabriel H, Comstock CE, Venta
LA. Sonographically guided metallic clip
placement after core needle biopsy of the
breast. AJR Am J Roentgenol 2000;
175:1353–1355.
Guenin MA. Clip placement during sono-
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
graphically guided large-core breast biopsy
for mammographic-sonographic correlation.
AJR Am J Roentgenol 2000; 175:1053–1055.
Kopans DB. Clip placement during sonographically guided breast biopsy. AJR Am J
Roentgenol 2001; 176:1076 –1077.
Reynolds HE, Lesnefsky MH, Jackson VP. Tumor marking before primary chemotherapy
for breast cancer. AJR Am J Roentgenol 1999;
173:919 –920.
Soo MS, Kornguth PJ, Hertzberg BS. Fat necrosis in the breast: sonographic features. Radiology 1998; 206:261–269.
Bilgen IG, Ustun EE, Memis A. Fat necrosis of
the breast: clinical, mammographic and
sonographic features. Eur J Radiol 2001; 39:
92–99.
Reuter K, D’Orsi CJ, Reale F. Intracystic carcinoma of the breast: the role of ultrasonography. Radiology 1984; 153:233–234.
Soo MS, Williford ME, Walsh R, Bentley RC,
Kornguth PJ. Papillary carcinoma of the
breast: imaging findings. AJR Am J Roentgenol 1995; 164:321–326.
Liberman L, Feng TL, Susnik B. Case 35: intracystic papillary carcinoma with invasion.
Radiology 2001; 219:781–784.
Framarino dei Malatesta ML, Piccioni MG,
Felici A, et al. Intracystic carcinoma of the
breast: our experience. Eur J Gynaecol Oncol
1992; 13:40 – 44.
Philpotts LE, Shaheen NA, Jain KS, Carter D,
Lee CH. Uncommon high-risk lesions of the
breast diagnosed at stereotactic core-needle
biopsy: clinical importance. Radiology 2000;
216:831– 837.
Mercado CL, Hamele-Bena D, Singer C, et al.
Papillary lesions of the breast: evaluation
with stereotactic directional vacuum-assisted
biopsy. Radiology 2001; 221:650 – 655.
Liberman L, Bracero N, Vuolo MA, et al. Percutaneous large-core biopsy of papillary
breast lesions. AJR Am J Roentgenol 1999;
172:331–337.
Reynolds HE. Core needle biopsy of challenging benign breast conditions: a comprehensive literature review. AJR Am J Roentgenol 2000; 174:1245–1250.
Jackson VP, Rothschild PA, Kreipke DL, Mail
JT, Holden RW. The spectrum of sonographic findings of fibroadenoma of the
breast. Invest Radiol 1986; 21:34 – 40.
Liberman L, Bonaccio E, Hamele-Bena D,
Abramson AF, Cohen MA, Dershaw DD. Benign and malignant phyllodes tumors: mammographic and sonographic findings. Radiology 1996; 198:121–124.
Sickles EA. Periodic mammographic follow-up of probably benign lesions: results in
3184 consecutive cases. Radiology 1991; 179:
463– 468.
Sickles EA. Nonpalpable, circumscribed,
noncalcified solid breast masses: likelihood
of malignancy based on lesion size and age
of patient. Radiology 1994; 192:439 – 442.
Varas X, Leborgne F, Leborgne JH. Nonpalpable, probably benign lesions: role of follow-up mammography. Radiology 1992;
184:409 – 414.
Taylor KJW, Merritt C, Piccoli C, et al. Ultrasound as a complement to mammography
and breast examination to characterize
breast masses. Ultrasound Med Biol 2002;
28:1–18.
Cystic Lesions of the Breast: Sonographic-Pathologic Correlation
䡠
191