Diagnostic ultrasound ( PDFDrive )

782 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
A
B
FIG. 21.32 Complex Cystic and Solid Mass. (A) This mass has both solid and cystic components. Color Doppler demonstrates that the thick
internal septations are highly vascular, suggesting they represent solid material rather than internal debris, increasing the probability of malignancy.
(B) Also note the extension of the solid component beyond the margin of the mass (arrow), most consistent with a malignant process.
solid or thick luid, additional nonmalignant diferential considerations
for a cystic and solid appearing mass include
hematoma, fat necrosis, abscess, or galactocele. Given the
increased probability for malignancy for complex cystic and solid
masses, they should be classiied as BI-RADS 4 or BI-RADS 5
lesions and biopsy should be performed. When the mass is
sampled, special attention should be paid to the solid
component.
Papillary Lesions. Complex cystic and solid masses may
involve intracystic or intraductal papillary lesions. Sonography
does not distinguish benign from malignant intraductal or
intracystic masses as efectively as it does for purely solid nodules
because of the direction of invasion. Invasion arising from solid
nodules is outwardly directed, greatly afecting the shape and
the surface characteristics of the lesion. However, invasion arising
from intracystic or intraductal lesions is inwardly directed, into
the ibrovascular stalk of the lesion. As a result, the surface
characteristics and shape are not distorted, making it more
challenging to use sonographic descriptors to identify an abnormality.
Any intracystic or intraductal papillary lesion with solid
components should be characterized as BI-RADS 4a or higher
and undergo histologic evaluation.
Findings that are suspicious for true intracystic or intraductal
papillary lesions include thick isoechoic septations, mural nodules,
a Doppler-demonstrable vascular stalk within a thick septation,
and clustered complex microcysts. hick, isoechoic septations
are suspicious for intracystic papilloma or intracystic carcinoma
(Fig. 21.33A), whereas thin echogenic septations merely represent
ibrocystic change and the intact walls between multiple ductules
with severe cystic dilation within an individual TDLU (Fig.
21.33B). Most mural nodules are caused by PAM, which is part
of the benign FCC spectrum, or are pseudonodules caused by
tumefactive sludge or lipid layers rather than papillomas or
intracystic papillary carcinomas. Suspicious mural nodules
demonstrate loss of the thin echogenic outer cyst wall along
their points of attachment, extension beyond the circular or oval
shape of the cyst into surrounding ducts (Fig. 21.34A), or angular
margins at the point of attachment. Mural nodules that are caused
by PAM remain conined within the circular or round shape of
the cyst in which they lie and do not disrupt the thin, echogenic
outer cyst wall (Fig. 21.34B). Regardless, biopsy of all these masses
should be performed to ensure there is no malignancy present.
Papillomas and intracystic carcinomas are generally vascular
and tend to develop easily demonstrable and prominent vascular
stalks (Fig. 21.35A, Video 21.4), whereas mural nodules and
thick internal septations caused by lorid PAM rarely develop
vascular stalks (Fig. 21.35B). Papillomas and intracystic carcinomas
frequently undergo hemorrhagic infarction that can
obscure vascularity. Most benign papillomas have a single feeding
vessel, whereas malignant intracystic papillary lesions tend to
incite the formation of multiple feeding vessels. 49 Clustered
microcysts most frequently merely represent FCC and apocrine
metaplasia 50 (Fig. 21.36A), but high–nuclear-grade micropapillary
DCIS can also appear as clustered microcysts (Fig. 21.36B). he
gray-scale appearances of microcysts caused by apocrine metaplasia
and micropapillary DCIS can be virtually indistinguishable.
However, clustered microcysts caused by micropapillary DCIS
are usually vascular on color Doppler sonography, whereas
microcysts caused by apocrine metaplasia, like mural
nodules caused by apocrine metaplasia, are usually avascular on
color Doppler ultrasound assessment (Fig. 21.36C). If even one
suspicious inding is present, the cystic lesion should be characterized
as BI-RADS 4a or higher and should be evaluated
histologically. 45
Inlammation and Infection. Nonsimple cysts may be caused
by inlammation and/or infection. he indings that are suspicious
for acute inlammation or infection are (1) uniform isoechoic
thickening of the cyst wall, (2) luid-debris levels (tumefactive
sludge or layered pus), and (3) inlammatory hyperemia of cyst
wall and surrounding tissues. Usually, all three indings coexist
(Fig. 21.37A). Uniform isoechoic thickening is typical of inlammation,
not tumor, so this inding does not raise much concern
about malignancy. Debris levels can be shown to shit to the
dependent portion of complex cysts when the patient is placed