Diagnostic ultrasound ( PDFDrive )

CHAPTER 21 The Breast 779
A
B
FIG. 21.27 Lipid Cyst. Mammographic spot compression views can more accurately characterize lipid cysts than sonography. On ultrasound
images, (A) lesions that appear to be classic benign lipid cysts on mammography often have suspicious features, such as (B) thick irregular wall,
thick isoechoic septations, and mural nodules. These sonographically suspicious features are typical of chronic hematomas, from which most lipid
cysts arise.
cysts originate in chronic seromas or hematomas, which oten
manifest such indings. However, the suspicious sonographic
indings in lipid cysts are avascular, unlike those in cysts containing
true papillary lesions. Nevertheless, lipid cysts frequently
appear more worrisome sonographically than on spot compression
mammograms. hus, when sonographic and mammographic
indings are discordant, we rely more on the mammographic
indings in this subset of patients, unless color Doppler ultrasound
shows internal vascularity.
Eggshell calciications are benign mammographic indings
that have been applied directly to sonography. In general, eggshell
calciications are so deinitively benign on mammography that
they do not require sonographic assessment (Fig. 21.28A-B).
Occasionally they will be seen on sonography in a patient who
has not had mammography or for whom the mammograms are
not available. Punctate calciications that occur within the normal
thin, echogenic cyst wall represent incomplete eggshell calciications
and therefore can be considered BI-RADS 2 sonographic
indings (Fig. 21.28C). In such cases the sonographic indings
are more deinitively benign than the mammographic indings.
Calciications that are suspended within the lumen of a cyst
cannot be characterized as BI-RADS 2. In most cases they occur
with papillary apocrine metaplasia (PAM), but they can also
occur in DCIS (Fig. 21.28D).
Clustered macrocysts are identical to thinly septated cysts
(Fig. 21.29). he septations represent the residual walls of
individual, cystically dilated ductules within an individual TDLU.
Each cystically dilated ductule can be thought of as a simple
cyst; a thinly septated cyst is typically a cluster of simple cysts,
each having BI-RADS 2 characteristics.
Cysts of skin origin are benign and usually represent sebaceous
cysts or epidermal inclusion cysts. Sebaceous cysts have
three typical appearances: (1) a complex or solid-appearing lesion
that lies entirely within the skin (Fig. 21.30); (2) a complicated
cyst that lies mainly within the subcutaneous tissues but has
clawlike hyperechoic skin wrapped around it (Fig. 21.30B); and
(3) a lesion that lies entirely within the subcutaneous fat but has
an associated, abnormally hypoechoic, thickened inlamed gland
neck that courses through the skin (Fig. 21.30C). he gland neck
is obliquely oriented and is oten better demonstrated by heeling
or toeing the transducer to change the angle of incidence. Because
cysts of skin origin are so supericial in location, optimal demonstration
of one of these three patterns usually requires that
an acoustic standof be used.
Foam cysts are cysts whose lumens are completely illed with
low-level echoes (Fig. 21.31A). Other names include gel cysts
and inspissated cysts. he foam cyst appearance can actually
represent a spectrum of lesions, from those completely illed
with PAM to those that contain only echogenic proteinaceous
debris or lipid material. 48 Others may contain mixtures of PAM
and proteinaceous or fatty debris. hese lesions have sonographic
features that overlap with those of ibroadenomas, and in about
3% of cases it is not possible to determine with certainty whether
the lesion is cystic or solid. In this scenario, the clinician should
characterize the mass using BI-RADS descriptors and make a
recommendation based on the most suspicious inding. If the
sonographic features suggest a low probability for malignancy,
this mass—whether cystic with low-level echoes or solid—can
be followed and classiied as BI-RADS 3. Otherwise, sampling
should be performed. Aspiration may be attempted irst, followed
by core biopsy if unsuccessful. When the internal echoes are all
caused by PAM, the lesion cannot be aspirated. When the lesion
is illed with proteinaceous or fatty debris, it can be completely
aspirated. If partially illed with PAM, the lesion will be only
partially aspirated. In this case, core biopsy of the residual material
or additional short-term follow-up is recommended.