Diagnostic ultrasound ( PDFDrive )

148 PART II Abdominal and Pelvic Sonography
A
B
C
FIG. 5.10 Primary Congenital (Epidermoid) Cyst. (A) Coronal
extended–ield of view image shows a large, 11-cm cystic lesion
that contains heterogeneous material in asymptomatic patient.
A small rim of spleen is noted inferior and lateral to the cyst. (B)
Transverse magniied ultrasound image shows internal echoes
from cholesterol crystals and debris mimicking a solid lesion. (C)
Computed tomography scan after intravenous contrast demonstrates
the large cyst indenting the stomach.
Endothelial-lined cysts include lymphangiomas and cystic
hemangiomas. 41,42 Lymphangiomas have been described as
multiple cysts of varying size, ranging from a few millimeters
to several centimeters, divided by thin septa. 43 Hemangiomas
with cystic spaces of variable size have been reported.
Cystic metastases to the spleen are typically seen in patients
with widespread metastatic disease, such as ovarian or colon
carcinoma. Occasionally, necrotic metastases mimic a cystic
lesion.
he most common causes of splenic abscess are endocarditis,
septicemia, and trauma. 44 Splenic pyogenic abscesses may have
an appearance similar to that of simple cysts, but the diagnosis
is typically made in conjunction with the clinical indings. he
presence of gas indicates an infectious cause. Gas may cause a
confusing picture if only a small, curvilinear or punctate hyperechoic
focus is seen. he presence of a reverberation artifact
(dirty shadowing) indicates the presence of gas (Fig. 5.14).
However, the sonographic indings of a pyogenic abscess are
variable, and in indeterminate cases, aspiration is useful for
diagnosis. 45 Percutaneous catheter drainage can be used as a safe
and successful treatment option. 46
Nodular Splenic Lesions
Nodular lesions are oten multiple and can be subdivided into
micronodular (<1 cm) and nodular (1-3 cm). If splenic nodules
are present in a patient with a known diagnosis such as lymphoma,
tuberculosis, or sarcoidosis, these nodules likely represent the
same disease. However, if no diagnosis has been established and
the splenic nodules are an isolated inding, the diagnosis is rarely
made on the imaging features alone. he most common causes
of splenic nodules include infection (e.g., mycobacteria, histoplasmosis),
sarcoidosis, and malignancy (e.g., lymphoma,
metastases). Other, less common causes of splenic nodular lesions
with similar imaging indings include Gamna-Gandy bodies,