Diagnostic ultrasound ( PDFDrive )

CHAPTER 5 The Spleen 153
A
B
FIG. 5.18 Calciied Granulomas in a Patient With Sarcoidosis. (A) Multiple tiny bright foci throughout the spleen, some demonstrating
posterior shadowing. (B) Computed tomography scan after intravenous contrast shows multiple small parenchymal calciications throughout the
spleen.
FIG. 5.19 Splenic Artery Calciications. Central splenic artery calciications
in a patient on peritoneal dialysis.
sonographic patterns of lymphomatous involvement of the spleen
have been described, 53 corresponding with the pathologic indings:
(1) difuse involvement, typically an enlarged spleen with a normal
echotexture or patchy inhomogeneity; (2) focal small (<3 cm)
hypoechoic nodular lesions; (3) focal large (>3 cm) nodular
lesions; and (4) bulky solid mass lesions (Fig. 5.21). Focal lesions
in lymphoma are typically hypoechoic and hypovascular. 31
Occasionally, ater central necrosis with subsequent liquefaction,
lesions may present as anechoic cysts or mimic an abscess. 54
Hyperechoic lesions are uncommon.
Primary splenic malignancies include primary lymphoma,
angiosarcoma, and hemangiopericytoma. Isolated (primary)
lymphoma of the spleen is rare and is encountered in less than
1% of all patients with lymphoma. It typically represents Hodgkin
disease. 52 Angiosarcoma is a rare primary malignant vascular
neoplasm of the spleen with a very poor prognosis. Sonographic
indings include a heterogeneous echotexture, complex mass or
masses, and splenomegaly (Fig. 5.22). Increased Doppler low
may be seen in the solid components of the tumor. 55,56 Hemangiopericytoma
is a very rare tumor that may arise in the spleen
with variable malignant potential. On ultrasound, it may appear
as a hypoechoic vascular mass distinct from the surrounding
splenic parenchyma. 40
Metastases to the spleen are relatively rare and generally occur
as a late phenomenon. hey are typically seen in patients with
widespread metastatic disease rather than as a presenting feature. 57
Isolated metastases to the spleen are very uncommon. Splenic
metastases are relatively frequent in malignant melanoma but
can be encountered in any metastatic disease, including carcinoma
of the lung, breast, ovary, stomach, or colon and in Kaposi
sarcoma. 58 Metastases are usually hypoechoic but may be echogenic,
heterogeneous, or even cystic 1 (Fig. 5.23).
Benign Lesions. Hemangioma is the most common primary
benign neoplasm of the spleen; incidence ranges from 0.3% to
14% in autopsy series. 59 Hemangiomas are usually isolated
phenomena but can be part of a generalized condition, such as
hemangiomatosis or Klippel-Trenaunay-Weber syndrome. 60,61
he lesions oten have a well-deined echogenic appearance similar
to the typical appearance of hemangiomas in the liver, but this
appearance is seen much less frequently in the spleen than in
the liver (Fig. 5.24). Lesions of mixed echogenicity, with cystic
spaces of variable sizes and foci of calciication, have also been
reported. 41,59
Other benign tumors of the spleen are rare and include
hamartomas, littoral cell angioma, sclerosing angiomatoid nodular
transformation (SANT), and inlammatory pseudotumor.
Hamartomas are typically well-deined, homogeneous, isoechoic
to mildly hypoechoic or hyperechoic lesions 62 (Fig. 5.25). Hamartomas
may contain cystic areas or coarse calciications, and