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THE SPLEEN AND LYMPHATIC SYSTEM 141
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homogeneous, intrasplenic ‘mass’ when the
spleen is viewed coronally (Fig. 6.2D). A
transverse scan at the epigastrium should
demonstrate the extent of left hepatic
enlargement and confirm its relationship to the
spleen.
Splenunculi may be mistaken for enlarged
lymph nodes at the splenic hilum. Colour
Doppler can confirm the vascular supply is
shared by the spleen.
The normal tail of pancreas may mimic a
perisplenic mass.
A left adrenal mass, or upper pole renal mass,
may indent the spleen making it difficult to
establish the origin of the mass.
MALIGNANT SPLENIC DISEASE
Lymphoma
Lymphoma is the most common malignant disease
affecting the spleen. Lymphomas comprise a number
of diseases, all malignant, which affect the lymphocytes.
Malignant cells can infiltrate the spleen,
lymph nodes, bone marrow and thymus and can
also involve the liver, gastrointestinal tract, kidney
and other organs. Approximately 3% of malignant
diseases are lymphomas.
Splenic involvement may be found in up to 60%
of lymphomas as a result of dissemination of the
disease. Primary splenic lymphoma, limited to the
spleen, is very rare, and accounts for less than 1%
of lymphomas. There are two main groups:
Hodgkin’s and non-Hodgkin’s lymphomas.
Clinical features and management
Patients may present with a range of non-specific
symptoms which include lymph node enlargement,
anaemia, general fatigue, weight loss, fever, sweating
and infections associated with decreased immunity.
If the disease has spread to other organs, these
may produce symptoms related to the organs in
question.
Prognosis depends upon the type of the disease,
which must be determined histologically, and its
stage. Both ultrasound and CT may be used in
staging: ultrasound demonstrates splenic involvement
with greater sensitivity than CT, and CT is
superior in demonstrating para-aortic and iliac
lymph nodes. 2 Bone scintigraphy and MRI are further
supplementary techniques in staging.
Depending upon the type of lymphoma,
chemotherapy regimes may be successful and, if
not curative, can cause remission for lengthy periods.
High-grade types of lymphoma are particularly
aggressive with a poor survival rate.
Ultrasound appearances
The range of possible ultrasound appearances in
lymphoma is varied (Fig. 6.3). In many cases the
spleen is not enlarged and shows no acoustic
abnormality. In a study of 61 patients with
Hodgkin’s disease involving the spleen, the organ
was usually normal in size and showed no acoustic
abnormality in 46% of cases. 3
Lymphoma may produce a diffuse splenic
enlargement with normal, hypo- or hyperechogenicity.
Focal lesions may be present in up to
16% of lymphomas. 4,5 They tend to be hypoechoic
and may be single or multiple, and of varying sizes.
In larger lesions the margins may be ill-defined and
the echo contents vary from almost anechoic to
heterogeneous, often with increased through-transmission.
In such cases, they may be similar in
appearance to cysts, however, the well-defined capsule
is absent in lymphoma, which has a more indistinct
margin. 6 Smaller lesions may be hyperechoic
or mixed. Tiny lymphomatous foci may affect the
entire spleen, making it appear coarse in texture.
Lymphadenopathy may be present elsewhere in
the abdomen. If other organs, such as the kidney
or liver, are affected, the appearances of mass
lesions vary but are commonly echo-poor or of
mixed echo pattern.
A differential diagnosis of metastases should be
considered in the presence of multiple solid hypoechoic
splenic lesions, but most cases are due to
lymphoma. 7
Metastases
Metastatic deposits occur in the spleen much less
commonly than in the liver. Autopsy reports an
incidence of around 10%, although a proportion of