SPLENOMEGALY SPLENUNCULI SCANNING
Category: Diagnostic Radiology
Abstract : Splenomegaly Enlargement of the spleen is a highly non-specific sign
associated with numerous conditions, the most common being infection, portal
hypertension, haematological disorders and neoplastic conditions. As with the
liver, measurement of splenic volume is usually considered inaccurate due to
variations in shape, and not reproducible. However, the length of the spleen is
an ade
Splenomegaly
Enlargement of the spleen is a highly non-specific sign
associated with numerous conditions, the most common being infection, portal
hypertension, haematological disorders and neoplastic conditions. As with the
liver, measurement of splenic volume is usually considered inaccurate due to
variations in shape, and not reproducible.
However, the length of the spleen is
an adequate indicator of size for most purposes and provides a useful baseline
for monitoring changes in disease status. The length of the normal adult spleen
is less than 12 cm.
The spleen enlarges downwards and medially. Its
inferior margin becomes rounded, rather than pointed, and may extend below the
left kidney. Although the aetiology of splenomegaly may not be obvious on
ultrasound, the causes can be narrowed down by considering the clinical picture
and by identifying other relevant appearances in the abdomen. Splenomegaly due
to portal hypertension, for example, is frequently accompanied by other
associated pathology such as cirrhotic liver changes, varices or
ascites.
Examples of causes of splenomegaly
● Portal hypertension
●
Acute or chronic systemic infection, e.g. hepatitis, AIDS, infectious
mononucleosis, sepsis
● Haemolytic anaemia, sickle cell disease,
thalassaemia, pernicious anaemia, spherocytosis
● Malignancy—leukaemia,
Hodgkin’s and non-Hodgkin’s lymphoma, myeloproliferative disorders
● Storage
disorders
● Immunological diseases
Splenunculi
In around 10% of the
population, a small accessory spleen, or splenunculus, may be located at the
splenic hilum. These small, well-defined ectopic nodules of splenic tissue
rarely exceed 2 cm in diameter. Splenunculi enlarge under the same circumstances
as those which cause splenomegaly and may also hypertrophy in postsplenectomy
patients. The importance of recognizing these lies in differentiating them from
lymph nodes, left adrenal nodules or masses in the tail of pancreas. Colour
Doppler may identify the vascular supply as being common to the main
spleen.
Pitfalls in scanning the spleen
● In hepatomegaly, the left
lobe of liver may extend across the abdomen, indenting the spleen. This can give
the appearance of a homogeneous, intrasplenic ‘mass’ when the spleen is viewed
coronally. 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.
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