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Chapter 6
137
The spleen and lymphatic system
CHAPTER CONTENTS
The spleen—normal appearances
and technique 137
Splenomegaly 139
Splenunculi 139
Malignant splenic disease 141
Lymphoma 141
Metastases 141
Leukaemia 142
Benign splenic conditions 143
Cysts 144
Haemangioma 145
Abscess 145
Calcification 145
Haemolytic anaemia 146
Vascular abnormalities of the spleen 146
Splenic trauma 148
Lymphatics 148
THE SPLEEN—NORMAL APPEARANCES
AND TECHNIQUE
The spleen normally lies posterior to the splenic
flexure and stomach, making an anterior approach
almost invariably unsuccessful due to overlying
bowel gas. The spleen should therefore be
approached from the left lateral aspect: coronal and
transverse sections may be obtained with the
patient supine by using an intercostal approach.
Gentle respiration is frequently more successful
than deep inspiration, as the latter brings the lung
bases downwards and may obscure a small spleen
altogether.
Lying the patient decubitus, left side raised, may
also be successful but sometimes has the effect of
causing the gas-filled bowel loops to rise to the left
flank, once again obscuring the spleen. A slightly
posterior approach may overcome this.
Ultrasound appearances
The normal spleen has a fine, homogeneous texture,
with smooth margins and a pointed inferior
edge. It has similar echogenicity to the liver but
may be slightly hypo- or hyperechoic in some
subjects.
Sound attenuation through the spleen is less
than that through the liver, requiring the operator
to ‘flatten’ the time gain compensation controls in
order to maintain an even level of echoes
throughout the organ. The main splenic artery
and vein and their branches may be demonstrated
at the splenic hilum (Fig. 6.1).