Ebook Diagnostic pediatric ultrasound: Part 2

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Chapter 10
Spleen

10.1

Normal Anatomy and Variants

324

10.2

Pathology

332

10.3

Acknowledgements

354

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10 Spleen
Samuel Stafrace
The spleen is a pyramid-shaped organ normally located in the

left upper quadrant. It forms part of and is the largest organ
within the lymphoproliferative system. It plays a major role in
the immune system and also functions as a filter of damaged
and abnormal red blood cells.
Imaging of the spleen starts and often rests very much with
ultrasound. Depending on a child’s age, this organ can be
imaged with transducers of different frequencies. Exquisite
images can be obtained with higher frequency, particularly in
the younger child.
Requests for examining this organ are often related to a clinically palpable increase in its size. Other frequent indications are
for the assessment of hematologic conditions and in the setting
of trauma. The assessment and measurement of the spleen are
part of the normal ultrasound examination of the pediatric
abdomen.
This chapter describes the normal appearances, variants,
and most common pathologies of the spleen as seen with
ultrasound.

10.1 Normal Anatomy and
Variants
10.1.1 Embryology
The spleen begins to develop at the fifth week of fetal life. It
develops from multiple cellular nests located within the dorsal
mesogastrium (▶ Fig. 10.1). Symmetrical splenic precursors are
thought to exist with preferential development of the left sided
splenic tissue. These cellular nests eventually fuse to form a single organ. The small anterior notch often seen in the anterior
aspect of the spleen is thought to result from this fusion process. The presence of accessory small spleens (splenunculi),
seen in about 10% of normal individuals, results from
incomplete fusion of all the splenic tissue into one organ.

Given its embryonal development in the dorsal mesogastrium, the final location of splenic tissue is very much dependent on normal situs and normal bowel rotation. At 8 weeks’
gestation, the liver rotates to the right, and the stomach and
spleen rotate to the left. The peritoneal reflections between
these organs follow their rotational movement.

10.1.2 Anatomical Considerations
The final anatomical splenic position and the layout of its associated peritoneal reflections are demonstrated in ▶ Fig. 10.2.
The spleen is surrounded by peritoneum, with folds that meet
in positions anterior and posterior to the organ. The gastrosplenic ligament connects the spleen with the greater curvature
of the stomach anteriorly. The lienorenal ligament in turn connects the spleen to the retroperitoneum posteriorly. The tail of
the pancreas is partly located within this latter peritoneal
reflection and can be easily seen in close relation to the splenic
hilum on ultrasound. The splenic hilum effectively points medially between the stomach and the left kidney, both of which
leave an indentation. Medial to the gastrosplenic and lienorenal
ligaments is the lateral aspect of the lesser sac of the peritoneal
cavity. Further peritoneal reflections run from the spleen superiorly to the diaphragm (phrenicosplenic ligament) and inferiorly to the colon (splenocolic ligament).
Superiorly, the spleen is related to the diaphragm, lying in a
concavity within the left hemidiaphragm. Anteriorly, the organ
is related to the stomach and left colon. Posteriorly lie the diaphragm, left pleura, lung base, and chest wall.
Arterial blood supply comes through the splenic artery,
which is a branch of the celiac trunk of the aorta. This courses
behind the pancreas and reaches the spleen through the lienorenal ligament. The splenic artery divides into a number of
branches before entering the spleen. This is described to follow
two main patterns. In the distributed type (70%), the primary
trunk is short and many long branches reach the splenic hilum.
Right

Left

FL

Stomach
GH
Right

Left

GS

Liver

Liver

Spleen

LS
IVC AO

Stomach
RK

LR
LK

Spleen

Fig. 10.1 Developmental status of the spleen within the dorsal
mesogastrium at 5 weeks’ gestational age.

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Fig. 10.2 Anatomical drawing demonstrating the final position of the
spleen with the associated peritoneal reflections. AO, aorta; IVC, inferior
vena cava; FL, falciform ligament; GH, gastrohepatic ligament; GS,
gastrosplenic ligament; LR, lienorenal ligament; LS, lesser sac; LK, left
kidney; RK, right kidney


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Spleen

Fig. 10.3a,b Normal transverse ultrasound images of the spleen. a Position of the probe in the left lateral aspect. b Corresponding ultrasound image.
The stomach (St) can be seen anterior to the spleen.

Alternatively, in the magistral type (30%), the main trunk is long
with short arterial branches at the hilum. The splenic vein
forms in the lienorenal ligament from venous tributaries, which
leave the spleen at the hilum. The unified vein travels with the
artery behind the pancreas to join with the superior mesenteric
vein and form the portal vein.
Histologically, the spleen is formed by a fibrous capsule that
supplies a network of trabeculations serving as a supportive
framework for the functional tissue. The functional tissue consists of two types. The white pulp (which derives its name from
its appearance on gross pathology specimens) consists of
groups of lymphocytes and lymphoid follicles. The red pulp
comprises the remainder of the spleen (approximately 75% of
the volume) and is composed of venous sinusoids through
which the blood slowly filters.

10.1.3 Technique and Normal
Ultrasound Appearances
On interrogation with ultrasound, the normally located spleen
is identified in the left upper quadrant, above the left kidney
and under the left hemidiaphragm, either through a window
under the left lower rib margin or through the lower intercostal
spaces. Images should be obtained in the transverse and coronal
oblique planes along the length of the organ (▶ Fig. 10.3 and
▶ Fig. 10.4). These images can generally be obtained in the
supine position, although rotating the child into the lateral
decubitus position (▶ Fig. 10.5) can assist in obtaining a suitable
window when imaging in the supine position is proving difficult. Occasionally, the lung and pleura can partially obscure the
superior aspect of the spleen. The examiner can ask compliant
children, particularly older children, to hold their breath briefly
in expiration while he or she gently slides the probe up and

down the lower left intercostal spaces until the organ comes
into view (▶ Fig. 10.6; Video 10.6).

10.1.4 Echogenicity and Changes in
Echogenicity with Age
As a rule of thumb, the spleen is expected to have echogenicity
similar to that of the liver and appear more echogenic than the
adjacent kidney. This is assuming that the hepatic and renal
echogenicity is normal when these organs are used as a comparison for assessing the echogenic appearance of the spleen.
The spleen appears diffusely homogeneous. When it is evaluated with higher-frequency probes, the echotexture can
appear rather heterogeneous, and this finding should not be
misinterpreted as pathology (▶ Fig. 10.7). The degree of heterogeneity ranges from mild granularity to better-defined tiny
areas of hypoechogenicity throughout the organ. Some authors
have clearly demonstrated that these heterogeneous appearances change with age and are best identified in children between

the ages of 1 and 5 years. Such appearances are attributed to
the presence of white pulp/lymphoid follicles in the spleen,
which are thought to account for the tiny focal areas of low
echogenicity described.
The inability to demonstrate such heterogeneity in infants is
thought to result from the immaturity of the organ at this tender age. Difficulty in seeing such detail in older children may
result from their increased size, reducing the resolution
obtained, although the literature indicates that the chances of
demonstrating such heterogeneity increases both with age and
with organ size.
It is very important to become comfortable with normal
splenic appearances at different frequencies and with the various probes that are part of one’s regular equipment.

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Fig. 10.4a–c Normal coronal oblique ultrasound images of the spleen. a Position of the ultrasound probe. b Corresponding ultrasound image.
c The left kidney (LK) anterior to the spleen is visualized in the more coronal posterior plane.

Fig. 10.5 The lateral decubitus position can be helpful when images of
the spleen are obtained, particularly in the coronal/coronal oblique.

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Fig. 10.6 Coronal oblique ultrasound image demonstrating artifact
from the lung (white arrows), which obscures visualization of the spleen
(black arrow).

10.1.5 Vascularity
When interrogated with color Doppler ultrasound, the spleen
appears hyperemic. The splenic artery is seen to arise from the
celiac trunk and can be followed along its course behind the
pancreas into the lienorenal ligament and splenic hilum, where
its branches can be identified (▶ Fig. 10.8). Similarly, the draining venous tributaries are seen in the splenic hilum forming the
splenic vein. This can be followed behind the pancreas close to
the artery to its junction with the superior mesenteric vein
(▶ Fig. 10.9).

Fig. 10.7 Coronal oblique image of the spleen obtained with a highfrequency (12 MHz) planar probe in a 4-year-old child. The subtle,
diffuse, heterogeneous appearances throughout the organ should not
be misinterpreted as pathology.

identified incidentally on scanning. Their echogenicity is similar
to that of the main spleen. Splenunculi derive their blood supply from branches of the splenic artery.
Splenunculi are common and often of no clinical significance.
They rarely can present with torsion and infarction
(▶ Fig. 10.11). They can also significantly enlarge and become
hypertrophic, assuming the function of the larger spleen, in
hematopoietic conditions after a splenectomy, resulting in
recurrent hypersplenism.

Splenic Notch

10.1.6 Normal Variants
Splenunculi
In around 10% of healthy individuals, failure of all the embryonic splenic tissue to join and form a single spleen may result in
the presence of a small round or oval area of normal splenic tissue adjacent to the main splenic organ, known as an accessory
spleen or splenunculus. If multiple areas are present, these
are referred to as splenunculi (▶ Fig. 10.10). These are often

A small notch/cleft can occasionally be identified on the medial
aspect of the undersurface of the spleen (▶ Fig. 10.12). This is
thought to be a remnant from the fusion of the splenic nests of
tissue during embryonal development. This is easier to appreciate in cross-sectional imaging than with ultrasound. In the
context of trauma, the notch can be mistaken for a peripheral
laceration. However, one would expect some free fluid/hemoperitoneum adjacent to such a finding in the case of an acute
traumatic laceration.

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Fig. 10.8a–c Normal appearances of the splenic arterial blood supply. a Transverse midline ultrasound image of the retroperitoneum. b Same image
plane with color Doppler. In both images (a and b) the splenic artery can be seen originating from the celiac trunk and coursing behind the pancreas
toward the left (arrows). c Coronal oblique image at the splenic hilum with color Doppler showing the distal splenic artery (arrows) and its branches
within the spleen (arrowheads).

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Fig. 10.9a–c Normal appearances of the splenic venous drainage. a Transverse midline ultrasound image of the retroperitoneum. b Same image plane
with color Doppler. In both images (a and b) the distal splenic vein (white arrows) can be seen behind the body of the pancreas, forming the portal vein
(black arrow) after it joins with the superior mesenteric vein (out of plane) behind the neck of the pancreas. c Coronal oblique image at the splenic
hilum with color Doppler showing the venous tributaries in the hilum (arrows). These join to form one splenic vein.

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Fig. 10.10a,b Curvilinear (a) and planar high-frequency (b) coronal
oblique ultrasound images from a normal 10-year-old boy demonstrating an accessory spleen at the splenic hilum (arrows). Note that
the echogenicity and texture of the splenunculus and the larger spleen
are similar with both probes.

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Fig. 10.11a,b Fifteen-year-old boy presenting with acute abdominal
pain and fever. a Transverse ultrasound image demonstrates an oval
hypoechoic mass in the left upper quadrant (arrows). b Axial computed
tomography after contrast shows that the nonenhancing mass (white
arrows) lies anterior to the normal spleen (black arrow). This mass

represented an infarcted torted splenunculus.


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Spleen

Fig. 10.12 Axial computed tomographic scan demonstrating a splenic
cleft/notch (arrow), which should not be misinterpreted as pathology.

Fig. 10.13 Coronal oblique ultrasound image in a normal 10-year-old
child demonstrating the appropriate method for measuring the length
of the spleen.

Table 10.1 Splenic length in premature infants and neonates
Splenic length (cm)
Gestational age
(weeks)

No. of patients

Mean length
(± 1 SD)

Minimum–
maximum

24–31

29

2.4 (0.4)

1.6–3.2

32–35

34

2.8 (0.5)

1.7–4.0

36–37

35

3.3 (0.4)

2.6–4.2

38–41

155

3.4 (0.5)

2.4–4.9

Abbreviation: SD, standard deviation. Source: Reprinted with permission

of Elsevier from Soyupak SK, Narli N, Yapicioglu H, Satar M, Aksungur
EH. Sonographic measurements of the liver, spleen and kidney
dimensions in the healthy term and preterm newborns. Eur J Radiol
2002;43(1):73–78. Note: This study was performed in 261 healthy
newborn infants. Craniocaudal dimensions of the spleen were determined with ultrasonography.

10.1.7 Normal Splenic Size
The spleen grows with the growing child. Normal data are
available for splenic length in premature infants, neonates, and
older children (▶ Table 10.1 and ▶ Table 10.2). ▶ Fig. 10.13
demonstrates the appropriate method of measuring the spleen
in the coronal plane. At birth, the spleen measures between 2.5
and 4.9 cm in length. At full growth, the spleen is expected to
measure between 8.7 and 11.0 cm in a girl and 9.5 and 12.5 cm
in a boy.

Tips from the Pro
●

The spleen should be assessed systematically in two planes.
Always measure and document the craniocaudal length of
the spleen. Do get into the habit of assessing the splenic
echotexture with a higher-frequency probe. Although this
may not allow the full depth of the spleen to be assessed, it
provides great views of the echotexture and makes it possible to detect subtle lesions that, when small and diffuse, may
not be seen with standard probes and settings. Do not mistake the normal heterogeneity seen with higher-frequency
probes for pathology.

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Table 10.2 Splenic length in childhood
Spleen length (cm)

Spleen length (cm)

Age and sex

Number

Mean

SD

Min-max

Age and sex

Number

Mean

SD

Min-max

Age and sex

Number

Mean

SD

Min-max

Age and sex

Number

Mean

SD

Min-max

0–3 mo

6–8 y

F

22

4.4

0.57

3.2–5.5

F

25

8.2

0.99

6.6–10.0

M

35

4.6

0.84

2.8–6.8

M

26

8.9

0.91

7.4–10.5

F

6

5.2

0.47

4.5–5.6

F

26

8.7

0.92

6.4–10.5

M

10

5.8

0.65

4.9–7.0

M

15

9.0

1.02

7.4–11.2

F

15

6.3

0.68

5.1–7.5

F

34

9.1

1.09

6.8–11.4

M

12

6.4

0.78

5.4–7.4

M

19

9.8

1.05

7.3–11.3

3–6 mo

8–10 y

6–12 mo

10–12 y

1–2 y

12–14 y

F

18

6.3

0.69

5.1–8.2

F

30

9.8

1.02

7.9–11.6

M

17

6.8

0.72

5.6–8.3

M

18

10.2

0.81

8.5–11.7

F

24

7.5

0.83

5.7–8.9

F

13

10.3

0.69

8.7–11.0

M

22

7.6

1.07

5.9–9.9

M

13

10.7

0.90

9.5–12.5

F

36

8.0

0.74

6.7–9.5

M

18

8.1

1.01

6.4–9.9

2–4 y

14–17 y

4–6 y

F, female; M, male; SD, standard deviation.
Source: Robben S. Van Rijn R. Normal values. In: Differential diagnosis in Paediatric Radiology. Stuttgart: Thieme Medical Publishers. 2001:636–637.

10.2 Pathology
10.2.1 Abnormalities of Location and
Number
Wandering Spleen
The splenic peritoneal ligaments, which are pivotal in supporting the spleen, may be elongated, allowing the spleen to be displaced inferiorly from its expected location, even down to the
pelvis. An abnormally located spleen can be detected incidentally during a routine ultrasound examination or palpated clinically and may be suspected to represent an abdominal mass.

A wandering spleen may present with abdominal pain in either
of two different clinical scenarios: recurrent abdominal pain
from intermittent torsion or severe acute pain from torsion,
secondary ischemia and infarction of part or all of the spleen.
In the scenario of torsion, an ultrasound examination shows
the spleen to be absent from its normal location in the left
upper quadrant. Once identified, the spleen is found to be
enlarged, with a heterogeneous appearance. Focal infarctions
appear as areas of lower echogenicity with absence of flow on
interrogation with color Doppler. A whirlpool appearance of the
vascular blood supply at the hilum and secondary ascites can be
seen (▶ Fig. 10.14).

Splenic Fusion Abnormalities
Splenogonadal fusion is a rare developmental anomaly in which
aberrant splenic tissue is fused to ovarian or testicular tissue.

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Congenital fusion of splenic tissue with the kidneys (splenorenal fusion) has also been rarely described.

Splenosis
After traumatic rupture of the spleen or occasionally after surgical splenectomy, splenic cells can seed within the peritoneal
cavity and enlarge into functional masses of splenic tissue. The
splenic nodules/masses can be found anywhere in the peritoneal cavity. Extra-abdominal splenosis in the thoracic cavity is
also described. Such nodules may mimic other pathology (e.g.,
lymphoma) and can result in complications such as torsion or
recurrence of hemolytic disease after splenectomy.

Rotation Abnormalities and Heterotaxy

Syndrome
In complete situs inversus, the splenic tissue is located in the
right upper quadrant and the liver in the left upper quadrant.
All the vascular structures and solid organs are inverted in a
mirror image of the norm. In such cases, one may find multiple
splenules on the right instead of a spleen (▶ Fig. 10.15)
Heterotaxy syndrome is characterized by visceral malposition and indeterminate atrial arrangement. This spectrum
of conditions is generally rather simply classified as heterotaxy
syndrome with asplenia or heterotaxy syndrome with polysplenia, although patients with heterotaxy syndrome may not fit
into either category, and a number of anomalies may be present
in both groups.


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Fig. 10.14a–d Wandering spleen presenting with torsion and focal infarction in an infant. a Longitudinal panoramic view of the lower abdomen and
pelvis demonstrating the displaced enlarged spleen in the pelvis (white arrow), extending behind the bladder (black arrow). b, c Color Doppler axial and
longitudinal views of the vascular pedicle with whirlpool appearances (arrows). d Focal hypoechoic areas in the upper pole with absence of Doppler
signal are in keeping with areas of infarction (arrows).

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Fig. 10.15a–e Situs inversus with multiple splenules/polysplenia. a Plain chest X-ray demonstrating dextrocardia with a left-sided liver. b Transverse

ultrasound of the left upper quadrant demonstrating a left-sided liver that is a mirror image of normal. c Left-sided transverse ultrasound image
showing the gallbladder (black arrow) located in the left upper quadrant. d, e Longitudinal images of the right upper quadrant demonstrating multiple
right-sided splenunculi (arrows). As the spleen develops in the dorsal mesogastrium, these would be located on the same side of the stomach.

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In heterotaxy syndrome with asplenia, as the name suggests,
there is absence of the spleen or splenic tissue. This is also
referred to as right-sided isomerism. In the chest, the bronchial
tree follows the right-sided pattern bilaterally, and there are
bilateral systemic atria. Complex cardiac malformations are
common. The spectrum of abnormalities in the abdomen
includes absence of the spleen, a midline location of the liver,
an indeterminate position of the stomach, and a location of the
aorta and inferior vena cava on the same side of the spine.
Clinically, apart from all the issues related to the above anomalies, the absence of splenic tissue predisposes such children to
sepsis.
In heterotaxy syndrome with polysplenia, multiple small
spleens/splenunculi are seen, with no large single splenic organ
(▶ Fig. 10.16 and ▶ Fig. 10.17). This is also referred to as bilateral left-sidedness or left isomerism because the bronchial tree
follows the left-sided pattern and there are usually bilateral
pulmonary atria. The spectrum of abnormalities in the abdomen include a central liver, indeterminate position of the stomach, extrahepatic biliary atresia, interruption of the inferior
vena cava with continuation of the azygos system, and the presence of common celiac and mesenteric arteries. In 90% of cases,
cardiovascular anomalies are present. There are described cases
in which other features of left isomerism are present without
an increased number of spleens. The accessory splenic tissue

does not necessarily have to lie in the left upper quadrant but
may even be seen in the right upper quadrant dependant on
the location of the stomach. These splenic anomalies in heterotaxy syndromes can be explained from an embryological
aspect. It has been demonstrated that splenic tissue precursors
exist at both sides of the midline but, in normal cases, there is
preferential unilateral development of the left sided tissue.
Therefore, in bilateral left sidedness one would expect the end
result to be increased/accessory splenic tissue. In bilateral right
sidedness the end result would be the absence of splenic tissue.
The incidence of malrotation and nonrotation (▶ Fig. 10.17)
is increased throughout the spectrum of heterotaxy syndromes.

Abnormal Location of a Normal Spleen
Secondary to Disease
Occasionally, the spleen can be displaced from its normal
location by other pathologic processes, such as left-sided retroperitoneal masses. ▶ Fig. 10.18 demonstrates a normal
spleen displaced by neuroblastoma in a 2-year-old child. The
normal spleen never returned to its normal location, even
after treatment.

10.2.2 Abnormalities of Size
Enlargement of the spleen is a nonspecific finding. A small
number of children can have a normal palpable spleen under
the rib margin. Abnormalities in the splenic size may be secondary to generalized enlargement of the spleen or to focal
abnormalities within the spleen, both of which may be clinically detected as splenomegaly.

Generalized Splenomegaly
In generalized splenomegaly, the spleen increases in size in all
planes, but elongation is evident mostly in the craniocaudal
dimension. Measurements should be obtained as demonstrated

in ▶ Fig. 10.13. Indications of enlargement include a rounded,
bulky lower splenic pole and extension of the spleen beyond
the lower pole of the left kidney. Given the constant gradual
increase in size with growth in children, unlike in the adult
population, it is less useful to classify causes of enlargement
according to the degree of splenomegaly. Pathologically, the
most common causes of splenomegaly are infection
(▶ Fig. 10.19), malignancy, hemolytic anemia (▶ Fig. 10.20),
storage disorders, and portal hypertension (▶ Fig. 10.21).
▶ Table 10.3 outlines the most common causes of splenomegaly
in children.

Focal/Localized Abnormalities
Splenic Cysts
Simple cysts in the spleen are often identified incidentally,
although when large, these can present with splenomegaly or
mass effect. Cysts in the spleen can be congenital or acquired
(see box Possible causes of cysts in the spleen). Congenital
cysts are also referred to as epithelial or epidermoid cysts. On
ultrasound, these typically appear as well-defined, round or
oval, anechoic thin-walled areas with posterior acoustic shadowing surrounded by normal splenic tissue. Internal echoes can
also be demonstrated. On interrogation with Doppler ultrasound, there is an absence of blood supply within these lesions.
Congenital cysts can be detected antenatally, and it can be quite
challenging to be specific about the anatomical location of the
cyst. (▶ Fig. 10.22 and ▶ Fig. 10.23).

Table 10.3 Causes of pediatric generalized splenomegaly
Cause

Examples

Infection

Viral infection (e.g., Epstein–Barr virus)
Bacterial infection (e.g., tuberculosis, brucellosis;
▶ Fig. 10.19)
Fungal infection (e.g., candidiasis)
Protozoal infection

Hematopoietic
conditions

Abnormal red blood cells (e.g., spherocytosis;
▶ Fig. 10.20)
Hematopoietic activity of the spleen

Malignancy

Lymphoma, either generalized enlargement or
focal lesions; typically hypoechoic lesions with no
Doppler within (▶ Fig. 10.32)

Storage disorders

Gaucher syndrome; Niemann–Pick disease

Portal hypertension

Most frequent in cases of previous portal vein
thrombosis (▶ Fig. 10.21)

Congestive cardiac
failure

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Fig. 10.16a–c Heterotaxy syndrome with polysplenia in a 15-year-old. a Reformatted coronal computed tomographic (CT) scan demonstrating a
normal left-sided cardiac apex (white arrow), a left-sided liver, and a right-sided stomach (black arrow). b Reformatted coronal CT scan demonstrating
multiple small splenules (splenunculi) in the right upper quadrant (arrows). c Equivalent right-sided longitudinal ultrasound image demonstrating the
same splenules in the right upper quadrant (arrows).

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Fig. 10.17a–d Heterotaxy syndrome with polysplenia in a neonate. a Chest X-ray demonstrates dextrocardia. A bilateral left-sided bronchial pattern
can be seen. b Midline transverse ultrasound image demonstrating a central liver. c Oblique coronal ultrasound image demonstrating numerous
adjacent splenules in the left upper quadrant (arrows). d Image from barium follow-through examination demonstrating a left-sided stomach and
nonrotation of the bowel, with the small bowel located in the right side of the abdomen.

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Acquired cysts (pseudocysts) may be the end result of a traumatic contusion, infection, or infarction (▶ Fig. 10.24). Patients
with traumatic cysts would be expected to have a relevant
history, and previous imaging at the time of trauma may be
available, although not always. The ultrasound appearance of
these can be completely identical to that of true congenital
splenic cysts. Cysts that are clearly thick-walled and/or contain
irregular contents are more likely to be infective. One further
consideration would be a simple cyst that has subsequently
bled.

Pyogenic Splenic Abscesses
A pyogenic splenic abscess can result from focal infection in the
spleen with secondary necrotic breakdown into an infected
cyst. Secondary septic abscesses in the spleen are described in a
myriad of distant infections (e.g., subacute bacterial endocarditis, urinary tract infections, respiratory tract infections). Secondary infection may also develop in a previously sterile cyst,
in a splenic infarct, or in a traumatic hematoma. The history
and previous imaging can help in this scenario. Patients with
hemoglobinopathies are at increased risk for splenic abscesses.
Findings suggesting infection are an ill-defined complex cyst
with heterogeneous echogenic contents and possibly septa in
the context of a child with sepsis.
Fig. 10.18a,b Abnormal location of a normal spleen after resection of a
large intra-abdominal neuroblastoma. a Axial T2 magnetic resonance
(MR) image showing the location of the spleen (white arrows) to be
medial to the normal, expected position. Note residual disease in the
left paraspinal region (black arrow). b MR imaging ADC (apparent

diffusion coefficient) map showing normal, expected restricted
diffusion of the spleen (arrows).

Possible causes of cysts in the spleen
●

●

●

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Congenital cysts
○ True (epidermoid) cyst (▶ Fig. 10.23)
Acquired
○ Secondary to infection: pyogenic abscess, echinococcosis,
fungal microabscesses (small and multiple; ▶ Fig. 10.25)
○ Secondary to traumatic contusion (▶ Fig. 10.24)
○ Secondary to previous splenic infarction
○ Cystic benign tumor (e.g., hemangioma)
○ Lymphangioma (may appear as predominantly cystic,
characteristically with septa; ▶ Fig. 10.28)
○ Pancreatic pseudocyst
Cystic metastasis (rare)

Multiple Abscesses
Fungal microabscesses typically show up as multiple tiny, hypoechoic cystic areas in the spleen (▶ Fig. 10.25). In the correct
clinical context, such as a child with febrile neutropenia, such
appearances are very characteristic and should be actively
sought. This may not be appreciated unless the organ is carefully assessed with a higher-frequency probe.

Solid Focal Heterogeneities in the Spleen (Solid
Splenic Abnormalities)
The majority of solid masses in the spleen in children is benign.
▶ Table 10.4 outlines the differential diagnosis for hypoechoic
and hyperechoic solid lesions in the spleen. The following section describes in detail some of the most common causes.

Hemangiomas
Hemangiomas are nonencapsulated vascular channels of variable size that are thought to arise congenitally. They are most


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Fig. 10.19a–d Confirmed brucellosis in a 10-year-old. a, b Coronal oblique ultrasound images of the left upper quadrant demonstrating a significantly
enlarged spleen (measuring up to 17 cm). Note that the distal pole of the spleen extends beyond the lower pole of the left kidney (arrows).
c Longitudinal ultrasound image of the gallbladder demonstrating associated marked edema of the gallbladder wall (arrows). d Transverse image at
the liver hilum demonstrating associated periportal lymphadenopathy (arrows).

Fig. 10.20a,b Splenomegaly in a 16-year-old with hereditary spherocytosis. a Coronal oblique ultrasound image of the left upper quadrant
demonstrating a significantly enlarged spleen extending inferiorly beyond the rib cage. b Transverse midline abdominal image at the level of the distal
splenic vein demonstrating associated enlargement of the splenic vein (arrows).

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Fig. 10.21a–c Splenomegaly in a 14-year-old with portal hypertension. a Coronal oblique ultrasound image of the left upper quadrant demonstrating
a significantly enlarged spleen (measuring up to 18 cm). b Coronal oblique ultrasound image at the liver hilum showing enlargement of the portal vein
(arrows). c Doppler ultrasound evaluation of the falciform ligament demonstrates venous flow, in keeping with venous recanalization (arrow).

Table 10.4 Solid lesions of the spleen
Hypoechogenic solid lesions
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●
●
●

●
●
●
●

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Hemangioma (hypervascular on Doppler; ▶ Fig. 10.27)
Hamartoma (▶ Fig. 10.30)
Inflammatory pseudotumor (hypervascular)
Vascular tumors (with heterogeneous appearances), such as
hemangioendothelioma (▶ Fig. 10.31), lymphoma (▶ Fig. 10.32;
Video 10.32), leiomyoma (▶ Fig. 10.33), Langerhans cell
histiocytosis (▶ Fig. 10.36)
Peliosis
Storage disorders (e.g., Gaucher disease)
Infarction (may mimic mass in early stage)
Infection (before breakdown into abscess may mimic a mass)

Hyperechogenic solid lesions
●

●
●
●

●
●

Calcifications (see box Causes of focal calcifications in the spleen
(may be single or multiple))
Hemangioma (▶ Fig. 10.26)
Lymphangioma (▶ Fig. 10.28)
Vascular tumors (with heterogeneous appearances), such as
hemangioendothelioma (▶ Fig. 10.31)
Storage disorders (rarely increased echogenicity)
Acute hematoma (may mimic hyperechoic mass lesion; ▶ Fig. 10.38)


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Lymphangiomas
Pathologically, lymphangiomas consist of abnormal dilated vascular channels of the lymphatic system. They can occur in isolation, involving only the spleen (▶ Fig. 10.28), or can be multiple
or part of a more generalized process referred to as lymphangiomatosis (▶ Fig. 10.29). Focal lymphangiomas can have
varying appearances on ultrasound, depending on the size of
the cystic spaces containing lymph. Typically, such lesions demonstrate septate hypoechoic cystic areas, as in other regions of

the body, or less commonly are seen as solid, hyperechoic
abnormalities (microcystic, in which case the cysts are not well
appreciated). Calcifications may occasionally be seen in the
septa/walls of the lesion.

Splenoma/Hamartoma
This is the most common benign tumor mass in the spleen,
thought pathologically to consist of unorganized vascular channels with intervening disorganized stroma with or without
lymphoid follicles. The ultrasound appearances are nonspecific,
and such masses can appear hyper- or hypoechoic on ultrasound. Hamartomas can have cystic elements and calcifications.
There is retained blood supply on interrogation of the solid
components with Doppler ultrasound (▶ Fig. 10.30).

Other Vascular Tumors of the Spleen
Because it is such a vascular organ, the spleen is affected by a
number of tumors of vascular origin. Littoral cell angiomas
and hamartomas (see above) occur in the spleen. Other hypervascular tumors described include hemangioendothelioma
(▶ Fig. 10.31), sclerosing angiomatoid nodular transformation,
and angiosarcoma (malignant outcome).

Splenic Focal Abnormalities Associated with Storage
Disorders
Fig. 10.22a,b a Longitudinal ultrasound of a neonate with a cyst at the
splenic hilum (arrows). This was detected on antenatal scans. Note the
absence of Doppler signal within the cyst. b Axial T2 magnetic
resonance image demonstrates the location of the cyst in the medial
aspect of the splenic hilum (arrows). It can be difficult to identify the
organ of origin of such a cyst if the cyst is not surrounded by a rim of
normal tissue from the organ of origin.

often small and identified incidentally, but they may be large
and complicated by excess red blood cell breakdown. The ultrasound appearances are nonspecific, and these masses most
commonly appear hyperechoic in comparison with the rest of
the spleen (▶ Fig. 10.26). They may also appear hypoechoic
(▶ Fig. 10.27) or isoechoic, or rarely as cystic lesions. Hemangiomas typically demonstrate increased Doppler flow
(▶ Fig. 10.26 and ▶ Fig. 10.27). Echogenic calcifications within
the lesions are also described. Hemangiomas usually occur in
isolation but may be multiple, more commonly in the context
of underlying conditions that predispose to such lesions, such
as Klippel-Trenaunay syndrome.

Rare storage disorders such as Gaucher disease and Newman–
Pick disease can involve the spleen. Focal splenic ultrasound
lesions are identified. These appear as hypoechoic, hyperechoic,
or mixed hypo- and hyperechoic abnormalities and can alter in
appearance with treatment.

Lymphoma
The spleen can be involved in lymphoma. Appearances are variable and nonspecific, either with a generalized increase in the
size of the organ or with focal single or multiple masses appreciated on ultrasound. Focal masses generally appear hypoechoic
and can be hypovascular when interrogated with Doppler ultrasound (▶ Fig. 10.32).

Tips from the Pro
●

When a solid lesion is identified in the spleen, evaluate the
Doppler characteristics of the mass. This may help shorten
the differential diagnosis. Absence of Doppler signal does not
mean that the mass is not solid. Pathologies manifesting as
solid focal splenic deposits with decreased Doppler signal

compared with the adjacent normal splenic tissue include
lymphoma and sometimes lymphangioma.

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Fig. 10.23a–d Sixteen-year-old with learning disabilities and long-term issues with swallowing. a Abdominal radiograph from a barium follow-through
series shows evident splenomegaly (arrows) and displacement of the duodenum and small bowel to the right. b, c Transverse ultrasound images
demonstrating a large complex cystic lesion in the spleen (arrows) with posterior acoustic enhancement. d Coronal oblique image of the same
complex cyst (arrows). The spleen was subsequently removed, and the cyst proved to be a congenital epidermoid cyst.

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Spleen

Fig. 10.24 Coronal oblique ultrasound image showing a complex
posttraumatic splenic cyst with echogenic cellular contents (arrows) in
a 14-year-old patient.

Fig. 10.25a,b Fungal microabscesses in the spleen. Three-year-old immunosuppressed child with persistent fever. (a) Coronal oblique image of the
spleen obtained with a curvilinear probe. (b, c) Images obtained with a higher-frequency planar probe. (continued)

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Fig. 10.25c–e (continued) (d) Higher-frequency image with color Doppler interrogation. Multiple focal hypoechoic areas are diffusely spread
throughout the spleen. These were subsequently shown to represent Candida microabscesses. (e) Eight-year-old girl with confirmed Candida
infection. Higher-frequency image of the lower pole of the spleen demonstrates a focal, well-defined hypoechoic area containing central
echogenicities that probably represent early calcifications.

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Fig. 10.26a–c Four-year-old girl with a typical splenic hemangioma. a Coronal oblique curvilinear probe ultrasound image. b Coronal oblique higherfrequency ultrasound image. These images demonstrate a focal round area of increased echogenicity within the splenic lower pole (arrows).
c Transverse higher-frequency ultrasound image with Doppler interrogation demonstrates increased Doppler blood flow within the hemangioma
(arrows).

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Fig. 10.27a–c Twelve-year-old girl with an incidental splenic hemangioma. a Coronal oblique curvilinear probe ultrasound image. b Coronal oblique

higher-frequency ultrasound image. These images demonstrate a focal round area of slightly decreased echogenicity within the center of the spleen
(arrows). c Transverse higher-frequency ultrasound image with Doppler interrogation demonstrates increased Doppler blood flow within the
hemangioma (arrows).

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Fig. 10.28a–d Eleven-year-old girl with a typical splenic lymphangioma. a Coronal oblique curvilinear probe ultrasound image demonstrates the
overall appearance of the spleen, with multiple adjacent thin-walled cystic areas (arrows). b, c Higher-frequency planar images better show the cystic
characteristics of the mass, with posterior acoustic enhancement (arrows) deep to the cysts. d Higher-frequency planar image obtained slightly more
laterally in the same patient demonstrates smaller cysts within the same mass.

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