Neuroblastoma pediatric

Neuroblastoma pediatric



• Neuroblastoma (NBL) along with
ganglioneuroblastoma and ganglioneuroma
constitute a group of tumours of ganglion cell origin
that derive from primordial neural crest cells, which
are the precursors of the sympathetic nervous system
• The degree of malignancy is designated by the degree
of cellular and extra-cellular maturation of these
tumours. The most undifferentiated and aggressive
NBL presents in young children (median age  2
years). 


• The median age at diagnosis is 22 months.
More than 90% of the diagnosed cases are
children aged  5 years, with peak incidence at
age of 2–3 years
• Boys are more frequently affected than girls.


Sites of origin
• NBLs arise from the adrenal glands or follow
the distribution of the sympathetic ganglia
along paraspinal areas from the neck to the
pelvis
• The most common primary site for NBL

development is the retroperitoneum, the
adrenal medulla (35%) and the extra-adrenal
paraspinal ganglia (30%–35%)


Biologic prognostic factors
• the Myc-N gene, a proto-oncogene located on
the distal end of the chromosome arm 2p, was
found to be amplified, present in multiple
(>10) copies, in 20%–30% of NBLs. Myc-N
amplification is associated with rapidly
progressive disease and a poor outcome


Clinical presentation
• NBLs can be discovered incidentally
• Pediatric abdominal tumors are often very
large at initial presentation, because most
children come to attention because someone
noted severe abdominal distention. 
• It may seem a contradiction, but in very large
tumors, it is usually more difficult to ascertain
the organ of origin. 


Clinical presentation
• The usual finding in a child with NBL is an abdominal
mass; additional findings are renin-associated
hypertension (from renal artery compression)
• Unwell from metastatic spread of the tumour:

Generalised skeletal pain or even arthritis-type
complaints, effects of hormone production and nonspecific findings from bone marrow involvement,
such as weight loss, malaise, anaemia, fever and
irritability, can be encountered


Plain radiograph
• Appearances are nonspecific, typically
demonstrating an intraabdominal soft-tissue mass
displacing adjacent organs.
Pressure on adjacent bones
may cause remodeling of
ribs, vertebral bodies or
pedicle thinning. Up to 30%
may have evidence of
calcification on the plain
film.


Ultrasound
• On Ultrasound the tumor is generally
echogenic and inhomogeneous with bright
calcifications.
A feature of neuroblastoma is the tendency of
vascular encasement and they have a
tendency to grow between the vertebral
column and the aorta which is lifted ventrally.


Ultrasound

• 3.5-year-old girl with malaise.
(a) Abdominal US, sagittal
plane, shows a heterogeneous
lesion with multiple internal
echogenic foci in the right
retroperitoneum that displaces
the diaphragm superiorly. (b)
Abdominal US, axial plane at
the level of the renal arteries,
shows anterior displacement of
the aorta, IVC and renal arteries
with preserved patency. 



CT
• On CT, NBLs present as large, heterogeneous, lobulated softtissue masses that show heterogeneous or little enhancement
• Coarse, finely stippled or curvilinear calcifications are seen in
85% of the abdominal NBLs on CT. Low attenuation areas seen
within the tumour represent pseudo-necrosis or haemorrhage
• Adjacent organs are usually displaced, although in more
aggressive tumors direct invasion of the psoas muscle or 
kidney can be seen. The latter can make distinguishing
neuroblastoma from Wilms tumor difficult.
• Lymph node enlargement is often present.



CT
• pre-operative surgical planning

• contrast-enhanced images can delineate the
vasculature to best effect
• post-chemotherapy, the solid portions of the
mass are easier to define than on MRI and the
extent of calcification, which increases after
treatment and which can be important for the
surgeon to appreciate before surgery, is more
easily characterised


Large heterogenously enhancing mass
compressing the left kidney.
Cavernous transformation of the portal vein
likely secondary to obstruction by mass.
Ascites.


Imaging of a 2.5-year-old girl with malaise
and abdominal distension. (a) Coronal CT
reconstruction after injection of contrast
medium shows a large heterogeneous low
attenuating lesion with calcification in the
right suprarenal area. It extends across the
midline, and surrounds the IVC. Secondary
involvement of the liver is also noted. (b)
Coronal CT reconstruction in the same
patient post chemotherapy, shows significant
reduction in the size of the primary lesion but
the portal vein remains encased (inoperable
NBL).

MRI
• MRI should now be the cornerstone imaging modality
for all primary NBL tumours whether in the neck, chest,
abdomen or pelvis
• MRI can easily assess the extent of disease, being
superior to CT in assessing metastatic marrow disease,
chest wall invasion and spinal canal involvement
• Epidural extension of NBL and leptomeningeal
dissemination are better assessed with MRI which
should be performed on any child with paraspinal NBL


• On MRI, the tumour is typically heterogeneous with a variable
enhancement pattern
• T1: heterogeneous and iso to hypointense
• T2
– heterogeneous and hyperintense
– cystic/necrotic areas very high intensity

• C+ (Gd): variable and heterogeneous enhancement
• Cystic and haemorrhagic areas within the tumour can be
convincingly identified but not calcification
• On diffusion-weighted images, NBLs show increased tumour
signal which is attributed to restricted diffusion
• Bone marrow disease is usually seen as diffuse infiltration but it
may also present a nodular pattern with areas of low and high
signal intensity on T1W and T2W images, respectively.

Coronal T2 MR of a 3 year old boy with
extensive abdominal NBL that crosses the
midline and is here seen to encase the aorta
(blue arrow).

Axial T2 MR of 2 year old girl showing
NBL with rib invasion (blue arrow),
anterior aortic displacement and
encasement (red arrow) and bilateral
pleural effusions.


Axial T2 MR of 3 year old boy showing
intraspinal extent of NBL with tumour seen in
both neural foramina on this single image
(blue arrows).

Coronal T2 MR of a 2 year old boy
showing left-sided NBL mass with bone
marrow involvement (blue arrow).


Neuroblastoma vs Wilms tumor
Neuroblastoma

Wilms tumor

• calcification very common: 90%

• encases vascular structures but does not
invade them
• younger age group (<2 years of age)
• poorly marginated
• elevates the aorta away from the vertebral
column
• more commonly crosses the midline, especially
behind the aorta  
• more common to have extension into the chest
• bone metastases are common (
Hutchinson syndrome)
• extension into spinal canal can be seen
• retroperitoneal lymph nodes are more often
seen

• calcification uncommon: 10-15% (10% rule of
Wilms tumor)
• displaces adjacent structures without
insinuating between them, also with
displacement of the renal vessels
• slightly older age group: peak 3-4 years of age
• well-circumscribed
• claw sign with the kidney
• extension into IVC/renal vein
• bone metastases are rare, rather lung
metastases are common
• extension into spinal canal never seen
• retroperitoneal lymphadenopathy is
uncommon
• higher incidence of hemorrhage