The document discusses various pediatric retroperitoneal masses. It begins by noting that abdominal masses are most common in children under 5 years old and retroperitoneal masses in neonates are often kidney-related and benign. It then characterizes the retroperitoneal space and lists common retroperitoneal organs. Several pathologies are discussed in detail, including neuroblastoma, Wilms tumor, nephroblastomatosis, and renal cell carcinoma. Imaging findings for many conditions are provided. The document serves as an overview of pediatric retroperitoneal masses and their imaging appearances.

1. Pediatric
Retroperitoneal
Masses
Dr Suhas B
Resident (MD Radio-diagnosis)

2. Introduction
• Abdominal masses are most common in children under the age of 5 years
• Most abdominal masses in neonates are retroperitoneal, of kidney origin and are not
malignant
• The older the child the more likely the mass represents a malignant process
• Of the primary retroperitoneal neoplasms, 70%–80% are malignant in nature, and
these account for 0.1%–0.2% of all malignancies in the body.
• A clear knowledge of these retroperitoneal masses is important for appropriate
diagnosis.

3. Retroperitoneum
• The retroperitoneum is the part of the abdominal cavity that lies between the
posterior parietal peritoneum and anterior to the transversalis fascia.
• It is divided into three spaces by the peri renal fascia (Fascia's of Gerota and
Zukerlandl) and is best visualized using CT or MRI .The Three spaces are:
 anterior pararenal space
 perirenal space
 posterior pararenal space

5. Retroperitoneal organs
• Duodenum and pancreas
• Ascending and descending colon
• Kidneys and ureters
• Bladder and uterus
• Great vessels
• Rectum

6. Interfascial Planes
• Retromesenteric
• Retrorenal
• Lateroconal interfascial plane,
• Combined interfascial planes

15. Characterization of
the Retroperitoneal Space
• Anterior displacement of retroperitoneal organs (eg, kidneys, adrenal glands, ureters, ascending and
descending colon, pancreas, portions of the duodenum) strongly suggests that the tumor arises in the
retroperitoneum.
• Major vessels and some of their branches are also found in the retroperitoneal cavity, so that
displacement of these vessels can be helpful as well.

16. Solid Neoplastic Masses
Solid neoplasms in the retroperitoneum can be broadly divided into four groups:
(a) mesodermal neoplasms;
(b) neurogenic tumors;
(c) germ cell, sex cord, and stromal tumors; and
(d) lymphoid and hematologic neoplasms.

17. Lipoblastoma
• rare, benign, encapsulated tumour arising from embryonic white fat.
• Type of mesenchymal tumor
• occurs primarily in infancy and early childhood
• asymptomatic, painless, progressively growing masses in the superficial or subcutaneous soft tissue
• occurs in the extremities and trunk
Imaging
• well defined, often with a lobular appearance and internal septations, at sonography, CT, and MR imaging
• echogenic regions, areas of low attenuation, or areas of signal intensity identical to that of subcutaneous
adipose tissue with all pulse sequences
• myxoid areas are hypoechoic at sonography, low attenuation at CT, and at MR imaging are low signal
intensity with T1WI and high signal intensity with T2WI (water)
• enhance with contrast material, owing to the rich capillary network

18. Retroperitoneal Lipoblastoma in a 8 year old male

19. Neuroblastoma
• neuroblastic origin correspond to the most common extracranial solid childhood malignancies, and the third
commonest childhood tumours after leukaemia and brain malignancies.
• ~15% of childhood cancer deaths
• 95% of cases diagnosed before the age of 10 years.
• arise from the primitive neuroectodermal cells or neural crest cells.
• pain or a palpable mass and abdominal distension, HTN, sweats, diarrhea, irritability
• adrenal glands (35%), Retroperitoneum (30-35%), posterior mediastinum (20%), neck: 1-5%, Pelvis: 2-3%
• congenital neuroblastoma is defined as neuroblastoma identified within a month of birth and could be infantile or
neonatal type.
• Infantile type – seen mostly in adrenals; diagnosed within 19 weeks of gestation; excellent prognosis
• Neonatal type – 60% present with metastases at the time of the diagnosis; 90% cure rate
• Associations – Blueberry muffin syndrome, Hutchinson syndrome, Opsomyoclonus, Pepper syndrome, DiGeorge
syndrome, Beckwith Wiedemann syndrome, NF 1, Hirschsprung disease

20. Raccoon eyes and Clown face

21. Imaging
 Ultrasound - Neuroblastoma on ultrasound demonstrates a vascularity; areas of necrosis that appear as
regions of low echogenicity. Calcification +/-
 CT -
• heterogeneous with calcifications seen in 80-90% of cases. Areas of necrosis are of low attenuation.
• insinuating itself beneath the aorta and lifting it off the vertebral column.
• tends to encase vessels and may lead to compression.
• aggressive tumours - invasion of the psoas muscle or kidney can be seen.
 MRI -
• T1 - heterogeneous and iso to hypointense
• T2 - heterogeneous and hyperintense; cystic/necrotic areas very high intensity, signal voids may be evident
• C+ (Gd): variable and heterogeneous enhancement

22. 7 year old male
11 year old male
15 year old female

23. T1WI T2WI
T1+C
11 year old
male with left
adrenal
neuroblastoma

24. Mets – bone (MC), lung and pleura, brain and meninges

25. Ganglioneuroma
• fully differentiated neuronal tumours that do not contain immature elements.
• usually asymptomatic; discovered incidentally as they are slow growing and usually endocrinologically
inactive.
• derived from the primordial neural crest cells
• posterior mediastinum (41.5%) or retroperitoneum (37.5%). Other- adrenal gland (21%) and neck (8%)
• Associations - multiple endocrine neoplasia type 2b
Imaging
Lesions are generally well defined and can be quite large at presentation.
CT - Typically seen as well-circumscribed, solid, encapsulated masses that are iso to hypoattenuating to
muscle. The lesion may also demonstrate calcifications (~20% ) which is typically fine and speckled, but may
be coarse.

26. MRI
• T1: tends to have homogeneously low or intermediate signal
• T2: tends to have heterogeneously intermediate or high signal
• T1 C+ (Gd): variable ranging from none to heterogeneous enhancement
• ADC: ADC values tend to be higher to that of a neuroblastoma

27. 12 year old female
presenting with
retroperitoneal mass
8 year old male with
right adrenal
ganglioneuroma

28. 16 year old with
left retroperitoneal
ganglioneuroma
T1WI T2WI
T1+C

29. Ganglioneuroblastoma
• an intermediate-grade tumor that has elements of benign ganglioneuroma and malignant neuroblastoma.
• a pediatric tumor occurring in the 2–4-year age group.
• Arise from sympathetic cells
• Painful abdominal mass; HTN, irritability, diarrhea due to catecholamine
• tumor could be solid or cystic with solid components.
Associations - von Recklinghausen disease, Beckwith-Wiedemann syndrome, Hirschsprung disease, central
failure of ventilation, and DiGeorge syndrome
USG - heterogeneously echogenic; anechoic areas within the tumor corresponding to hemorrhage or necrosis
CT - large and heterogeneous, demonstrate calcification; Vascular encasement and compression may occur,
Regional invasion of musculature may occur, and invasion of the neural foramen into the epidural space.
Metastases can occur into the lung, pleura, brain and meninges

30. MRI - typically heterogeneous, variably enhancing, and of relatively low signal
intensity on T1-weighted images and high signal intensity on T2-weighted
images. Calcification - signal voids may be apparent. Hemorrhagic areas- high
signal intensity on T1-weighted images, and cystic change- bright on T2-
weighted images

32. Pheochromocytoma
• uncommon tumour of the adrenal gland
• 10% are found in children
• frequently in children aged 6-14 years (average, 11 y)
• Present with headache, diarrhea, vomiting, tremors, HTN
• occurs wherever chromaffin tissue is found (adrenal medulla MC)
• Associations - neurofibromatosis, von Hippel-Lindau disease, tuberous sclerosis, Sturge-Weber syndrome,
and as a component of multiple endocrine neoplasia (MEN)

33. CT
• overall sensitivity of 89%.
• usually large, heterogeneous masses with areas of necrosis and cystic change; they typically enhance
avidly
• may wash out similar to an adrenal adenoma, but they tend to have a greater enhancement in an arterial
or portal venous contrast phase (PV>Art)
• 110 HU of enhancement on the arterial phase is compatible with pheochromocytoma; up to 7%
demonstrate areas of calcification
MRI
• T1 - slightly hypointense to the remainder of the adrenal, heterogeneous if hemorrhagic
• T2 - markedly hyperintense (lightbulb sign): this is a helpful feature; areas of
necrosis/haemorrhage/calcification will alter the signal
• in-phase/out-of-phase: no signal loss on out-of-phase imaging (pheochromocytomas do not contain large
amount of intracellular lipid)
• T1 C+ (Gd) - heterogeneous enhancement; enhancement is prolonged, persisting for as long as 50 minutes

35. 8 year old female with right adrenal pheochromocytoma

36. Adrenal Hemorrhage
• When unilateral, it is often clinically silent. In contrast, bilateral adrenal haemorrhage can lead to
catastrophic adrenal insufficiency
• frequently attributed to adrenal vein spasm or thrombosis
• commonest presentation is abdominal mass; jaundice is also common
Ultrasound
• an early-stage haematoma - solid with diffuse or inhomogeneous echogenicity
• as liquefaction occurs - mixed echogenicity with a central hypoechoic region and eventually becomes
completely anechoic and cyst-like
• calcification may be seen; mass is avascular.

38. CT
• haematomas characteristically appear round or oval, often with surrounding stranding of the periadrenal
fat.
• acute to subacute haematomas - high attenuation that usually range from 50-90 HU
• haematomas decrease in size and attenuation over time, and most resolve completely
• organised chronic adrenal haematoma - mass with a hypoattenuating centre, with or without calcifications
(also known as adrenal pseudocysts)
• adrenal haematomas may calcify after one year
MRI
• acute stage (<7 days after onset): isointense or slightly hypointense on T1 weighted images and markedly
hypointense on T2 weighted images
• subacute stage (7 days to 7 weeks after onset): hyperintense on T1 and T2 weighted images
• chronic stage (typically >7 weeks after onset): a hypointense rim is present on T1 and T2 weighted images-
haemosiderin deposition and the presence of a fibrous capsule.

39. large right adrenal hemorrhage

40. Rhabdomyosarcoma
• malignant tumour with skeletal muscle cell morphology
• most common soft tissue tumour in children and account for 5-8% of childhood cancers
• 65% of all rhabdomyosarcomas are diagnosed in patients under 10 years old with slight male predilection
(M:F 1.67:1)
• rapidly growing masses; localised pressure effects on neurovascular structures, and have a predilection for
growing into bones
• genito-urinary: ~25%, paratesticular: ~20%, bladder: ~5%
• Associations - neurofibromatosis type I (NF1), Beckwith-Wiedemann syndrome, Li-Fraumeni syndrome,
Costello syndrome

41. Imaging
Ultrasound - heterogeneous well-defined irregular mass of low to medium echogenicity
CT
soft tissue density
some enhancement with contrast
adjacent bony destruction seen in over 20% of cases
MRI
T1
low to intermediate intensity, isointense to adjacent muscle
areas of haemorrhage are common in alveolar and pleomorphic subtypes
T2
hyperintense
prominent flow voids may be seen particularly in extremity lesions 7
T1 C+ (Gd): shows considerable enhancement

43. Lymphangioma
• benign lesions of vascular origin that show lymphatic differentiation
• any age but most often occur in the paediatric population (~90% on those less than 2 years of age
• May present with palpable flank mass and pain
• marked predilection in the head and neck: 95% in the neck and axillary regions
• mesentery, retroperitoneum, abdominal viscera, lung, and mediastinum: ~5%
CT - homogeneous and cystic, but some appear inhomogeneous because of the presence of proteinaceous,
fluid, blood, or fat components within the lesion. minimal or no displacement/compression of adjacent
structures.
MRI - Fluid-fluid levels may be seen if complicated by haemorrhage.
T1: can be variable especially dependent on protein content
T2: usually high signal

44. huge lobular retroperitoneal cystic mass lesion is seen in the right lumbar region, it shows no
contrast enhancement and has imperceptible wall. It extends superiorly to the hepato-renal pouch
and inferiorly to the right broad ligament, right mesorectal fat planes and presacral space. This mass
lesion is displacing the right ureter laterally, the rectum to the left side and the small bowel loops
and pancreas anteromedially and it is seen encasing the ureter and renal vessels

45. Wilm’s Tumor
• also known as nephroblastoma, is a malignant paediatric renal tumour.
• most common pediatric renal mass, accounting for over 85% of cases
• early childhood (1-11 years) with peak incidence between 3 and 4 years of age
• painless upper quadrant abdominal mass. Hematuria is seen in ~20% of cases. HTN due to excess renin
production.
• Associations - Beckwith-Wiedemann syndrome, Perlman syndrome, Simpson-Golabi-Behmel syndrome,
Sotos syndrome, WAGR syndrome, Dennis- Drash syndrome
• arises from mesodermal precursors of the renal parenchyma (metanephros)
• large heterogeneous solid masses which displace adjacent structures; may be cystic.
• Metastases - lung (85%), liver and local lymph nodes. Tumour thrombus into the renal vein, IVC and
right atrium.

46. Imaging
Ultrasound - cystic mass vs solid mass. Tumor thrombus in renal vein and IVC
CT:
heterogeneous soft-tissue density masses with infrequent areas of calcification (~15%) and fat-density regions.
Enhancement is also patchy.
20% of cases have lung metastases at time of diagnosis.
MRI: These tumours appear heterogeneous on all sequences and frequently contain blood products, but
typically are:
T1: hypointense
T1 C+ (Gd): heterogeneous enhancement
T2: hyperintense

49. 8 year old
male

50. 12 year old male with right
renal wilms tumor
NCCT Post contrast

51. Wilms tumor in a 12
year old female
involving left kindney

52. Wilms tumor in a 3-year-old boy with an
abdominal mass. Gadolinium-enhanced
coronal fat-suppressed T1-weighted MR
image shows a large, well-defined mass in the
right kidney (arrows) that enhances less than
adjacent renal parenchyma and contains
multiple hypointense hemorrhagic foci. The
hypointense area in the medial spleen is due
to partial volume artifact.

53. Nephroblastomatosis
• diffuse or multifocal involvement of the kidneys with nephrogenic rests (persistent metanephric blastema).
• Nephrogenic rest are found incidentally in 1% of infants
• persist beyond 36 weeks of gestation and have the potential for malignant transformation into Wilms
tumour.
• Associations - Beckwith-Wiedemann syndrome, hemihypertrophy, WAGR syndrome
• Ultrasound - demonstrate hypoechoic nodules. Diffuse nephroblastomatosis - reniform enlargement with a
thick peripheral rind of tissue that may show striated enhancement with diffusely decreased echogenicity.
• CT - nephrogenic rests appear as low-attenuation peripheral nodules with poor enhancement relative to
that of adjacent normal renal parenchyma.
• MRI
• T1: the nodules demonstrate low-signal-intensity foci
• T2: the nodules demonstrate low-signal-intensity foci
• T1 C+ (Gd): hypointense mass enhances less than renal tissue

56. 12 year old female
with bilateral
nephroblastomatosis
T2WI T1 fat
sat
T1+C

57. Renal Cell Carcinoma
• primary malignant adenocarcinomas derived from the renal tubular epithelium and are the most common
malignant renal tumour.
• accounting for less than 7% of all primary renal tumors manifesting in the first 2 decades of life. Bellini duct
type is most common in pediatric patients.
• associated with von Hippel–Lindau syndrome, in which the tumors tend to be multiple and manifest at a
younger age and can be bilateral.
• Gross painless hematuria, flank pain, and a palpable mass are the most common presenting symptoms.
• tumor invades locally with spread to adjacent retroperitoneal lymph nodes. Metastases to the lungs, bones,
liver, or brain are found in 20% of patients at diagnosis.

58. Imaging
USG - tumour pseudocapsule can sometimes be visualised with ultrasound as a hypoechoic halo
CT:
Corticomedullary phase - enhancement less than that of normal cortex
Nephrogenic phase – heterogeneous enhancement with foci of calcification and hemorrhage. Distortion of
pelvicalyceal system.
Tumor thrombus into renal vein and IVC
MRI:
T1: often heterogeneous due to necrosis, haemorrhage and solid components
T2:
clear cell RCC: hyperintense
papillary RCC: hypointense
T1 C+ (Gd): often shows prompt arterial enhancement

60. 19 year old female with RCC in dysplastic rt
kidney

61. Recurrent RCC in a
17 year old female

62. Renal Nephrometry Score for RCC

64. Mesoblastic Nephroma
• known as a congenital mesoblastic nephroma (CMN) or fetal renal hamartoma) is in general a benign renal
tumour.
• commonest neonatal renal tumour.
• mesenchymal tumour
• . The tumour accounts for ~3-6% of all renal neoplams in children. 50% occur during the neonatal period
and are diagnosed within the first 3 months of life.
• palpable abdominal mass, with haematuria occurring less frequently
• classic mesoblastic and cellular mesoblastic types.
• Associations – polyhydramnios, fetal hypercalcaemia

65. Imaging
USG - well-defined mass with low-level homogeneous echoes; concentric echogenic and hypoechoic rings.
haemorrhage, cyst formation and necrosis; increased vascularity.
CT - Solid hypoattenuating renal lesion with variable contrast enhancement. Cystic areas, necrosis, and
haemorrhage. Typically no calcification seen.
MRI -
T1: iso to hypointense , may show hyperintense foci related to haemorrhage in the cellular subtype
T2: variable, from markedly hypointense to hyperintense
DWI: shows restricted diffusion in the solid portion of the tumour, likely related to increase cellularity

66. Mesoblastic nephroma in a 5-week-old male infant with an in utero renal mass. (a) Longitudinal US scan shows a mass
of mixed echotexture replacing the lower pole of the right kidney (arrows). (b) CT scan shows moderate enhancement

67. Angiomyolipoma of Kidney
• type of benign renal neoplasm and are composed of vascular, smooth muscle and fat elements
• spontaneously haemorrhage, which can be fatal
• Can occur in infants with Tuberous sclerosis; strong female predilection (F:M of 4:1)
• most fat containing lesion of the kidneys
• palpable mass, flank pain, urinary tract infections, haematuria, renal failure, or hypertension
• Associations – Von Hippel-Lindau syndrome, Wunderlich syndrome and NF1
Ultrasound - hyperechoic lesions, located in the cortex and with posterior acoustic shadowing. Tuberous
sclerosis - numerous that the entire kidney is affected, appearing echogenic with the loss of normal
corticomedullary differentiation
MRI - high signal intensity on non-fat-saturated sequences, and loss of signal following fat saturation; in and
out of phase imaging which generates India ink artifact at the interface between fat and non-fat components

68. Mutliple angiomyolipomas in a patient with Tuberous Sclerosis

69. Large angiomyolipoma in left kidney and few smaller ones in right kidney in a patient with
Wunderlich syndrome

70. Multicystic dysplastic Kidney
• type of non-heritable paediatric cystic renal disease
• multiple minute cysts being formed in utero in the affected kidney
• predisposition for the left kidney, a slightly higher incidence in males
• higher incidence in females for bilateral MCDK.
• common cause of renal agenesis
• Types – Pelvi-infundibular and hydronephrotic-obstructive
• Associations – VUR, PUJ obstruction, ureterocele, Zellweger syndrome, Meckel Grber syndrome
• Ultrasound - Lobulated renal contour with multiple internal cysts; the renal parenchyma is usually fibrous
and echogenic with absent or small hilar vessels. Cysts - cluster and are non-communicating.
• MRIs show the typical multicystic appearance of MCDK with little or no parenchyma

71. Fetus at 32 weeks’ gestational age with
multicystic dysplastic kidney. Transverse
ultrasound scan of fetal abdomen shows left
kidney has multiple cysts without
connection between them and without
residual normal parenchyma.

72. T2-weighted MRI scan
demonstrates multiple cysts
without normal renal
parenchyma. A normal left
kidney can be seen on the other
side of the spin

73. Clear Cell sarcoma of Kidney
• mesenchymal tumour that account for ~5% of primary renal neoplasms in paediatric population.
• second most common primary malignant renal neoplasm after Wilms tumour
• The mean age of diagnosis is 3 years, M:F = 2:1
• palpable abdominal mass; with hematuria and bone pain being less common.
• margins of the tumour appear well defined grossly, they demonstrate infiltration in to adjacent renal
parenchyma with entrapment of the tubules
• CT - enhance heterogeneously and to a lesser extent than the adjacent kidney, with non enhancing foci
representing hemorrhage and necrosis . They often cross the midline. Calcification is uncommon.
• MRI - usually appears low to intermediate on T1 weighted images and high signal on T2WI with cystic
areas.

74. Clear cell sarcoma in a 13-month-old girl with an abdominal mass. (a) CT scan shows extensive central
necrosis within a mass arising from the right kidney. (b) CT scan obtained at a higher level shows
heterogeneous enhancement (arrows) with mass effect and hydronephrosis of adjacent calices
(arrowheads)

75. Rhabdoid tumor of kidney
• highly aggressive malignancy of early childhood, closely related to atypical teratoid/rhabdoid tumours
(AT/RT) of the brain.
• exclusively in children, with 60% occurring before the age of 1 year of age, and 80% before the age of 2
years
• haematuria and loin/flank mass
• worst prognosis of all renal tumors.
• rhabdoid tumours appear as large, centrally located, heterogeneous soft-tissue masses, involving the renal
hilum with indistinct margin
CT
• large and heterogenous, usually located centrally within the kidney. haemorrhages or necrosis seen in
between. Enhancement is similarly heterogeneous.
• Linear calcification is relatively common, seen in up to 66% of cases.
• Subcapsular fluid accumulation is a relatively characteristic feature.

76. Rhabdoid tumor in an
8-month-old boy with
hematuria. CT scan
shows a left renal
mass with
heterogeneous
enhancement (arrow)

77. Renal medullary carcinoma
• rare variant of renal cell cancer (highly aggressive malignant tumour of the kidney)
• occurs almost exclusively in adolescent and young adult blacks with sickle cell trait or hemoglobin SC
disease
• range of 10-39 years
• gross hematuria, abdominal or flank pain, and less commonly weight loss, a palpable mass, or fever
• epithelial origin and is thought to arise at the renal pelvic-mucosal interface
• prognosis is extremely poor, with advanced disease at the time of diagnosis
Imaging
• located infiltrative lesion invading the renal sinus with peripheral caliectasis, reniform enlargement, and
smaller peripheral satellite nodules.
• heterogeneous enhancement at CT, and US shows heterogeneous echotexture.

78. Renal medullary carcinoma in a 10-year-old boy with hematuria and sickle cell trait. Longitudinal US scan of the
right kidney shows loss of corticomedullary differentiation and hydronephrotic calices (arrows). Contrast-
enhanced CT scan shows a heterogeneous mass (curved arrows) infiltrating the right kidney and causing
hydronephrosis. Extensive adenopathy is seen surrounding the retroperitoneal vessels (straight arrows)

79. Ossifying renal tumor of Infancy
• rare benign renal mass
• age from 6 days to 14 months
• Boys are more commonly affected than girls
• Hematuria is the most common presenting symptom
• arise from urothelium and is attached to the renal medulla
• seldom more than 2—3 cm in diameter
Imaging
renal outline is usually maintained; Because of its location within the collecting system and its characteristic
ossification, may mimic a staghorn calculus
Ultrasound - calcification; there may be intra-tumoral flow
CT - resemble a staghorn calculus since it originates from the renal papilla, but it enhances on postcontrast.

80. Ossifying renal tumor of infancy in a 2-month-old boy with an abdominal mass. (a)
Nonenhanced CT scan shows a calcification within the left kidney (arrow). (b)
Contrast-enhanced CT scan obtained at the same level shows a low-attenuation
mass (arrows) surrounding the calcification

81. Metanephric adenoma
• benign renal neoplasm
• can present at any age; 2:1 female preponderance
• asymptomatic in many patients. Some patients can have abdominal pain and haematuria.
• Associations – polycythemia
• typically appears as a well-defined, unencapsulated, solitary solid mass
CT - hyperattenuating mass on unenhanced CT; large tumors appear as heterogeneous, hypovascular
masses with frequent foci of hemorrhage and necrosis. Calcification is seen in 20% of cases.
MRI
T1: hypointense signal
T2: usually slightly hyperintense but sometimes hypointense

82. (a) Ultrasonography shows a hypoechoic mass at the lower pole of the right kidney; (b) non-enhanced CT shows an
enlarged right kidney and a slight hyperdense mass. (c) Cortex-, (d) medullary- and (e) delayed-phase CT images
show a hypovascular mass with a well-defined margin and homogeneous density; (f) pathological section shows
densely packed glomeruloid structures (haematoxylin and eosin staining; ×100 original magnification).

84. Lymphoma
• Non-Hodgkin’s lymphoma are most common type
• Burkitt lymphoma is the most frequent subtype of non-Hodgkin's lymphoma in childhood and accounts
for approximately 34% of these cases
• most rapidly growing tumor in children, with a doubling time of approximately 24 hours
• median age of children with Burkitt lymphoma is 8 year
• can involve the head and neck in children, the gastrointestinal tract, genitourinary tract, gonads,
mesentery, peritoneum, and retroperitoneum
• symptoms include abdominal pain, palpable mass, nausea and vomiting, intestinal obstruction due to
bowel compression or intussusception, and acute appendicitis.
• Burkitt lymphoma involving the kidneys can result in renal failure secondary to obstruction or tumor
infiltration of the kidneys

85. Retroperitoneal Burkitt lymphoma in 6 year old male

86. 6-year-old boy with Burkitt
lymphoma. Axial contrast-
enhanced CT image shows
large retroperitoneal mass
encasing major abdominal
vasculature (arrow)

87. Non-Hodgkin large B-cell
lymphoma in a 15-year-old
adolescent girl with
abdominal distention.
Transabdominal US image
shows a well-circumscribed,
heterogeneous, hypoechoic,
solid mass in the ovary. Note
the anechoic small cysts at
the periphery of the mass
(arrows), a finding that
corresponds to preserved
ovarian follicles.

88. Acute lymphoblastic leukemia,
precursor B-cell type, in a 12-year-old
girl with abdominal pain. (a) Sagittal
T2-weighted MR image shows a well-
circumscribed hypointense mass with
peripheral small cysts (arrows) that
represent preserved ovarian follicles. A
focal hyperintense area with a
hemosiderin rim is seen (arrowhead), as
well as ascites (*)

89. Mature Cystic teratoma
• often called dermoid cyst when the ectodermal elements predominate, is the most common ovarian tumor
in children and adolescents, accounting for approximately 50% of all pediatric ovarian neoplasms
• bilateral in up to 10%
• patients may present with abdominal pain, a palpable mass, or acute onset of pain secondary to acute
complications
• USG - cystic mass with a densely echogenic tubercle (a Rokitansky nodule or dermoid plug) that protrudes
into the cystic lumen and shows posterior acoustic shadowing. calcifications or a mixture of hair and
adipose tissue in the tubercle. sebaceous material, multiple thin echogenic bands attributable to hair, fat-
fluid levels, floating debris, or a combination of these features.
• At CT, fat attenuation in a cyst, with or without calcification in the cyst wall or Rokitansky nodule, is the
characteristic finding. A fat-fluid level or a floating mass of hair is occasionally seen .
• At MR imaging, fat - hyperintense on T1-weighted images with signal loss on frequency-selective fat-
saturated T1-weighted images; minimal amount of fat in the cyst wall or Rokitansky nodule and show signal
drop with gradient-echo opposed-phase T1-weighted MR sequences

90. MCT in the right ovary of a 7-year-old girl. (a) Axial transabdominal US image shows a cystic mass with a focal
echogenic nodule (Rokitansky nodule) (arrows) and a posterior acoustic shadow in the dependent portion
(arrowheads) that corresponds to the Rokitansky nodule. Partially echogenic floating debris is also seen (*). (b) Axial
T1-weighted MR image shows a high-signal-intensity focal nodule (arrow) in the posterior wall of the mass. (c) Axial
gadolinium-enhanced fat-saturated T1-weighted MR image shows signal drop in the fatty nodule (arrow) next to the
floating debris (*).

91. Immature Teratoma
• typically affects a younger age group; the younger the patient, the more likely that the teratoma will be
the immature germ cell type
• occurs between the ages of 10 and 20 years, with a median age of 17 years, and represents 10%–20% of all
ovarian malignancies in patients younger than 20 years
• more aggressive behavior and a worse prognosis than does mature teratoma
• usually unilateral, large, and predominantly solid
• Coexisting ipsilateral and contralateral MCTs occur in 26% and 10% of cases of immature teratoma,
respectively
• At CT and MR imaging - large heterogeneous mass with predominantly solid or mixed solid and cystic
lesions. Scattered calcifications throughout the tumor and punctate foci of fat. Hemorrhage is occasionally
seen. Identification of a solid portion with numerous cystic areas is helpful to distinguish immature
teratoma from MCT.

92. Immature teratoma in the ovary of a 12-year-old
girl. Coronal reformatted contrast-enhanced CT
image shows a large mixed cystic and solid mass with
scattered calcifications (arrows) and punctate foci of
fat (arrowheads) in the solid portions

93. Immature teratoma in a 17-year-old girl with abdominal pain. (a) Axial T1-weighted MR image shows a large
ovarian mass (arrows) with multifocal areas of high signal intensity. (b) Axial T2-weighted MR image shows
the mixed cystic and solid components of the mass (arrows). (c) Axial gadolinium-enhanced fat-saturated
T1-weighted MR image shows heterogeneous enhancement of the mass (arrows), which contains cystic
portions. The areas of high signal intensity in a show signal suppression, representing fat components of the
tumor. (d) Gross specimen shows an encapsulated tumor with pink to white solid components, scattered
yellowish fat components, and multiple cystic spaces.

94. Dysgerminoma
• originates from undifferentiated germ cells that are similar to primordial germ cells, and it is identical to
testicular seminoma.
• most common malignant GCT in childhood and adolescence, especially in adolescents aged 15–19 years
• associated with gonadal dysgenesis or abnormal gonads that contain gonadoblastoma
• Associated with Turner syndrome
• highly radiosensitive; The prognosis is usually excellent
Imaging
characteristic imaging appearance of dysgerminoma is a multilobulated solid mass with prominent
fibrovascular septa. Septa appear as hypointense lines on T2-weighted MR images and may show intense
enhancement on contrast-enhanced CT and MR images.
Doppler examination may demonstrate prominent flow signal intensity in the septa
contain necrosis, hemorrhagic foci, or speckled calcifications. spreads to the retroperitoneal lymph nodes

95. Dysgerminoma in an 18-year-old woman with a palpable abdominal mass. (a) Axial transabdominal US image shows
a large mass with relatively homogeneous echogenicity and irregular hypoechoic structures (arrows). (b) Axial
contrast-enhanced CT image shows a large, multilobulated, heterogeneously enhancing mass with linear enhancing
septa (arrows). (c) Photograph of the gross specimen shows a multilobulated solid mass with internal branching septa
(arrows)

96. Dysgerminoma in a 14-year-old adolescent girl. (a) Axial T2-weighted MR image shows a large, multilobulated,
hyperintense solid mass (arrowheads) with linear hypointense septa (arrows). (b) Axial gadolinium-enhanced T1-
weighted MR image shows linear intense enhancement of the prominent fibrovascular septa (arrows) and relatively
homogeneous enhancement of the solid mass (arrowheads)

97. Ovarian embryonal cell
carcinoma
• rare and malignant germ cell tumours of the ovary
• predominantly in children and adolescents (average age 14 years)
• Precocious puberty or menstrual irregularity occurs in 60%. The tumor can secrete B-hcG and/or
AFP.
• unilateral and large, averaging 17 cm.
Imaging - they manifest as a solid mass with areas of cystic change resulting from hemorrhage or
necrosis or a cystic lesion with solid components. Intralesional fat or calcifications may be seen if an
immature teratoma element is present

98. Axial contrast-enhanced CT image shows a
predominantly solid pelvic mass (black
arrows), portions of which have fat
attenuation (white arrows). Areas of soft
tissue with fat loculi are also seen and suggest
immature teratoma; however, histologic
analysis revealed a mixed germ cell tumor
composed of dysgerminoma, immature
teratoma, and yolk sac elements.

99. Gonadoblastoma
• rare tumor composed of germ cells mixed with sex cord derivatives
• arises in dysgenetic gonads in patients with a Y chromosome
• associated with malignant GCT in 25%–50% of cases, especially dysgerminoma
• hormonally active and can manifest with precocious puberty or virilization due to estrogen or androgen
secretion
• US and CT, most macroscopic tumors appear solid. demonstrate mottled or punctuate calcifications at
radiography or CT. Bilaterality is seen in 30%–50% of cases.
• The prognosis is good because pure gonadoblastoma does not metastasize.

100. Gonadoblastoma in an 8-year-old girl with breast development, abnormal vaginal bleeding, and a
normal female karyotype (46,XX). (a) Axial transabdominal US image shows a well-circumscribed
hypoechoic mass in the right ovary (arrows), with a focal cystic portion. (b) Axial gadolinium-
enhanced T1-weighted MR image shows the solid appearance of the mass (arrows), with
homogeneous enhancement.

101. Nongestational Choriocarcinoma
• Type of gonadal germ cell tumors, with pure examples accounting for 2.1%–3.4% of all malignant germ cell
tumor
• Elevated beta HCG, can mimic ectopic pregnancy
• Imaging - well-defined mixed-echogenicity adnexal mass.
• CT features include an enhancing highly vascular solid mass.
• Abnormal large signal voids that represent vascular structures and small cystic cavities are seen in solid
components at T2-weighted MR imaging, and high-signal-intensity foci, a result of hemorrhage, may be
seen in solid portions at T1-weighted MR imaging
• Substantial uptake of gadolinium-based contrast material in solid portions is suggestive of a highly
vascularized tumor.

102. Ovarian nongestational choriocarcinoma in a 17-year-old woman who presented with a palpable pelvic
mass and β-hCG level of 217,000 mIU/mL. Coronal T1-weighted (a), sagittal T2-weighted (b), and axial
contrast-enhanced T1-weighted gradient-echo (c) MR images show a large pelvic mass (arrows) that is
slightly hypointense relative to muscle on T1-weighted images and small cystic cavities that are best seen
on T2-weighted images. Soft-tissue septa (arrowheads) between the cystic cavities demonstrate
enhancement on contrast-enhanced images.

103. Sacrococcygeal teratoma
• teratoma arising in the sacro-coccygeal region. The coccyx is almost always involved
• commonest congenital tumour in the fetus and neonate. M:F=1:4
• arise from totipotent cells from the node of Hensen; composed of the all three germ cells
• Associations – myelomeningocoele, vertebral anomalies
• elevated levels of alpha feto protein (AFP), beta HCG
• Can be benign (mature) or malignant
Plain film - may show a large mass projecting from the lower pelvic region or within the
abdominopelvic cavity
may show calcification

104. Ultrasound
• Mature types tend to be more cystic which show as anechoic components. Solid types (which are much
rarer) often show an echogenic mass within the pelvis.
• tumours may show marked hypervascularity with arterio-venous (AV) shunting.
MRI
T1: fat components appear high signal, calcific/bony components low signal
T2: fluid (cystic) components appear high signal, calcific bony components low signal
T2* GRE: magnetic susceptibility artifact because of calcifications
T1 C+ (Gd): enhancing solid components
• colonic displacement, ureteric dilatation, associated hip dislocation, intraspinal extension, vaginal
dilatation
• metastatic assessment in malignant lesions

108. T2WI STIR T1+C

109. Conclusion
• Imaging plays an important role in the diagnosis and management.
• Plain radiographs provide clues to the location of the mass,organomegaly and the presence of
calcifications.
• Ultrasound is generally the most valuable procedure for the initial evaluation.
• Ultrasound differentiates cystic from solid masses, indicates the organ of origin, and suggests the
diagnosis, also about the vascular compromise and intraluminal thrombosis.
• CT or MR needed when the mass is large, poorly defined, for staging or when obscured by
bowel gas.
• Radionuclide for specific applications
• Hence a radiologist must have comprehensive understanding of various retroperitoneal anomalies
to reach a better diagnosis and guide the management of patient’s condition.

110. Thank You