Neuroblastoma

• Neuroblastoma (NB) is an embryonal tumor of the peripheral sympathetic nervous system.
• First described by Rudolf Virchow as "abdominal glioma" in 1864.
• Felix Marchand (1891) determined their origin to be from the sympathetic nervous system and adrenal medulla.
• William Pepper first discovered stage 4s in 1901.
• James Homer Wright (1910) named it “Neuroblastoma.”
• Classical histological finding – Homer Wright pseudorosette.
• It is one of the small, blue, round cell tumors of childhood (e.g., Rhabdomyosarcoma, Ewing sarcoma, non-Hodgkin lymphoma).
• It is an embryonal tumor of the peripheral nervous system.
• A spectrum of neuroblastic tumors that arise from primitive sympathetic ganglion cells.
• Exhibits heterogeneous clinical presentation and course.
• It is of neural crest cell origin.
• Most commonly originates from the adrenal gland, and nerve tissues in the neck, chest, abdomen, and pelvis.

• Almost exclusively a disease of childhood.
• It is the third most common pediatric tumor, accounting for about 8% of childhood malignancies.
• It is the most common malignancy of infancy, accounting for 28-39% of neonatal malignancies.
• It is the most common extracranial solid tumor of childhood.
• The median age at diagnosis is 2 years; 90% of cases are diagnosed before 5 years of age.
• The incidence is slightly higher in males (1.7:1) and in whites.
• Accounts for 7% of childhood malignancies.
• At diagnosis, 75% of cases are under 4 years.
• Peak incidence at 2 years.

• Neuroblastoma (NB) includes a spectrum of tumors with variable degrees of neural differentiation, ranging from undifferentiated small round cells to those containing mature ganglion cells (e.g., ganglioneuroblastoma or ganglioneuroma).
• The genetic event that initially triggers the formation of NB is not known.
• It is likely related to a succession of mutational events, both prenatally and perinatally, that may be caused by environmental and genetic factors.
• The precise genetic event that triggers neuroblastoma is not known.
• Gene amplification:
• N-MYC oncogene amplification
• Tumor suppressor inactivation
• Alterations in gene expression
• Tumor cell DNA content
• Genetic malformations involving loss of 1p, 11q, and 14q and gain of 17q have been demonstrated in neuroblastoma tissue.
• Other factors implicated include:
• Tumor histology
• Vascularity
• Nerve growth factor receptors
• Ferritin
• Lactate dehydrogenase
• Ganglioside
• Neuropeptide
• CD 44
• Telomere
• Spread is via hematogenous route.

• Grossly, the tumor is nodular.
• It ranges in size from minute nodules to large masses (>1 kg).
• On transection, they are composed of soft, grey-tan, brain-like tissue.
• Larger tumors may have areas of necrosis, cystic softening, and hemorrhage. Occasionally, punctate calcification can be palpated.
• Histologically, small, primitive-appearing cells with dark nuclei, scanty cytoplasm, and poorly defined cell borders grow in solid sheets with a faintly eosinophilic fibrillary background (small round blue cell).
• Typically, rosettes (Homer-Wright pseudorosettes) can be seen.

Sites

• 75% - Retroperitoneal
• 50% - Adrenal medulla
• 25% - Paraspinal ganglia
• 20% - Posterior mediastinum
• 5% - Neck and pelvis

Macroscopy

• Purple, highly vascular, and friable.
• Becomes nodular as it matures or responds to therapy.

Microscopy

• Composed of neuroblasts – small round cells with prominent nuclei and small cytoplasm.
• Immature tumors have no special arrangement of cells.
• More mature tumors show rosette formation; some may resemble normal ganglion cells.
• Electron microscopy shows neurofibrils and electron-dense granules, ruling out PNET, rhabdomyosarcoma, and Ewing's tumor.

• Unknown
• Majority are sporadic.
• These tumors arise from primordial neural crest cells, which ultimately populate the sympathetic chain and the adrenal medulla.
• Most neuroblastomas produce catecholamines, such as Vanillymandelic acid (VMA) and Homovanillic acid (HVA), and vasoactive intestinal peptides as metabolic by-products.
• Familial in 1-2% of cases:
• Autosomal dominant
• Incomplete penetrance
• Broad spectrum of clinical behavior
• Earlier median age of diagnosis (9 months)
• Bilateral or multifocal disease
• Disruption of a locus at 16p12-13
• No sibling affectation except for multiple affected individuals
• Mutations in PHOX2A, KIF1B, and ALK genes.
• Increased incidence of NB is associated with certain maternal and paternal occupational chemical exposures, work in farming, and work related to electronics.

• Maternal factors:
• Opiate consumption
• Folate deficiency
• Toxic exposure (e.g., hair dye, hormones, fertility drugs)
• Congenital abnormalities
• Gestational diabetes mellitus
• Genetic factors:
• Turner syndrome
• Hirschsprung disease
• Central hypoventilation syndrome
• Neurofibromatosis type I
• Beckwith-Wiedemann syndrome

International Neuroblastoma Staging System (INSS)
Stage	Description
Stage 1	Tumor confined to structure of origin
Stage 2A	Tumor extends beyond structure of origin but does not cross the midline without ipsilateral node involvement
Stage 2B	Tumor extends beyond structure of origin but does not cross the midline with ipsilateral node involvement
Stage 3	Tumor extends beyond the midline with or without bilateral node involvement
Stage 4	Distant metastasis to bone, distant nodes, bone marrow, liver, skin
Stage 4S (infants <1yr)	Primary tumor as in stages 1 and 2 with dissemination limited to the skin, liver, and/or bone marrow

Reflects the location of the mass and the extent of metastasis. Can arise anywhere along the sympathetic ganglia.

• Most cases arise in the abdomen, either in the adrenal gland or in retroperitoneal sympathetic ganglia.
• Usually presents as a firm, nodular mass palpable in the flank or midline, causing abdominal discomfort.

Clinical Symptoms

• Systemic symptoms:
• Fever
• Weight loss
• Asymptomatic mass
• Abdominal mass:
• The mass is usually in the lumbar region, may cross the midline, is hard, nodular, and slow-growing. The kidney is often displaced downwards.
• Can be an incidental finding
• May be retroperitoneal or hepatic
• Abdominal pain or fullness
• Constipation
• Anorexia
• Distention
• Scrotal or lower extremity edema
• Intestinal obstruction

Abdominal mass
×
Abdominal mass
• Pelvic mass:
• Spinal cord compression with localized back pain and weakness
• Bladder dysfunction/reduced bladder capacity
• Thoracic tumor:
• Tracheal deviation with respiratory distress (mediastinal tumor)
• Horner syndrome
• Superior vena cava syndrome
• Cervical mass:
• Horner syndrome
• Heterochromia iridis

Extent of the Metastasis

• Orbit and eyes:
• Orbital secondaries with periorbital hemorrhage (“raccoon eyes”)
• Proptosis
• Periorbital ecchymosis

Orbital secondaries
×
Orbital secondaries
• Skin:
• Palpable, non-tender, bluish subcutaneous lesions
• Neonates with disseminated neuroblastomas may present with multiple cutaneous metastases with deep blue discoloration of the skin – the so-called “blueberry muffin baby”

blueberry muffin baby
×
blueberry muffin baby
• Regional lymph node enlargement

• Liver:
• Abdominal distention
• Respiratory distress
• Bone:
• Bone pain/joint pain
• Cytopenias
• Anemia
• Fever
• Limp
• Unexplained irritability

Other Clinical Features

• Paraneoplastic syndrome:
• Opsoclonus myoclonus ataxia
• Secretion of vasoactive intestinal peptide
• Abdominal distention
• Secretory diarrhea
• Hypokalemia
• Catecholamine secretion:
• Hypertension
• Increased sweating
• Stage 4S:
• Widespread subcutaneous nodules
• Massive liver involvement
• Limited bone marrow disease
• Small primary tumor without bone involvement

• Pepper syndrome: Liver metastasis with or without respiratory distress
• Hutchinson syndrome: Limping and irritability in a child with bone metastasis
• Neurocristopathies: Hirschsprung disease, central hypoventilation syndrome
• Kerner Morrison syndrome: Intractable diarrhea
• Opsoclonus Myoclonus Ataxia: Immune mediated
• Horner syndrome: Unilateral ptosis, miosis, and anhidrosis

Laboratory Tests:

• Full Blood Count (FBC)
• Blood Grouping and Cross-Matching
• Serum Chemistry
• Liver Function Tests
• Electrolytes, Urea, and Creatinine
• Serum Ferritin and Lactate Dehydrogenase (LDH)

Imaging Studies:

• Chest X-Ray (CXR)
• Intravenous Urography (IVU)
• Abdominal Ultrasound (ABD USS)
• Computed Tomography (CT) Scan
• Magnetic Resonance Imaging (MRI)

Bone Scan:

• Radionuclide Scan
• Methylenediphosphonate Bone Imaging (MBIG)
• Bone X-Ray

Tumor Markers:

• Urinary Vanillylmandelic Acid (VMA)
• Urinary Homovanillic Acid (HMA)

Bone Marrow Examination:

• Bone Marrow Biopsy
• Electron Microscopy
• Immunohistochemistry

Additional Tests:

• Electrocardiogram (ECG)
• Echocardiogram (ECHO)

Prenatal Diagnosis

• Prenatal Ultrasound
• Urinary tumor markers

Diagnostic Criteria

• An equivocal histologic diagnosis from primary tumor tissue with or without the following:
• Immunohistochemistry
• Electron microscopy
• Increased urine/serum catecholamine
• Evidence of metastasis to bone with concomitant elevation of urinary/serum catecholamine

Varies with location:

Abdominal Mass:

• Hepatoblastoma
• Nephroblastoma
• Burkitt lymphoma
• Abdominal TB

Pelvic Mass:

• Ovarian mass

Thoracic Involvement:

• Lymphoma
• Germ cell tumor
• Infection

Bone Marrow Secondaries:

• Lymphoma
• Small cell osteosarcoma
• Chondrosarcoma
• Ewing sarcoma
• Rhabdomyosarcoma
• PNET
• Leukemia

Secretory Diarrhea:

• Factitious
• Enterotoxin
• Vipoma
• Carcinoid syndrome
• Gastrinoma
• Rectal villous adenoma
• Bile salt enteropathy

Spinal Canal:

• Dermoid
• Epidermoid
• Teratomas
• Astrocytomas

Skin Nodules:

• Dermoid cyst
• Benign tumors
• Congenital leukemia
• Rhabdomyosarcoma
• Subcutaneous fat necrosis

Associations of Opsoclonus Myoclonus Ataxia Syndrome:

• Hepatoblastoma
• Infections: HIV, Lyme, Syphilis, Polio, Rickettsia, etc.
• Ingestions: Cocaine, Lithium, Diazepam, Phenytoin
• Toxic exposure: Toluene, Thallium, Organophosphate, Strychnine
• Metabolic derangement: HHS, Carboxylase deficiency

Differences between neuroblastoma and nephroblastoma
Neuroblastoma	Nephroblastoma
Embryonal malignancy from primitive neuroblast	Embryonal malignancy from nephrogenic tissue
Arise from any part of the sympathetic chain	Arise from kidney only
No other abnormality	WAGR
Mass often crosses midline	Does not cross midline
Presence of other masses aside from abdomen	Abdominal mass
Associated chronic diarrhea	Absent
Maybe associated with cord compression syndrome	Absent
Horner syndrome may be present	Absent
Hypertension less common	Hypertension common
Maybe associated with opsoclonus-myoclonus syndrome	Absent
Metastasis to bone	Metastasis to lungs
Advanced stage 4s may regress spontaneously	Advanced stage does not regress
Increased LDH	Normal
Increased ferritin	Normal
Increased vasoactive intestinal peptide	Normal
Increased HVA/VMA	Normal
Hematuria absent	Microscopic hematuria
Slight male preponderance	Equal in both sexes
Normal pelvicalceal system but displaced inferiorly	Intrarenal mass
Extra-renal mass	Distorted pelvi-calceal system
Prognosis depends on histologic stage and stage	Mainly on age and stage of the tumor
17q	11p

• Multimodal Multidisciplinary Approach:
• Paediatric oncologist/paediatrician
• Paediatric social workers
• Nurses
• Child psychologist
• Psychiatrist
• School teachers
• Child life specialist
• Discuss treatment plan with patient and family
• Treatment tailored to pathologic risk classification

• Localized Disease: Can be totally excised
• Advanced Disease: Surgery is not helpful
• Combination Cytotoxic Therapy: Useful in advanced neuroblastoma cases, using:
• Vincristine
• Cyclophosphamide
• Cisplatin
• Doxorubicin

Child Oncology Group Neuroblastoma Risk Stratification

• Based on: INSS stage, age of patient, ploidy, N-MYC status, and histology using Shimada et al. classification
• The aim was to reduce therapy for low and intermediate risk neuroblastoma while maintaining a survival rate at 90%
• Intensive treatment was targeted at the high-risk group

Tumor-Specific Complications

• Metabolic:
  • Tumor lysis syndrome
• Hematologic:
  • Disseminated intravascular coagulopathy
  • Anemia
  • Thrombocytopenias
  • Neutropenia
  • GVHD (Graft-versus-host disease)
• Space Occupying Lesion:
  • Spinal cord compression
  • SVC (Superior vena cava) syndrome
  • Trachea deviation

Treatment-Related Complications

• Nausea, vomiting, anorexia
• Vascular injury to kidney
• Renal atrophy
• Multiple endocrine effects:
  • Growth reduction
  • Infertility
  • Thyroid dysfunction
• Secondary malignancies
• Scoliosis
• Anthracycline-induced cardiotoxicity
• Alopecia
• Psychological problems
• Platinum-related:
  • Ototoxicity
  • Neurotoxicity
  • Nephrotoxicity

Variable	Favorable	Unfavorable
Age	<1 yr	>1 yr
Stage	1, 2a, 2b, 4s	3, 4
Histology	Schwannian stroma and ganglionic differentiation	Absent
Mitotic rate	Low	High
Mitosis-karyorrhexis index	<200/5000 cells	>200/5000 cells
Intertumoral calcification	Present	Absent
DNA ploidy	Hyperdiploid or near triploid	Diploid or near diploid or near tetraploid
N-myc	Not amplified	Amplified
X 17q gain	Absent	Present
X 1p loss	Absent	Present
Trk-A expression	Present	Absent
Telomerase expression	Low or absent	High
MRP expression	Absent	Present
CD44 expression	Present	Absent
Serum biochemical markers	Ferritin Normal Lactate <1500 U/ml	Ferritin Elevated Lactate >1500 U/ml
Heterozygosity	Present	Loss

5 Year Event Free Survival Rate
Stage of the Tumor	EFSR (%)
Stage 1	81-98%
Stage 2	90-95%
Stage 3	40-60%
Stage 4	20-30%
Stage 4s	>90%; close to 100%

• No specific environmental exposure or risk factors have been identified
• Currently, no specific recommendation on protective measures
• Early Diagnosis and Treatment:
  • Screening has uncovered more patients with neuroblastoma but has not shown an effect on outcome
• Limitation of disability
• Rehabilitation
• Surveillance, monitoring, and evaluation