paediatric oncology Flashcards
What is a retinoblastoma?
the most common ocular malignancy in children
What age does retinoblastomas usually present?
18 months
Aetiology of retinoblastoma
autosomal dominant condition caused by a loss of the tumour suppressor gene found on chromosome 13
Presentation of retinoblastoma
absent red reflex - most common presenting symptom
strabismus
visual problems
bulging in one eye
red painful eye
How are retinoblastomas diagnosed?
fundus photography
Fluorescein angiography
Ophthalmic USS- gold standard
MRI
How are retinoblastomas treated?
initial management may involve- external beam radiation, chemotherapy and photocoagulation.
In unsuccessful may need enucleation (removal of the eye)
Where do neuroblastomas arise from
the neural crest cells of the adrenal medulla or the sympathetic nervous system
What is the median age of onset of neuroblastomas
20 months
how do neuroblastomas present?
blueberry muffin rash - from seeding metastasis in the dermis.
abdominal mass
pallor
weight loss
bone pain and limp
hepatomegaly
paraplegia
proptosis
signs of increased catecholamine secretion -sweating, agitation
What is the peak age of acute lymphoblastic leukaemia
2-3 years
How are neuroblastomas diagnosed?
raised urinary vanillymandelic acid (VMA) and homovanillic acid (HVA) levels
USS or MRI
calcifications seen on X ray
Definitive test= MIBG scan (radioactive isotope injected and 2 scans taken 24 hours apart- iodine will stay in tumour)
Gold= biopsy
What is the most common leukaemia in children
acute lymphoblastic leukaemia
What leukaemias are common in children
acute lymphoblastic
acute myeloid
chronic myeloid leukaemia
risk factors for leukaemia
radiation exposure during pregnancy
Down’s syndrome
Kleinfelter’s syndrome
Noonan syndrome
Fanconi anaemia
pathophysiology of leukaemia
A cancer of the bone marrow- a genetic mutation leads to excessive production of a single blood cell
Leads to supression of all the other types of blood cells- pancytopenia
How does leukaemia present?
general symptoms- anorexia, malaise, fever
bone marrow infiltration symptoms- pancytopenia (anaemia- lethargy, pallor; neutropenia- infection; thrombocytopenia - bruising, petechiae, epistaxis)
bone pain
reticulo-endothelial infiltration symptoms- hepatosplenomegaly, lymphadenopathy, superior mediastinal obstruction
symptoms of other organ infiltration - CNS, testes, mediastinal mass
differentials for anaemia
viral infection
EBV infection
parvovirus
ITP,
aplastic anaemia
how is leukaemia diagnosed
FBC- pancocytopenia
blood film- blast cells
bone marrow biopsy
lymph node biopsy
CT, chest x ray
what is the most common malignant bone tumour in children
osteosarcoma
two types of paediatric bone tumours
osteosarcoma and ewings sarcoma
What is wilms tumour
a type of kidney tumour that typically affects children under 5
what age group is most commonly affected by wilms tumours
children under 5- mean age is 3
what genetic conditions are associated with wilms tumours (particularly if bilateral)
WAGR syndrome
Beckwith- Wiedemann syndrome
hemihypertrophy
How does wilms tumour present?
abdominal mass
painless haematuria
flank pain = rare
anorexia
fever
weight loss
Where does wilms tumour most commonly metastasise?
lung
what genetic mutation is associated with wilms tumour
loss of function of the WT1 gene on chromosome 11
Diagnosis of wilms tumour
1st line- USS abdo
gold- biopsy
How quickly should children presenting with an unexplained abdominal mass be reviewed in paediatrics
within 48 hours
how is wilms tumour treated?
nephrectomy
chemotherapy
radiotherapy if advanced
what is the prognosis of wilms tumour
80% cure
what two bone tumours are most common in children?
osteosarcoma (most common)
Ewings sarcoma
what age group is typically affected by osteosarcomas?
aged 10-20
what mutation is associated with osteosarcomas
a mutation in the Rb gene
what conditions increase the risk of osteosarcomas?
Paget’s disease
radiotherapy
Li-Fraumeni syndrome
what mutation is associated with Ewing’s sarcoma
t(11:22) translocation which results in a EWS-FLI1 gene product
where in the bone do most osteosarcomas occur
in the metaphyseal region of long bones before closure of the epiphyseal plate
what bones are most commonly affected in osteosarcomas?
femur - 40%
Tibia- 20%
Humerus - 10%
what cells are osteosarcomas derived from
the primitive transformed cells of mesenchymal origin
What bones do Ewing’s sarcomas commonly effect?
pelvis and long bones
What type of tumour is Ewing’s sarcoma
neuroectodermal tumour
How doe bone tumours in children present?
persistent bone pain- often worse at night and can wake them up from sleep
May have bone swelling, a palpable mass and restricted joint movement
How are bone tumours diagnosed
X ray- NICE recommends within 48 hours of child presenting with unexplained bone pain or swelling
Bloods- raised ALP
CT/MRI for staging
Bone biopsy is definitive
How does a osteosarcoma present on X ray
Codman triangle and a ‘sunburst’ pattern
May show a poorly defined lesion in the bone with fluffy appearance
How does Ewing’s sarcoma present on X ray
onion skin appearance
what is the most common type of brain tumour found in children ?
astrocytomas
What is the most malignant cancer found in children
medulloblastomas
what cells do meningiomas arise from
arachnoid cap cells of the meninges
histopathology of medulloblastoma
small blue cells in a rosette pattern with many mitotic figures
histopathology of astrocytomas
rosenthal fibres (corkscrew eosinophilic bundles)
histopathology of meningiomas
spindle cells in concentric whorls and calcified psammoma bodies
