Introduction
Childhood cancer is rare (about 1 child in 500 before 15 years) but is still a leading cause of death from disease in children. After leukaemia, the commonest are brain tumours (the commonest solid tumours, about 20–25%), lymphomas, neuroblastoma, Wilms tumour, soft-tissue and bone sarcomas, retinoblastoma and germ cell tumours. Children's tumours are mostly embryonal, grow fast and respond well to treatment: about 80% are cured.
Brain tumours
In children, more than half are below the tentorium (cerebellum, brainstem), unlike adults.
- Pilocytic astrocytoma: cerebellar, cystic, low grade; surgery often cures.
- Medulloblastoma: the commonest malignant brain tumour; cerebellar vermis, blocks CSF flow; spreads through CSF; surgery, craniospinal radiotherapy (over 3 years), chemotherapy; molecular groups (WNT best, SHH, groups 3 and 4).
- Ependymoma: fourth ventricle. Diffuse midline glioma (DIPG): brainstem, cranial nerve palsies and ataxia, almost always fatal.
- Craniopharyngioma: above the sella, calcified; headache, bitemporal hemianopia, short stature, diabetes insipidus.
Neuroblastoma
From neural crest cells of the adrenal medulla or sympathetic chain; the commonest cancer in infants. Signs depend on spread: abdominal mass, bone pain and limp, periorbital bruising (orbital metastases), skin nodules (“blueberry muffin”), Horner syndrome, spinal cord compression, opsoclonus–myoclonus, watery diarrhoea (VIP). MYCN amplification means high risk. Some infant tumours (stage MS, formerly 4S) regress by themselves. Treatment ranges from observation to intensive chemotherapy, surgery, stem cell transplant, radiotherapy and anti-GD2 antibody.