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CNS tumorAwaiting clinical review

Pediatric CNS tumors

The most common solid tumors of childhood: morning headache with vomiting, and a posterior fossa that explains most of the exam findings.

Most common site
Posterior fossa (infratentorial)
Most common tumor overall
Pilocytic astrocytoma
Most common malignant
Medulloblastoma
Radiation age caution
Avoided when possible under 3 years

The presentation you must not miss

  • Headache worst on waking, morning emesis that relieves the headache, then new ataxia, diplopia, or a head tilt.
  • Infants: macrocephaly, bulging fontanelle, sunsetting eyes, developmental regression.
  • Parinaud syndrome (upgaze palsy, light-near dissociation) points to a pineal region mass.
  • Bitemporal hemianopsia plus growth failure points to craniopharyngioma (calcified suprasellar mass) or optic pathway glioma (think NF1).

Do not miss

  • Signs of raised intracranial pressure with a posterior fossa mass: obtain neurosurgical evaluation urgently; lumbar puncture can precipitate herniation.
  • New-onset unexplained morning vomiting in a child without diarrhea deserves a neurologic exam and a low threshold for imaging.

Know these four

  • Pilocytic astrocytoma: cystic with a mural nodule, Rosenthal fibers, cured by gross total resection; NF1 association.
  • Medulloblastoma: midline cerebellar/vermis, small round blue cells, drop metastases through CSF — stage the whole spine and sample CSF.
  • Ependymoma: arises from the fourth ventricle floor and extrudes through foramina ('plastic tumor'); perivascular pseudorosettes; extent of resection drives outcome.
  • Diffuse midline glioma (H3 K27M-altered, formerly DIPG): pontine, cranial nerve palsies with long-tract signs, radiation is palliative — this is the conversation about goals of care.

After treatment

  • Posterior fossa syndrome (cerebellar mutism) can appear 1–2 days after resection and is frightening for families; it usually improves slowly over months.
  • Cranial radiation in young children costs IQ points, growth hormone, thyroid function, and fertility — this drives proton therapy and radiation-sparing strategies.
  • Endocrine surveillance is lifelong after any hypothalamic-pituitary axis exposure.

Pearls

  • Morning headache + vomiting + ataxia in a school-age child = posterior fossa tumor until imaged.

  • Do not LP before imaging when raised ICP is possible.

  • NF1 → optic pathway glioma; tuberous sclerosis → subependymal giant cell astrocytoma; both change the surveillance plan.

On the ward

  1. 1Document a focused neuro exam every shift, including gait if the child can walk safely.
  2. 2Know whether the child has an external ventricular drain or shunt and the parameters for it.
  3. 3Confirm steroid dosing and taper plan for peritumoral edema.
  4. 4Ask whether school and neuropsychology referrals are in place before discharge.

2 vignette questions on this topic.

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Sources

  • Children's Oncology Group — Protocol families and risk stratification frameworks used across US pediatric centers.
  • NCCN Guidelines (Pediatric) — US consensus guidance on treatment and supportive care pathways.