Solid tumors

Question 1

Brain tumors (pituitary/sellar)- craniopharyngioma

Answer 1

Craniopharyngoma
Solid/cystic tumor (sellar mass) arising from remnant of Rathke’s pouch (nasopharynx to diencephalon) forms within sella turcica or along pituitary stalk
- Most have large suprasellar component, most involve both spaces, rare to be just intrasellar

Epidemiology
7-10% of all childhood tumors
Peak incidence 5-14yrs (50% present within childhood)
3rd most common after glioma & medulloblastoma
CTNNB1 mutation

• *Clinical manifestations**
  1. Endocrinological: due to compression
• growth failure, GH = 75%, (short stature, elated puberty)
• hypogonadism, GnRH = 40%,
• hypothyroidism, TSH = 25% (fatigue, low mood, myxedema)
• adrenal insufficiency, ACTH = 25% (fatigue, low BP, electrolyte abnormalities)
• diabetes insipidus (polyuria, polydipsia)
  2. Eyes: bitemporal hemianopia in 70%, loss of acuity, papilloedema, optic nerve compression (direct effect)
  3. CNS: headache (dull/continuous, positional) and vomiting
• Large tumors can lead to obstructive hydrocephalus

Ix:
Lateral skull XR- calcification
MRI: heterogenous mass with solid/cystic components, suprasellar epicentre with calcifications
Visual field testing

Endocrine function tests- GH, GnRH, TFTs, ACTH

DDx: other sellar masses, meningioma, glioma, teratoma, benign cysts
1. Pituitary adenoma
→ 50% occur in adolescence (rare in childhood) and are associated with MEN1 syndromes
→ Epicentre intrasellar, absent calcification, elevated prolactin,
→ secretory most common, ACTH then GH
→ causes growth arrest, pubertal delay, amenorrhoea, hypogonadism
→ Rx trans-sphenoidal pituitary adenectomy, dopamine agonist/bromocriptine to reduce size/PRL levels

2. Benign Rathke cyst- no solid/enhancing component, mostly intrasellar

• *Rx:** surgical removal, post surgical radiotherapy if residual disease (risk of meningioma/glial tumor)
• Treatment related morbidity hypopituitarism (adrenal insufficiency, hypogonadism and hypothyroidism), hypothalamic dysfunction (poor weight, sleep & temperature regulation, DI)

Prognosis: 50-90% 5 year survival

Question 2

Brain tumors- common clinical presentations

Answer 2

• *Infants**
• Vomiting
• Irritability, lethargy
• Raised head-circumference/macrocephaly
• Bulging fontanelle
• *Older children**
• Above
• Headaches
• Early morning vomiting
• Visual changes- diplopia, abnormal eye movements, strabismus
• Seizures
• Change in personality/’behavioral difficulties’/’learning difficulty’
• UL/LL sensorimotor changes
• Changes in gait, ataxia
• Torticollis
• Delayed growth/puberty
• *By tumor type/region**
  1. Raised ICP: vomiting, lethargy, macrocephaly, papilledema, sunsetting eyes (reduced vertical eye movements)

2. Midline 10-15%
   - headache (new onset, persistent) + N&V + papilloedema
3. Posterior fossa/infratentorial (cerebellum) 50-60%
   - truncal ataxia, disequilibrium, poor co-ordination
   - CN palsies (II- diplopia, VII- facial droop)
   - tonsillar herniation → torticollis
4. Brainstem
   - gaze palsy, other CN palsies
   - UMN signs (hemiparesis, hyperreflexia, clonus)
5. Supratentorial (cortical) - 30-50%
   - changes to speech/personality
   - lateralized defects - sensory, motor, seizures, reflex asymmetry
   - premature hand preference
6. Optic pathway
   - visual defects- decreased acuity, hemianopias
   - RAPD, marcus gunn pupil, nystagmus
7. Suprasellar/third ventricle
   - Endocrine (hypothyroid, gonadism, pituitarism, adrenals)- galactorrhoea
   - Obesity, abnormal sleep & temperature regulation
   - Di-encephalic syndrome = failure to thrive + emaciation despite normal caloric intake + inappropriately normal or happy affect (anterior hypothalamus)
8. Pineal tumors
   - parinaud syndrome = paresis of upward gaze, pupillary caliber reactive to accommodation but not to light (pseudo Argyll Robertson pupil), nystagmus to convergence or retraction, and eyelid retraction
9. Spinal tumors
   - motor/sensory defect below level of nerve root
   - radiculopathies
10. meningeal: head or back pain, neurology if compression

Question 3

Brain tumors- overview

Answer 3

• *Epidemiology**
• Most common solid malignancy, 20-25% of all paediatric tumors
• Mortality 30-75% 5 year survival, highest morbidity
• Incidence highest in <5yrs

Etiology poorly defined

• M>F (especially medulloblastoma/ependymoma)
• Syndromic/familial 5% of brain tumors
• Associated w ionising radiation

Question 4

Outline diencephalic syndrome

Answer 4

Diencephalic syndrome (Russel’s syndrome)

• Uncommon cause of FTT in early childhood associated with CNS neoplasms in the hypothalamic-optic chiasmatic region
• The classical symptoms relate to hypothalamic dysfunction
• Clinical features
  
  • Profound emaciation despite normal or slightly diminished caloric intake
  • Intact linear growth
  • Hyperalertness, hyperkinesia, euphoria
  • Nystagmus
  • Hydrocephalus
  • Visual field defects
• Onset is almost always within the first 3 years of life
• Tumor type: most commonly astrocytoma (pilocytic or pilomyxoid)