Brain Tumor in Newborn/Infant

Susan I. Blaser, MD, FRCPC

DIFFERENTIAL DIAGNOSIS

Common

Anaplastic Astrocytoma
Teratoma
Medulloblastoma (PNET-MB)
Supratentorial PNET
Supratentorial Ependymoma
Choroid Plexus Papilloma

Less Common

Subependymal Giant Cell Astrocytoma
Desmoplastic Infantile Ganglioglioma
Desmoplastic Infantile Astrocytoma
Glioblastoma Multiforme

Rare but Important

Choroid Plexus Carcinoma
Atypical Teratoid-Rhabdoid Tumor
Neurocutaneous Melanosis (Melanoma/Melanocytoma)
Pineoblastoma
Brainstem Glioma, Pediatric
Medulloepithelioma

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Newborn/infant brain tumors
- Typically large, bulky, inhomogeneous
- Supra- > infratentorial (infratentorial more common in older children)

Helpful Clues for Common Diagnoses

Anaplastic Astrocytoma
- Infiltrating mass, predominantly white matter (WM)
  - Hemispheric WM (frontotemporal)
- Ca++ rare; heterogeneous on MR
- No or variable enhancement
  - Ring enhancement, bleed, necrosis, flow voids suggest GBM
Teratoma
- Midline, supratentorial
- Small lobular or holocranial
- Contents
  - Ca++, cysts, fat
  - Enhancing soft tissue
- Look for associated congenital brain anomalies
Medulloblastoma (PNET-MB)
- 4th ventricle mass with hydrocephalus
  - Restricts on DWI (best MR clue)
  - Sparse Ca++ ≈ 20%
  - Enhancement usual (may be late/slow)
  - Hemorrhage rare
- Hypercellularity reflected on imaging
  - Hyperdense (NECT), hypointense (T2)
- Medulloblastoma with extensive nodularity
  - Subtype with expanded lobular architecture
  - Grape-like enhancement
  - Better prognosis
Supratentorial PNET
- Large complex mass
  - Restricts on DWI (differentiates from ependymoma)
  - Heterogeneous signal, enhancement
  - Ca++ more common than in posterior fossa PNETs
  - Hemorrhage, necrosis common
- Hemispheric
  - Mean diameter 5 cm
  - Especially newborn/infants
  - Minimal peritumoral edema
- Suprasellar
  - Early neuroendocrine, visual disturbances
- Pineal (pineoblastoma)
  - Hydrocephalus, Parinaud syndrome
Supratentorial Ependymoma
- Peri/extraventricular > intraventricular
  - Periventricular ependymal rests
  - Large, bulky
  - Ca++ ≈ 50%
  - Variable necrosis, hemorrhage
Choroid Plexus Papilloma
- CPP: Lobulated intraventricular mass
  - Lateral > 4th > 3rd
  - NECT: Iso- to dense
  - Iso- to slightly hyperintense on T2WI
  - Vividly enhancing
- Hydrocephalus common

Helpful Clues for Less Common Diagnoses

Subependymal Giant Cell Astrocytoma
- Enhancing mass near foramen of Monro
- Found in tuberous sclerosis complex
- Look for
  - Subependymal Ca++ nodules
  - Tubers (best on FLAIR)
Desmoplastic Infantile Ganglioglioma
- DIGs often have large cyst
- Cortically based enhancing tumor nodule
- Enhancing adjacent pia and dura
Desmoplastic Infantile Astrocytoma
- Similar to (but rarer than) DIG
Glioblastoma Multiforme
- Bulky irregular enhancing tumor
- Peritumoral edema, mass effect
- Hemorrhage, central necrosis, cysts
- ↑ glucose metabolism, avid FDG accumulation on PET

Helpful Clues for Rare Diagnoses

Choroid Plexus Carcinoma
- Similar to CPP PLUS
  - Brain invasion
  - Ca++, cysts, bleed
  - Ependymal, subarachnoid space seeding (can be seen with both CPP, CPC)
Atypical Teratoid-Rhabdoid Tumor
- PNET-MB-like PLUS
  - Metastases at diagnosis more common
  - Cysts, hemorrhage more common
  - Cerebellopontine angle cistern location more common
Neurocutaneous Melanosis (Melanoma/Melanocytoma)
- Giant or multiple cutaneous melanocytic nevi PLUS
  - Melanosis: Bright T1 amygdala, cerebellum
  - Melanoma: Melanosis + diffuse leptomeningeal enhancement
Pineoblastoma
- Large heterogeneous pineal region mass
  - Peripheral Ca++
  - Small cysts
  - Inhomogeneous enhancement
- Invades adjacent structures
  - Corpus callosum, thalamus, midbrain, vermis
- Hydrocephalus usual at diagnosis
Brainstem Glioma, Pediatric
- Imaging appearance, prognosis vary with tumor type, location
- Tectal
  - Pilocytic astrocytoma
  - Clinically indolent course (may cause obstructive hydrocephalus)
  - Variable enhancement/Ca++
- Focal tegmental mesencephalic
  - Pilocytic astrocytoma
  - Cyst + nodule
  - Surgery, radiation, or chemotherapy
  - Patients generally do well
- Diffuse pontine glioma
  - Diffusely infiltrating fibrillary astrocytoma
  - Nonenhancing early in course
  - Enhancement with malignant progression
  - Survival generally poor
Medulloepithelioma
- Rare malignant embryonal brain tumor
- Young children (< 5 years)
- Histologic differentiation varies
  - Neuronal, astrocytic, ependymal, melanotic, etc.
- Imaging appearance reflects variable differentiation