Ependymal Enhancement

Bronwyn E. Hamilton, MD

DIFFERENTIAL DIAGNOSIS

Common

Less Common

Rare but Important

Subependymal Venous Congestion
- Sturge-Weber Syndrome
- Thrombosis, Deep Cerebral Venous
- Arteriovenous Malformation or Dural A-V Fistula
Vasculitis
Neurosarcoid
Langerhans Cell Histiocytosis

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Pre-operative neuraxis MR (imaging) recommended in patients suspected of having CSF seeding of tumor

Helpful Clues for Common Diagnoses

Normal Variant
- Subependymal veins enhance normally & may be mistaken for pathology
Developmental Venous Anomaly
- Enhancing “Medusa head” (dilated medullary white matter veins)
- May have enlarged subependymal veins
- Almost always unilateral, focal lesion
- Angle of ventricle common location
Multiple Sclerosis
- Common locations: Subependymal, periventricular, posterior fossa
- Ovoid or round enhancing lesion with no significant mass effect
- “Horseshoe” (incomplete ring enhancement) characteristic of demyelination
- Tumefactive MS may mimic neoplasm, and enhancement may extend to ependyma

Helpful Clues for Less Common Diagnoses

Ventriculitis
- Ventriculomegaly with fluid-debris level & enhancement characteristic
- Associated DWI restriction typical
- May complicate meningitis, abscess, or shunt
Opportunistic Infection, AIDS
- CMV commonly causes ventriculitis
- TB may cause ventriculitis
- Toxoplasmosis may extend to ependyma & mimic lymphoma
Neoplasm with CSF Seeding
- Many parenchymal tumors result in ependymal spread as they abut ventricular surfaces
- Ependymal spread most common in childhood tumors: Medulloblastoma > ependymoma, pineal & choroid plexus tumors
- Malignant gliomas in adults (GBM, anaplastic astrocytoma/oligodendroglioma) commonly spread along ependyma
- Metastases from extracranial primary: Breast & lung most common
Lymphoma, Primary CNS
- Enhancing lesion(s) within basal ganglia, periventricular WM
- Frequently abut, extend along ependymal surfaces
- Often involves, crosses corpus callosum
Tuberculosis
- Typically basal meningitis, may be complicated by ventriculitis
- Dural & parenchymal disease common

Helpful Clues for Rare Diagnoses

Sturge-Weber Syndrome
- May cause subependymal venous congestion
- Cortical Ca++, atrophy, & enlarged ipsilateral choroid plexus
- Usually a sporadic congenital malformation in which fetal cortical veins fail to develop normally
Thrombosis, Deep Cerebral Venous
- Hyperdense internal cerebral veins on NECT
- Usually affects bilateral internal cerebral veins and variably involves vein of Galen & straight sinus
- Deep gray nuclei, internal capsule, medullary WM typically affected
- Venous stasis in deep WM (medullary) veins seen as linear enhancing foci radiating outwards from ventricles
- May cause subependymal venous congestion
Arteriovenous Malformation or Dural A-V Fistula
- AVM: Vascular malformation with arteriovenous shunting
  - Tightly packed mass of enlarged, enhancing vascular channels
  - May cause subependymal venous congestion
- DAVF: Network of tiny vessels in wall of thrombosed dural venous sinus
  - Transverse sinus > cavernous sinus
  - May thrombose, resulting in venous infarct
  - May cause subependymal venous congestion
Vasculitis
- Linear enhancement along course of penetrating vessels
- Enhancement often extends to ventricular margins
- Extensive T2 hyperintense white matter common
Neurosarcoid
- Leptomeningeal & dural enhancing masses
- May occur intraventricularly or along ependyma
Langerhans Cell Histiocytosis
- Rare subependymal involvement by perivascular space infiltration
- May affect choroid plexus

Alternative Differential Approaches

Neoplasm with CSF seeding: Medulloblastoma, ependymoma, germinoma, GBM, metastases, lymphoma, anaplastic astrocytoma, anaplastic oligodendroglioma, choroid plexus tumors, pineoblastoma, leukemia
Ependymal enhancement in a child: Medulloblastoma, ependymoma, choroid plexus or pineal tumor, leukemia
Ependymal enhancement in an adult: High-grade gliomas, metastases, lymphoma, multiple sclerosis
All ages: Normal variant, developmental venous anomaly, ventriculitis