Solitary Hyperdense Parenchymal Lesion

Anne G. Osborn, MD, FACR

DIFFERENTIAL DIAGNOSIS

Common

Cerebral Contusion
Hypertensive Intracranial Hemorrhage
Cerebral Amyloid Disease
Glioblastoma Multiforme
Metastasis, Parenchymal
Thrombosis, Dural Sinus
Thrombosis, Cortical Venous

Less Common

Cavernous Malformation
Developmental Venous Anomaly
Arteriovenous Malformation
Medulloblastoma (PNET-MB)
Ependymoma, Supratentorial
Melanoma
Ganglioglioma
Lymphoma, Primary CNS
Germinoma
Anaplastic Oligodendroglioma

Rare but Important

Drug Abuse
Tuberculoma
Neurosarcoid
Leukemia
Tuberous Sclerosis Complex
Meningioangiomatosis

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Hyperdense parenchymal lesions
- ↑ Attenuation compared to normal brain
Caused by
- Clotted blood (most common)
- Nonhemorrhagic hypercellular (electron dense) mass (less common)
- Calcification (excluded here)
History essential
- Age
- Trauma, hypertension, drug abuse, dementia, known extracranial primary neoplasm
- Sudden onset vs. subacute/chronic

Helpful Clues for Common Diagnoses

Cerebral Contusion
- Trauma
- Location important
  - Cortex, subcortical white matter
  - Anterior inferior frontal, temporal lobes most common
  - Multiple > > solitary lesion
- Evolves over time; 24-48 hours existing lesion may enlarge, become more hemorrhagic
Hypertensive Intracranial Hemorrhage
- Older hypertensive patient
- Location important
  - Deep > superficial lesion
  - Nearly 2/3 striatocapsular
  - Thalamus 15-25%
- Look for multifocal “microbleeds”
  - 1-5%
  - Best seen on T2* MR
Cerebral Amyloid Disease
- Causes 15-20% of all “spontaneous” intracranial hemorrhages (ICHs) in normotensive elderly patients
- Classic = lobar hemorrhage (vs. basal ganglia in hypertension)
- Look for “microbleeds” (do T2* MR)
  - Cortical/subcortical vs. basal ganglia, cerebellum (chronic hypertension)
Glioblastoma Multiforme
- Necrosis, hemorrhage common
Metastasis, Parenchymal
- Can be hemorrhagic or nonhemorrhagic
- Hypercellular, electron dense nonhemorrhagic metastases
Thrombosis, Dural Sinus
- Multifocal > solitary hemorrhage
- Parenchymal clot(s) adjacent to dural sinus (transverse sinus > superior sagittal sinus)
Thrombosis, Cortical Venous
- Multifocal > solitary hemorrhage
- Can occur with or without dural sinus occlusion

Helpful Clues for Less Common Diagnoses

Cavernous Malformation
- Variable presentation
- Acute hemorrhage
  - Common cause of spontaneous ICH in children, young adults
- Epilepsy
  - Hyperdense calcified or noncalcified parenchymal mass
Developmental Venous Anomaly
- Hemorrhage rare unless mixed with cavernous malformation
- Blood in transcortical draining vein slightly hyperdense to brain
Arteriovenous Malformation
- Common cause of spontaneous ICH in children, young adults
- Rupture of intranidal aneurysm, stenosis/occlusion of draining veins
Medulloblastoma (PNET-MB)
- Electron dense tumor with high nuclear: cytoplasm ratio
- Midline hyperdense posterior fossa mass in child? Suspect PNET-MB
- Lateral (cerebellar) mass in older child/young adult? Suspect desmoplastic variant of medulloblastoma
Ependymoma, Supratentorial
- Most ependymomas are intraventricular, but up to 40% are supratentorial, parenchymal > intraventricular
- Large hyperdense calcified solid/cystic hemispheric tumor in young child? Think ependymoma!
Melanoma
- Metastatic > primary CNS melanotic lesion
- Melanin or hemorrhage → ↑ density
Ganglioglioma
- Child/young adult with epilepsy
- Most are partially cystic, contain Ca++
Lymphoma, Primary CNS
- Corpus callosum, basal ganglia
- Hemorrhage rare unless HIV/AIDS
Germinoma
- Pineal > infundibulum > basal ganglia
- Densely cellular tumor but may also hemorrhage
- Hyperdense basal ganglia mass in child/young adult? Think germinoma!
Anaplastic Oligodendroglioma
- Mixed density common
- May Ca++, hemorrhage

Helpful Clues for Rare Diagnoses

Drug Abuse
- Striatocapsular hemorrhage in young/middle-aged adult? Consider drug abuse
Tuberculoma
- Granuloma mildly hyperdense
- Can mimic intra- or extra-axial neoplasm
Neurosarcoid
- Multifocal > solitary
- Extra-axial > parenchymal mass(es)
Leukemia
- Extra-axial > intra-axial lesion
- Hyperdense parenchymal lesion can be hemorrhagic complication (more common) or chloroma (less common)
Tuberous Sclerosis Complex
- Cortical, subcortical tubers can be hyperdense &/or calcified
- Multifocal > solitary
- Solitary large, “lobar-type” hyperdense tuber ± Ca++ can mimic neoplasm
Meningioangiomatosis
- Cortical-based, gyriform hyperdensity
- May be densely calcified
- Can mimic neoplasm!

Image Gallery

Axial NECT shows a left frontal hyperdensity with surrounding hypodensity, typical of cortical contusion. Note effaced frontal sulci from focal mass effect.

Axial NECT demonstrates the high density mass

with surrounding low density edema

in the most common location for hypertensive hemorrhage. Note compression of the right lateral ventricle by the mass.

(Left) Axial NECT shows focal lobar hematoma

in a 68 yo normotensive, mildly demented patient with sudden onset of right-sided weakness. T2* MR scan showed multifocal peripheral “black dots” characteristic of amyloid angiopathy. (Right) Axial NECT shows inhomogeneously hyperdense hematoma