Files

T

Ross 97898e14d2 .

2025-11-02 21:45:44 +00:00

31 KiB

Raw Permalink Blame History

title, docid, authors, breadcrumbs, category, documentVersionId, imageCount, lastUpdated, pageDescription, pageKeywords, pageTitle, enhancedTitle, type, references, breadcrumbs

title

docid

authors

breadcrumbs

KEY FACTS

Terminology
- Rare, benign, well-differentiated, intraventricular ependymal tumor, typically attached to ventricular wall
Imaging
- Intraventricular, inferior 4th ventricle typical (60%)
- Other locations: Lateral > 3rd ventricle > spinal cord
- T2-/FLAIR hyperintense intraventricular mass - Heterogeneity related to cystic changes; blood products or Ca⁺⁺ may be seen in larger lesions
- Variable enhancement, typically none to mild
- T2 and FLAIR are often most sensitive sequences
Top Differential Diagnoses
- Ependymoma
- Central neurocytoma
- Subependymal giant cell astrocytoma
- Choroid plexus papilloma (CPP)
- Hemangioblastoma
- Metastases
Pathology
- WHO grade 1
Clinical Issues
- 40% become symptomatic, often supratentorial - Related to increased intracranial pressure, hydrocephalus
- Present in middle-aged/elderly adults (typically 5th-6th decades)
- Treatment: Conservative management with serial imaging if asymptomatic patient
- Surgical resection is curative in most cases
- Excellent prognosis for supratentorial lesions - Recurrence is extremely rare
Diagnostic Checklist
- If 4th or lateral ventricular hyperintense mass in older man (50-60 years old), think subependymoma

TERMINOLOGY

Synonyms
- Older literature: Subependymal glomerulate astrocytoma, subependymal astrocytoma, subependymal mixed glioma
Definitions
- Rare, benign, well-differentiated, intraventricular ependymal tumor, often attached to ventricular wall

IMAGING

General Features

Best diagnostic clue

- T2-hyperintense, lobular, nonenhancing, intraventricular mass

Location

- Typical: Intraventricular, inferior 4th ventricle (60%)
        - Often protrudes through foramen of Magendie
- Other locations: Lateral > 3rd ventricle > spinal cord (cervical or cervicothoracic)
        - Lateral ventricle: Attached to septum pellucidum or lateral wall
- Rare: Periventricular

Size

- Typically small: 1-2 cm
- May become large: > 5 cm
        - More commonly symptomatic when large

Morphology

- Well-defined, solid, lobular mass
- When large, may see cysts, hemorrhage, Ca⁺⁺

CT Findings

NECT

- Iso- to hypodense intraventricular mass
- Cysts or Ca⁺⁺ may be seen in larger lesions
- Rarely hemorrhage

CECT

- No or mild enhancement typical
- Heterogeneous enhancement may be seen

MR Findings

T1WI

- Intraventricular mass, hypo- or isointense to white matter
- Typically homogeneous solid mass
- Heterogeneity may be seen in larger lesions

T2WI

- Hyperintense intraventricular mass
- Heterogeneity related to cystic changes; blood products or Ca⁺⁺ may be seen in larger lesions
- No edema seen in adjacent brain parenchyma

FLAIR

- Hyperintense intraventricular mass
- No edema seen in adjacent brain parenchyma

T2* GRE

- May see Ca⁺⁺ bloom in larger lesions and 4th ventricle location

T1WI C+

- Variable enhancement, typically none to mild
- Marked enhancement may be seen: More common in 4th than lateral ventricular subependymomas

MRS

- Low metabolites reported
- Lactate peak present in subependymoma
- Elevated Cho peak in central neurocytoma compared with subependymoma

Nuclear Medicine Findings

PET

- Rare reports show exceedingly low rates of glucose metabolism and kinetic constants
        - Hypometabolism indicates low cellular density and slow growth

Imaging Recommendations

Best imaging tool

- MR is most sensitive
- CT may be useful for Ca⁺⁺

Protocol advice

- Multiplanar contrast-enhanced MR, including T2, FLAIR

DIFFERENTIAL DIAGNOSIS

Ependymoma
- Younger patients
- Heterogeneous enhancing mass with edema
- Typically 4th ventricular mass with hydrocephalus
- Often parenchymal when supratentorial
Central Neurocytoma
- Typical "bubbly" appearance, Ca⁺⁺ common
- Lateral ventricle, attached to septum pellucidum
- Moderate to strong enhancement
Subependymal Giant Cell Astrocytoma
- Enhancing mass at foramen of Monro
- Ca⁺⁺ common
- Tuberous sclerosis patients: Subependymal nodules, cortical tubers, white matter lesions
Choroid Plexus Papilloma
- Typically pediatric tumors, lateral ventricle
- In adults, 4th ventricle
- Enhancing papillary mass, hydrocephalus common
Hemangioblastoma
- Cystic mass with enhancing mural nodule
- Typically cerebellar hemispheres, often at pial surface
- Rarely intraventricular
Metastases
- Primary tumor often known
- Often multiple lesions at gray-white junctions
- Typically involve choroid plexus if intraventricular
Cavernous Malformation
- Rarely intraventricular, 2.5-11% of cases
- Ca⁺⁺ and T2 hypointense hemosiderin rim common
- Enhancement variable

PATHOLOGY

General Features

Etiology

- Proposed cells of origin: Subependymal glia, astrocytes of subependymal plate, ependymal cells
        - Development from subependymal glial precursors appears likely

Genetics

- Most are sporadic
- Rare familial cases have been reported

Associated abnormalities

- Contains both astrocytes and ependymal elements
- Occasionally coexists with cellular ependymomas
- Rare: Multiple lesions

Staging, Grading, & Classification
- WHO grade 1
Gross Pathologic & Surgical Features
- Solid, well-delineated, white to grayish avascular mass
- Firmly attached to site of origin - 4th ventricle: Floor typical - Lateral ventricle: Septum pellucidum or lateral wall
- Larger lesions are lobulated, more often Ca⁺⁺; hemorrhage, cyst formation common
- 4th ventricular lesions often protrude out of foramen of Magendie
Microscopic Features
- Highly fibrillar, low cellularity with nuclei clustering
- Microcystic change common in tumors near foramen of Monro
- Ca⁺⁺ is commonly seen in 4th ventricle tumors
- Mitoses are rare or absent, MIB < 1%
- Hemorrhage is rare
- Immunohistochemistry: Strongly GFAP(+)
- Reports of brainstem subependymomas with H3K27M mutations (not more aggressive)
- Electron microscopy: Closely packed cell processes filled with glial intermediate filaments

CLINICAL ISSUES

Presentation

Most common signs/symptoms

- Most asymptomatic
- 40% become symptomatic, often supratentorial
        - Related to increased intracranial pressure, hydrocephalus
                  - Headache, gait ataxia, visual disturbance, cranial neuropathy, nystagmus, vertigo, nausea, vomiting
- If spinal location, motor or sensory deficits

Demographics

Age

- Middle-aged/elderly adult (typically 5th-6th decades)
        - Asymptomatic patients: Mean age = 60 years
        - Symptomatic patients: Mean age = 40 years
- Rare in children

Sex
```
- Male predominance, M:F = 2.3:1
```

Epidemiology

- Reported in 0.5-1% of autopsies
- Account for 0.7% of intracranial neoplasms
- Represent ~ 8% of ependymal tumors

Natural History & Prognosis
- Excellent prognosis for supratentorial lesions
- Recurrence is extremely rare
- Complications include hydrocephalus and rarely hemorrhage
- Rare, benign, slow-growing tumors often found incidentally at imaging or autopsy
Treatment
- Surgical resection is curative in most cases - Lateral ventricle lesions: Complete resection - 4th ventricle lesions: Subtotal resection more common
- Perioperative mortality low but increased by attachment of tumor to adjacent structures
- If hydrocephalus, CSF diversion may be required
- Adjuvant radiation therapy is controversial
- Conservative management with serial imaging if asymptomatic

DIAGNOSTIC CHECKLIST

Consider
- Other intraventricular tumors tend to enhance more prominently
- May be indistinguishable from ependymoma or central neurocytoma
- Differential diagnosis varies with age - Adults: Central neurocytoma, choroid plexus papilloma, metastases, hemangioblastoma - Children: Ependymoma, choroid plexus papilloma, subependymal giant cell astrocytoma
Image Interpretation Pearls
- If 4th or lateral ventricular hyperintense mass in older man, think subependymoma
- T2 and FLAIR are often most sensitive

411ddf02-7d9e-49d8-ad4f-5ce7fc41fc3f

References

Selected References

Images

Selected Images

Sagittal T2 MR shows a solid, hyperintense mass along the inferior 4th ventricle in a 64-year-old man with headaches. A subependymoma was found at resection. These 4th ventricular tumors are often asymptomatic. T2 and FLAIR are typically the most sensitive sequences to identify this WHO grade 1 tumor.

Sagittal graphic shows a solid, well-circumscribed mass arising from the floor of the 4th ventricle with mild mass effect . Note the lack of hydrocephalus and edema in the adjacent brain, typical of a subependymoma.

Axial T2 MR shows a hyperintense mass along the inferior 4th ventricle at the level of the medulla. This case shows classic imaging of a subependymoma.

Axial FLAIR MR in a 62-year-old man with a headache shows a hyperintense mass filling the 4th ventricle . Note the lack of edema in the surrounding brain. Subependymomas are most commonly found in the inferior 4th ventricle (50-60%). The lateral ventricle is the next most common location (30-40%). Surgical resection is typically curative.

Axial T1 C+ MR shows an enhancing mass in the 4th ventricular outflow tract . The moderate enhancement is uncommon. Subependymomas classically have no or minimal enhancement. They can protrude through the foramen of Magendie. In this case, tumor is also present anterior to the cerebellar hemisphere through the foramen of Luschka.

Axial T2 MR shows a heterogeneous right lateral ventricle mass in a 58-year-old man. Subependymoma was found at resection. Imaging mimics a cavernous malformation.

Coronal graphic shows a solid, well-circumscribed, intraventricular mass attached to the septum pellucidum with neither mass effect nor hydrocephalus. Subependymomas are typically asymptomatic, but they may cause hydrocephalus and increased intracranial pressure.

Coronal T1 C+ MR in a 35-year-old man shows a lateral ventricle mass with central enhancement and mild mass effect on the septum pellucidum. Note the lack of associated hydrocephalus, typical of a subependymoma.

Axial FLAIR MR shows a hyperintense lateral ventricle mass at the level of the septum pellucidum. Subependymomas in the lateral ventricle are typically attached to the septum pellucidum or lateral wall.

Sagittal T1 C+ MR shows a large enhancing mass filling the 4th ventricle. Cysts, blood, and Ca⁺⁺ may be seen in larger subependymomas. Imaging may mimic other ventricular masses, including choroid plexus papilloma, ependymoma, and hemangioblastoma.

Additional Images

Axial T1 C+ MR in an older man with headaches shows a well-circumscribed, enhancing mass attached to the septum pellucidum; it proved to be a subependymoma. No enhancement or mild enhancement is typical.

Axial NECT shows a calcified 4th ventricular mass in this 52-year-old woman. Calcification is more commonly seen in 4th ventricular subependymomas than in others.

Sagittal T1WI C+ MR in a 60-year-old man shows a classic, nonenhancing 4th ventricular subependymoma . The origin in the 4th ventricular floor is typical. The mass may be best seen on T2WI &/or FLAIR.

Axial T2WI MR shows a circumscribed, hyperintense, subependymal mass. No enhancement was present on contrast images. This 56-year-old man with headaches was diagnosed with subependymoma in an atypical periventricular location.

Sagittal T2WI MR shows a solid, hyperintense mass along the inferior 4th ventricle in a 43-year-old man with headaches and trigeminal neuralgia. Subependymoma was found at resection. These 4th ventricular tumors are often asymptomatic. T2 and FLAIR are typically the most sensitive sequences for this tumor.

Axial FLAIR MR shows a hyperintense lateral ventricle mass at the level of the septum pellucidum. When in the lateral ventricle, subependymomas are typically attached to the septum pellucidum or lateral wall.

Axial T1 C+ MR shows a markedly enhancing 4th ventricular mass . Differential considerations include ependymoma and choroid plexus papilloma. Subependymoma was diagnosed at resection.

Sagittal T2WI MR shows a heterogeneous mass filling the 4th ventricle with inferior extension. Enhancement was present on contrast images of this WHO grade I subependymoma. Cysts, blood, and Ca⁺⁺ may be seen in larger lesions. Imaging mimics ependymoma and hemangioblastoma.

Sagittal FLAIR MR shows a solid, hyperintense mass along the inferior 4th ventricle in a 64-year-old man with headaches. Subependymoma was found at resection. These 4th ventricular tumors are often asymptomatic. T2 and FLAIR are typically the most sensitive sequences to identify this WHO grade I tumor.

31 KiB Raw Permalink Blame History

KEY FACTS

Terminology

Imaging

Top Differential Diagnoses

Pathology

Clinical Issues

Diagnostic Checklist

TERMINOLOGY

Synonyms

Definitions

IMAGING

General Features

Best diagnostic clue

Location

Size

Morphology

CT Findings

NECT

CECT

MR Findings

T1WI

T2WI

FLAIR

T2* GRE

T1WI C+

MRS

Nuclear Medicine Findings

PET

Imaging Recommendations

Best imaging tool

Protocol advice

DIFFERENTIAL DIAGNOSIS

Ependymoma

Central Neurocytoma

Metastases

PATHOLOGY

General Features

Etiology

Genetics

Associated abnormalities

Staging, Grading, & Classification

Gross Pathologic & Surgical Features

Microscopic Features

CLINICAL ISSUES

Presentation

Most common signs/symptoms

Demographics

Age

Sex

Epidemiology

Natural History & Prognosis

Treatment

DIAGNOSTIC CHECKLIST

Consider

Image Interpretation Pearls

References

Selected References

Images

Selected Images

Additional Images

31 KiB

Raw Permalink Blame History