Sturge-Weber syndrome (encephalotrigeminal angiomatosis)

Findings

Figure 1 and 2: Enlargement of left frontal sinus; generalized left hemishperic cerebral atrophy with significant white matter involvement; enlargement of ipsilateral choroid plexus of this noncontrast enhanced study; low intensity gyral signal corresponding to gyral calcifications. If CT had been performed in this case, classic "tram-track" calcifications would be seen.
Figure 3: Hyperintense signal within remaining white matter on FLAIR consistent with gliosis.
Figure 4 and Figure 5: Hyperpneumatization of left frontal sinus (Figure 4); generalized left cerebral hemispheric atrophy; skull thickening (Figure 4); enlargement of ipsilateral choroid plexus.


Diagnosis: Sturge-Weber syndrome(encephalotrigeminal angiomatosis)


Sturge Weber syndrome (encephalotrigeminal angiomatosis) is a rare neurocutaneous syndrome in which patient has port wine nevus in V1 (ophthalmic branch) distribution of trigeminal nerve, seizures and occasionally hemiplegia. It is a predominantly sporadic disease. The basic pathophysiology is likely due to faulty development of cortical venous drainage resulting in leptomeningeal angioma formation, venous stasis, vascular congestion, and hypoxia of the affected cortex. Slowly progressive atrophy of the brain underlying the angioma occurs, along with the characteristic cortical calcifications.
On imaging, the classic findings include hemiatrophy with gliosis, ipsilateral choroid plexus hypertrophy due to collateral deep venous flow, and leptomeningeal enhancement (early) or “tram-track” cortical calcifications (late). Enlargement of deep medullary white matter veins can be seen on enhanced MR images and MR venography may show a paucity of cortical veins.
Although the cortical calcifications are best seen on CT imaging, they may also be identified as low-signal intensity cortical signal along cortical gyri. Cortical calcifications are usually progressive, posterior to anterior.
In addition, imaging findings include Dyke-Davidoff-Masson syndrome, characterized by elevated petrous ridge/sphenoid wing, and hemihypertrophy of the skull. There is also hyperpneumatization of the ipsilateral paranasal sinuses, usually frontal sinuses.
Treatment includes longstanding seizure therapy. If seizures are not controlled by medication, surgical resection of the affected lobe may be performed.

Choroid plexus papilloma

Findings

There is a frond-like mass in the trigone of the right lateral ventricle with mostly isointense signal on T1 and T2, demonstrating intense contrast enhancement. There is no local parenchyma invasion. There is severe hydrocephalus.

Differential diagnosis:
- Choroid plexus papilloma
- Choroid plexus carcinoma
- Choroid plexus meningioma
- Villous hypertrophy
- Intraventricular metastasis
- Ependymoma


Diagnosis: Choroid plexus papilloma


Key points

General
- Tumor that arise from the choroid plexus epithelium
- WHO Grade I tumor – benign slow growing tumor
- Four to eight times more common than choroid plexus carcinoma

Epidemiology
- Most common brain tumor in those under 1 year of age
- 75% of cases are in those under 10 years old
- Approximately to 2 to 4% of pediatric brain tumors
- Approximately 0.5% of adult brain tumors

Clinical Presentation
- Signs and symptoms of increased intracranial pressure from CSF overproduction and impaired CSF resorption
- May present with focal neurologic deficit

Treatment
- Surgical resection
- Almost 100% 5 year survival rate for choroid plexus papilloma
- Often require post resection shunting


Radiology

Lobulated, frond, or "cauliflower-like" intraventricular mass
Often arises in the lateral ventricle trigone in children
Often arises in the 4th ventricle and cerebellopontine angle in adults
May have drop metastasis to the spinal canal
Associated with hydrocephalus because of CSF overproduction or obstruction
Only limited local parenchymal invasion (compared to choroid plexus carcinoma)
Often difficult to differentiate from choroid plexus carcinoma

CT
- Iso or hyper dense ventricular mass
- 25% contain punctuate calcification
- Intense enhancement
- May have cysts or hemorrhage

MRI
- T1 Iso or hypo intense
- T2 variable hyper intense, with flow voids
- Intense enhancement

Ventriculitis

Findings

There is a left parieto-occipital ventriculostomy catheter is present entering the left occipital horn. There is diffuse dilation of the lateral ventricles (left greater than right), third ventricle, and fourth ventricle. There is focal, marked enhancement of the occipital horns of the ventricles bilaterally, with debris noted dependently in the lateral ventricles. This debris demonstrates restricted diffusion. There is T2 prolongation in the white matter surrounding the occipital horns bilaterally.

Differential diagnosis:
- Bilateral lateral ventriculitis
- Lymphoma
- Intraventricular hemorrhage
- Ependymal tumor spread (primary or metastatic)
- Prominent ependymal veins


Diagnosis: Ventriculitis


Key points


Ventriculitis is infection of the ependyma lining the ventricles of varying etiologies.
May be caused by rupture of brain abscess into the ventricle, as a complication of meningitis (30% of cases), or as a complication of neurosurgical devices (most common ventriculostomy).
Can be caused by viral, fungal, bacterial, or parasitic organisms. Most common – bacterial (Staphylococcus, Streptococcus, Enterobacter). Viral or fungal – immuno-compromised patients.
High mortality – 40-80%
Treatment – surgical irrigation and drainage, treatment of infectious etiology (antibiotics)

Imaging findings:
- CT: Ventriculomegaly with diffuse enhancement of the ventricular walls. Usually layering debris within the ventricles. Subtle low density surrounding the ventricles (edema).
- MR: Ventriculomegaly with layering debris in the ventricles (hyperintense on T1WI and FLAIR). Debris will demonstrate restricted diffusion on DWI (pus). Bright enhancement of ventricular walls. May have associated findings of choroid plexitis (uncommon).

Idiopathic dural dysplasia

Findings

Figure 1 and Figure 2: Axial and sagittal CT images demonstrate dural ectasia with a capacious thecal sac to the level of the sacrum.
Figure 3 and Figure 4: Sagittal T1 postcontrast and T2-weighted MR images reveal a dilated terminal thecal sac without a tethered cord. Benign subtle scalloping of the posterior margin of the lumbar and sacral vertebral bodies (Figure 4) is best visualized on the T2-weighted images.
Figure 5 and Figure 6: Axial T1 postgadolinium and axial T2-weighted MR images reveal a dilated thecal sac with root sleeve prominence.

Differential diagnosis:
- Idiopathic dural dysplasia
- Neurofibromatosis I
- Marfan syndrome
- Ehlers-Danlos syndrome
- Homocystinuria
- Achondroplasia
- Hurler syndrome (MPS IH)
- Syringomyelia
- Ankylosing spondylitis


Diagnosis: Idiopathic dural dysplasia


This case is an example of an expanded dural sac with posterior vertebral scalloping of the lumbar spine and sacrum. Findings include a capacious thecal sac with smooth scalloping of the posterior aspect of the involved vertebral bodies. Dural dysplasia most often occurs in the lumbar spine but can involve the cervical and thoracic spinal canal as well. The case described herein is mild as there is no resulting kyphoscoliosis or erosion of the pedicles which occurs in more severe cases. Making the diagnosis of dural dysplasia requires that one excludes other causes of the expansion of the canal such as syrinx, tumor or meningeal cyst. The differential diagnosis and etiology of dural dysplasia is extensive and should be distinguished from meningeal cysts. The patient in this case had no known cause for the dural dysplasia and only complained of back pain.


Meningeal cysts
- Type I meningeal cysts: are extradural cysts that do not contain nerve root fibers. Type IA cysts are extradural arachnoid cysts. Occult sacral meningoceles (OIM) are considered type IB meningeal cysts which are also extradural and do not contain nerve root fibers. OIMs present with smooth remodeling and enlargement of the sacral canal with an extradural arachnoid sacral cyst adjacent to the thecal sac.
- Type II meningeal cysts are extradural cysts that contain nerve root fibers. These include Tarlov cysts and spinal nerve root diverticula. Tarlov cysts are cystic dilatation of the sacral root pouches with associated bone erosion which may or may not be symptomatic.
- Type III meningeal cysts are true intradural arachnoid cysts.

Arachnoid cyst with hemorrhage

Findings

Figure 1: CT of the brain without contrast demonstrates a left extra-axial mass occupying the left frontotemporal region, which is relatively isointense to the white matter, measuring approximately 20 Hounsfield units.
Figure 2 : CT of the brain with bone windows demonstrates slight deformity of the calvarium with thinning related to a long-standing process.
Figure 3, 4, 5, 6, 7 and 8: Axial T1, T2, FLAIR and SPGR sequences demonstrate increased signal intensity compatible with subacute hemorrhage into left middle cranial fossa arachnoid cyst with left-to-right midline shift. Note that this is an atypical arachnoid cyst as it does not follow CSF on all sequences.
Figure 9: DWI image from original study obtained several months prior shows characteristic low signal consistent with uncomplicated arachnoid cyst.


Diagnosis: Arachnoid cyst with hemorrhage


Arachnoid cysts are cerebrospinal fluid (CSF) collections contained within a wall of normal arachnoid cells. These structures represent the most common intracranial congenital cystic lesions. They arise during development when the embryonic meninges fail to merge with resultant splitting of the arachnoid membrane. Importantly, they do not openly communicate with the ventricular system or subarachnoid space and typically show delayed opacification upon intrathecal contrast administration.

These lesions account for approximately 1% of all intracranial masses. There is a predilection for males (3:1) and they may be seen in any age group with 75% occurring in the pediatric population. Most cases are incidental findings in adult patients with brain imaging performed for unrelated symptoms. They usually do not enlarge over time however, can expand when CSF pulsations become entrapped in the arachnoid cyst.

When symptoms are present, they are related to the location and size of the lesion. Small cysts are typically asymptomatic whereas large masses present with various clinical features. The most common symptoms and signs include headache, seizures, developmental delay, hydrocephalus, and increased intracranial pressure. Focal neurological signs secondary to direct compression occurring less frequently.

These lesions demonstrate characteristic features on imaging studies as cystic cisternal masses with thin walls containing CSF density (CT) or intensity (MR) fluid. CT findings include a CSF attenuation mass (0 to 20 Hounsfield units) with sulcal effacement, displacement of surrounding structures, and remodeling or erosion of adjacent bone. There is no enhancement of the cystic contents or wall and calcification is rare. Occasionally, hemorrhagic products or proteinaceous fluid may result in higher attenuation and in these cases, MR is often the diagnostic modality of choice. On MR imaging, the extra-axial mass demonstrates signal intensity identical to CSF on all pulse sequences. Thus, it has low signal intensity on T1WI and high signal intensity on T2WI. Additionally, the FLAIR sequence shows a low signal (fluid-attenuated) lesion and diffusion-weighted imaging (DWI) also reveals a low intensity mass demonstrating absence of restricted diffusion.

Most cases do not require treatment and surgery is reserved for cases where symptoms correlate with anatomic location. Treatment options include conventional shunt placement for drainage into the peritoneal cavity or alternatively, cyst fenestration into normal CSF pathways (decompression) through an endoscopic approach or open craniotomy. Patients should be followed with serial scans for progressive cyst enlargement. As this case demonstrates, intracystic hemorrhage is a potential complication. Additional sequelae include secondary infection of the cyst or development of a subdural hematoma/hygroma.

Neurosarcoidosis

Findings

There is demonstrate diffuse, nodular meningeal thickening and enhancement along the convexities, interhemispheric fissures, and skull base. There is associated underlying parenchymal edema within the frontal lobes.

Differential diagnosis
- Granulomatous disease (namely, sarcoid)
- Meningitis
- Metastases
- Meningioma
- Histiocytosis


Diagnosis: Neurosarcoidosis (dural and parenchymal involvement)


Key points

Multisystem inflammatory disease characterized by noncaseating epithelioid-cell granulomas; etiology unknown
CNS involved in 5% clinically (27% autopsy); 10-20 per 100k in North America

Involves
- Dura, leptomeninges, subarachnoid space
- Brain parenchyma to include hypothalamus>brain stem>cerebral hemispheres>cerebellar hemispheres

Solitary or multifocal CNS mass(es)
Approximately 50% have periventricular T2 hyperintense lesions
Perivascular infiltrative involvement Virchow Robin spaces
May induce a small vessel vasculitis

Clinical Presentation:
- Most common symptom - CN deficit(s); most often CN VII; up to 50% asymptomatic
- Age of onset – 3rd-4th decade; 3-5% children; M:F 2:1; African American: Caucasian 10:1
- Pulmonary involvement in >90% of patients (abnormal CXR in association with CNS involvement strong evidence)

Course/Treatment:
- 2/3 have self limited monophasic illness; remainder have chronic remitting-relapsing course
- No known cure


Radiology

CT:
- May show basilar leptomeningeal enhancement
- Osteolytic skull lesions

MR:
- T1 + Contrast
Wide spectrum of enhancement
1/3 have multiple parenchymal lesions
>1/3 have leptomeningeal involvement, nodular and/or diffuse
10% solitary intra-axial mass
5-10% hypothalamus, infundibular thickening
- FLAIR:
Approximately 50% with periventricular T2 hyperintense lesions
Hyperintense vasogenic edema secondary to perivascular infiltrates or small vessel vasculitis
- T2:
Lacune (brainstem, BG)
Hypointense material within subarachnoid space
Hypointense dural lesion(s)
Hydrocephalus

Juvenile angiofibroma

Findings

CT shows a soft tissue mass extending from pterygopalatine fissure into sphenoid sinus with some erosion and expansion of adjacent bony structures. Angiography shows a major hyper vascular tumor supplied by sphenopalatine branch of right internal maxillary artery, without ascending pharyngeal artery supply. Minimal tumor blood supply from sphenopalatine branch of left internal maxillary artery. Super selective embolization of left and right sphenopalatine arteries was performed using Echelon-14 micro catheter and RVA particles (150-250 microns).


Diagnosis: Juvenile angiofibroma


Key points

Epidemiology:
- 1 of every 5,000-6,000 otolaryngological admissions.
- Approximately 0.5% of all head and neck neoplasms.
- Occurs exclusively in adolescent males.

Pathophysiology:
- Highly vascular tumors, locally invasive, non-encapsulated tumors.
- Usually arise at posterior attachment of middle turbinate, near the sphenopalatine foramen.
- Superior growth occurs towards sphenoid sinus, with erosion possible. Invasion into cavernous sinus may also occur.

Clinical:
- Symptoms: epistaxis (45-60%), nasal obstruction (80-90%), headache (25%), facial swelling (10-18%).

Treatment:
- Definitive therapy is usually surgical, with pre-operative embolization to control intraoperative bleeding.
- Hormonal therapy (with testosterone blockers) and radiotherapy have been tried with mixed results.


Radiologic overview

Usually suspected via findings on CT, but angiography used for definitive diagnosis and possible embolization prior to definitive surgery.
Most suggestive finding is a homogenous, nasopharyngeal soft tissue mass causing expansion of the nasal cavity, sometimes with septal deviation, and extending into the pterygopalatine fossa and sphenoid sinus.
Often see anterior bowing of the posterior wall of the ipsilateral maxillary sinus, but rarely with breakthrough into the antrum. Conversely, the tumor often extends superiorly with erosion into the sphenoid sinus, and possibly with extension into the cavernous sinus.
Angiography: 94% of the time, primary feeder system comes from branches of the external carotid system (usually from maxillary artery, but may also include ascending pharyngeal or vidian arteries).