Saturday 29 June 2013

Plexiform Neurofibroma MRI

A 20 y o female.
MRI Pelvis
Sequences: Cor STIR, T1WI. Axial STIR and T2WI.
This MRI study reveals T2 hyper intense multi lobulated / conglomerate masses along right sided exiting sacral nerve roots in pre sacral region, extending along sacral nerve at greater sciatic notch deep to Gluteal muscles.

Imaging wise possible diagnosis: Plexiform Neurofibroma.

Excisional biopsy done.

Histo pathology Report

Gross appearance : The specimen consist of multiple fusiform, globular yellowish white nodular tissue together measuring 6x4cm. The nodules appear encapsulated with overall rubbery consistency. The cut section shows dull yellowish white appearance. Representative sections are submitted for processing. Codes A and B.

Microscopy : Sections A and B both show benign encapsulated neoplasm of peripheral nerve sheath origin, comprising interlacing fascicles. whorls and bundles of slender - spindle shaped cells having wavy elongated nuclei and scanty eosinophilic cytoplasm. The interstitial stroma shows variable myxoid change along with fatty tissue, congested blood vessels and residual mononuclear inflammatory infiltrates. There is no evidence of malignancy.

Final diagnosis : Neural Plexiform lesion_ Plexiform Neurofibroma.

Thursday 27 June 2013

Sellar Suprasellar mass DDs

A 49 yo male.
Non contrast CT, MRI Brain with contrast
Non contrast CT
Non contrast T1
Non contrast T1

Post contrast T1 MRI


This MRI study shows:
A well-demarcated sellar supra sellar solid mass with right para sellar component.
Expansion of right half of Sella. No direct Sphenoid sinus extension.
Size of the mass 46mm width, 30mm AP, and height 48mm.
Mass is multi lobulated, Cysts around the lesion can be attributed to areas of cystic degeneration or an associated adjacent meningeal cysts. Signals are homogeneously isointense on T1w and T2w images. Homogeneous enhancement on post contrast T1.
A tissue resembling Pituitary is seen at the floor of left half of hypophyseal fossa on Sagittal T1 and Post contrast T1 sections.
Extension and mass effect _ Prepontine cistern extension causing Basilar compression and encasement. Mid brain and Pons compressed. Right para sellar component causing encasement of right ICA. Optic Chiasma, Optic nerve significantly compressed.
Low signal intensity hemosiderin staining along sub arachnoid space on T2* GRE attributed to superficial siderosis.
Moderate communicating hydrocephalus.

Imaging wise possible DDs: Meningioma more likely than Macro adenoma as pituitary seen separately.

Operated with right sub frontal approach.

Histopathology Report

Gross appearance : The Specimen consist of friable pieces of dull grey tan tissue. The entire tissue submitted for processing. 
Microscopy : Section shows fragmented bits of hyper cellular neoplasm of probable meningothelial cell origin. Tumour consist largely of cohesive sheets of intermediate sized round to oval cells having modestly hyper chromatic nuclei with delicate - irregularly condensed chromatin and scantly eosinophillic to clear cytoplasm having indistinct cytoplasmic membranes. Many neoplastic cells display nucleoli. Overall the tissue reveals 1 to 2 mitosis per 10 HPF. The interstitial stroma shows numerous congested blood vessels. The adjacent stroma shows foci of hyalinised blood vessels. There is no e/o vascular space invasion. Couple of foci show areas of tumor hemorrhage with focal coagulative necrosis. There is no e/o brain invasion. 

Final Diagnosis : Atypical Meningioma Grade II of III (as per  WHO Classification)

Fourth ventricular mass MRI

A 7 y o female.

Sequences planned are FSE T1W, FSE T2W, FLAIR, T2w *GRE and DW images.
Post contrast T1w.
Axial T2w localizer taken and Single voxel MR Spectroscopy performed. The voxel of size 2x2cm placed over the lesion. Water suppression obtained was 99% with optimum spectral waveform obtained at short as well as long TE.
Non contrast CT.

Description of findings:

An ~50x40mm solid hyper dense well defined mass in the region of fourth ventricle on non contrast CT. Lesion is iso intense on T2 and FLAIR. High signal on Dw images. Avid enhancement on post contrast T1 marked at periphery.
Significant mass effect _ moderate obstructive hydrocephalus with mild peri ventricular ooze of Csf. Brain stem compressed.

MRI SPECTROSCOPY performed over lesion.
On short TE of 35ms and TR of 1500ms.
From right to left.
At 2.01ppm - short peak of NAA. NAA is reduced.
At 3.03ppm - short peak of Creatinine.
At 3.2ppm - sharp and long peak of Choline. High choline.
A peak of lactate at 1.4.
NAA/ Creatinine ratio is 1:1
Choline/ Creatinine ratio is 2:1

Imaging possible diagnosis: Medulloblastoma. 

Operated, posterior fossa craniotomy done.

Histopathology report 

Gross specimen : specimen consist of multiple irregular soft to friable pieces of dull – gray tan tissue. Representative sections submitted for processing. Codes : A and B.

Microscopy : sections A and B show a cellular neoplasm composed of medium sized cells with indistinct outlines and round oval or angular hyperchromatic nuclei varying in size. The larger nuclei show clumped chromatin. A fine fibrillary background is discerned between the cells at many places. Peri vascular arrangement of tumor cells with fibrillary processes arising from the cells and extending towards the blood vessels in the center are seen. The tumor is vascular and shows areas of hemorrhage.

Histopathological Diagnosis: Medulloblastoma. 

Similar cases of Medulloblastoma. 
Case 1 : Medulloblastoma MR Spectroscopy 
Case 2 : Medullobastoma lateral origin


Syn: MB, Posterior fossa PNET, PNET – MB,
A highly cellular embryonal cell tumor.
Age group : common in children, ~75% diagnosed by 10 years.
3 times more common in males.

Intraventricular – 4th ventricular roof is a typical and most common location. A most common posterior fossa tumour in children.
Lateral origin – Cerebellar hemisphere is an atypical location common in older children and adults.

Size vary, average size ranges between 3- 5cm at the time of presentation.
On Non contrast CT, solid 4th ventricle mass, hyperdense, calcifcaiton seen in ~20% cases, small intra tumoural cysts, necrosis in ~50% cases.
On MR signal on T1 iso - hypo intense to cortical grey matter on T1 , iso – hyperintense on T2w and FLAIR. High signal on diffusion attributed to its dense, highly cellular nature.
An associated Obstructive hydrocephalus is common seen in ~ 95% cases.
Usually mild to moderate and homogenous enhancement, may show patchy heterogeneous enhancement due to areas of necrosis.

On MR Spectroscopy, NAA reduced or absent as it’s a non neuronal tumour, raised choline.

Sunday 23 June 2013

Posterior Fossa Arachnoid cyst MRI

MRI Brain
Seq planned are Axial FLAIR, T2, Sag T2, Axial Diffusion. 

This MRI study of Brain shows:
Wide posterior fossa with scalloping.
Posterior fossa cyst iso intense to Csf. No restricted diffusion on Dw images. Cyst non communicating with fourth ventricle. Fourth ventricle normal sized.
An associated hypoplastic left cerebellar hemisphere.

An associated Dysgenesis of posterior portion of Corpus callosum with Colpocephaly.
Cerebellar tonsils protruding down across foramen magnum_ Arnold chiari type i malformation with an associated cervical cord syrinx.

Imaging wise diagnosis : Posterior fossa Arachnoid cyst.

DDs ruled out are Dandy walker and other cerebellar malformation as Cyst non communicating with fourth ventricle. Epidermoid Cyst ruled out as no restricted diffusion on Dw images.

Operated and excisional biopsy done.

Histopathology Report

Gross appearance : The specimen consist of thin pearly white soft membranous cystic tissue. The entire tissue submitted for processing.
Microscopy : Sections shows thin undulating delicate fibro collagenous cyst wall lined by meningothelial cells, at places seen to form focal aggregates. There is no e/o cytotological atypia.

Final Diagnosis : Arachnoid cyst.

Tuesday 4 June 2013

Intraventricular Arachnoid cyst MRI

A 30 years old female with history of progressive headache, giddiness and vomiting.

Here is Non contrast CT Brain, MRI Brain with axial T2, T2*GRE, Diffusion and post contrast T1w images. 


Non contrast CT Brain : Marked dilatation of fourth ventricle iso dense to Csf. Mild non communicating hydrocephalus. Dilated outlet foramen of fourth ventricle. 
Diffuse cerebral edema.

MRI Brain : Fourth ventricular lesion is iso intense to Csf, non enhancing on post contrast T1.l
No restricted diffusion on Dw images.
No low signal intensity hemosiderin staining or calcification on GRE.

Posterior fossa craniotomy done.
Intra operative finding is Intra ventricular Arachnoid cyst. 

Van Der Knaap Leukoencephalopathy MRI

A 3 year old female, larger head relative to rest of the body.
Product of non consanguineous marriage. 
Clinical and neurological examination shows delayed milestones, walking imbalance. 
History of similar illness in elder sister. 
MRI study of brain shows:
Diffuses cerebral white matter involvement. Early involvement of sub cortical white matter. Sub cortical white matter cysts iso intense to Csf representing white matter paucity in temporal regions.
Basal ganglia and internal capsules spared.
Cerebral cortical atrophy.
Minimal involvement of Cerebellar white matter.

On MRS reduced NAA and slightly raised Choline peak.

Imaging findings of bilateral diffuse white matter disease, involvement sub cortical white matter with cysts, sparing basal ganglia and internal capsules with Macrocephaly clinically goes in favour of Van der Knaap disease.

Vander Knaap Leukoencephalopathy

Abbreviations and Syn: 
1. MLC: Megaloencephalic leukoencephalopathy with subcortical cysts, formerly known as Vacuolating megaloencephalic leukoencephalopathy with benign, slowly progressive course.
2. VWM: Leukoencephalopathy with Vanishing white matter (WM), Alternatively called CACH (Childhood ataxia central hypomyelination)
3. WML: White matter disease with lactate.
4. H-ABC: Hypomyelination with atrophy of the basal ganglia (BG) and cerebellum.

Imaging findings and diagnostic clues: 
Swollen WM involvement is diffuse, includes subcortical U-fibers.
Subcortical cysts makred in anterior temporal and fronto parietal white matter.
Spares internal capsules, BG, thalami
Cerebellar involvement subtle.
WM replaced by CSF signal, involvement is diffuse WM, includes subcortical U-fibers.
BG and thalami not involved.
Trackt-like ventral trigeminothalamic and central tegmental tract demyelination in brain stem
Cerebellar WM involved.
Diffuse periventricular, deep cerebral WM.
Spared subcortical U-fibers.
Posterior corpus callosum and posterior limb of internal capsule involved.
In Brainstem cerebral Peduncles, pyramidal tracts, medial lemniscus, intraparenchymal trajectories of trigeminal nerves, anterior spinocerebellar tracts involved.
Cerebellar WM involved later, but then notably abnormal.
Spinal involvement an important feature. In spine dorsal columns and lateral corticospinal tracts involvement is typical.
Atrophy of BG and cerebellum.
Diffuse hypomyelination of cerebral WM.
Subcortical U-fibers involved.

In all varieties involved WM show reduced attenuation. No contrast-enhancement.
In all involved WM show decreased signal on Tl WI and increased signal on T2WI
In MLC: Anterotemporal and frontoparietal subcortical cysts approximate CSF signal.
In VWM: Involved WM approximates CSF signal.
DWI: both MLC and WML on DTI shows decreased anisotropy and increased ADC values
No contrast-enhancement on post contrast study.
On MR spectroscopy in MLC all metabolites decreased in cystic regions with reduced NAA in
WM, +/- lactate. In VWM: All metabolites of affected WM disappear as the WM disappears; +/-lactate , glucose signals. In WML: Positive lactate peak; normal to mildly increased Cho,
reduced NAA, increased myo-inositol. In H-ABC: Increased Myo-inositol and creatine (gliosis) in WM;reduced frontal NAA, but otherwise NAA relatively normal

Differential Diagnosis: 

DDs of macrocephaly with   diffuse leukoencephalopathy is limited includes Canavan disease, Alexander disease, infantile-onset GM2 gangliosidosis and laminin alpha-2 (merosin) deficiency.

Laminin alpha 2 deficiency: The white matter disease in laminin alpha-2 deficiency most closely resembles that observed in MLC; however, the typical subcortical cysts of van der Knaap are lacking. Individuals with laminin alpha-2 deficiency have prominent weakness and hypotonia, not seen with MLC - van der Knaap. Molecular genetic testing will be confirmative.
Canavan disease: Typically shows involvement of the thalamus and globus pallidus with relative sparing of Putamen and caudate nucleus. The globus pallidus and thalamus are not involved in MLC. The white matter may be cystic in Canavan disease, but the typical subcortical cysts seen in MLC are lacking. Confrmation of Canavan disease possible by demonstration of very high concentration of NAA in the urine and/or molecular genetic testing of ASPA.
Alexander disease: Megalencephaly and leukoencephalopathy with frontal predominance on MRI is typical with contrast enhancement of particular brain structures  not a feature of MLC. Cystic degeneration may occur in Alexander disease, but the location of the cysts is frontal. Alexander disease can be confirmed by molecular genetic testing of GFAP.
Infantile GM2 gangliosidosis: MRI characterized by prominent involvement of the basal ganglia and thalami in addition to the white matter abnormalities. Demonstration of assaying hexosaminidase A and B in serum, leukocytes, or cultured skin fibroblast will be confirmtative.

General Features: None have systemic or other organ involvement

MLC: Autosomal recessive; gene localized on chr22q(tel); 26 different mutations of MLCI gene. Encodes putative CNS membrane transporter
VWM: Recessive inheritance; gene on 3q27,mutations in genes that encode eIF2B subunits: EIF2Bl-S.
WML: Autosomal recessive inheritance likely.
H-ABC: Unknown, 7 cases in literature (no sibling pairs, so inheritance unknown)

All are inborn genetic errors

All are extremely rare
MLC and VWM rare, but carrier rate is high in some communities with high levels consanguinity.
Common MLC mutations in specific Indian community (Agarwal), Libyan Jewish, and Turkish populations due to founder effect.
Common VWM mutations in certain regions of Netherlands.

MLC: Macrocephaly before the age of 1year
VWM: Young children (slower progression of older onset of symptoms)
WML: Older children, adolescents, young adults
H-ABC: 1-20 years.

Clinical Presentation
Most common signs/symptoms
MLC: Macrocephaly. Delayed onset slow motor deterioration. Slower cognitive decline.Cerebellar ataxia and pyramidal tract involvement, motor deterioration, seizures.
VWM: Episodes of major deterioration and coma following infection or minor head trauma. Relatively preserved cognition.
WML: Slowly progressive pyramidal, cerebellar and dorsal column dysfunction. Spasticity and ataxia. preserved cognitionr
H-ABC: Progressive extrapyramidal symptom like ataxia.


Establish the extent of disease in an individual diagnosed with megalencephalic leukoencephalopathy with subcortical cysts (MLC) by
• Neurologic examination
• Brain MRI
• Physical therapy/occupational therapy assessment
• Assessment of cognitive dysfunction (neuropsychological testing)

Supportive therapy includes the following:
• Antiepileptic drugs (AED) if epileptic seizures are present
• Physical therapy to improve motor function
• Special education
• Speech therapy as needed

Prevention of Secondary Complications from minor head trauma.
Evaluation of Relatives at Risk with Genetic Counseling.

Reference : Diagnostic Imaging Osborn.

Similar case of Van Der Knaap Leukoencephalopathy Click here