Fourth ventricular mass MRI

A 7 y o female.

MRI BRAIN WITH MR SPECTROSCOPY
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

MEDULLOBLASTOMA

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.

Location:
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.

Medulloblastoma (Lateral origin)

A 30 yo female with giddiness.

Findings:
A hyper dense right Cp angle mass with fluid – fluid levels on Non contrast CT.
On  MRI, lesion is iso intense to cortical grey matter on T1 as well as T2 images.
Restricted diffusion on diffusion weighted images.
Faint heterogeneous enhancement on post contrast T1.
Multiple fluid – fluid levels with low signal intensity hemosiderin staining in dependent portions on T2*GRE implies to intra lesional bleed, a faint focus of T1 bright signal in dependent portion of mass attributed to meth Hb – a sub acute stage blood degradation product.
A rim of perilesional edema in adjacent right cerebellar hemisphere.
It is difficult to comment whether lesion is extra axial or intra axial as cerebellum is displaced by mass but there is no clear demarcation between the mass and cerebellum even on post contrast T1.
Single voxel MR Spectroscopy shows significantly reduced NAA at 2ppm, high choline at 3.2ppm  and a lactate peak at 1.3ppm.
Mass effect significant, medulla and Pons compressed. Obstructive hydrocephalus due to fourth ventricle compression evident by mild dilatation of temporal horns of lateral ventricle.

Imagingwise Possible DDs: Medulloblastoma, Meningioma.
Acoustic Schwannoma unlikely as there is no intra canalicular extension or widening of IAC.

Histopathology report : Medulloblastoma – Classic Desmoplastic variant, WHO Grade IV with lateral cerebellar origin – atypical for location. 


Medullobastoma
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.


Location:
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.


Other cases of Medulloblastoma with typical location and drop metastasis.

Medulloblastoma MR Spectroscopy

An 14 yo male with persistent headache, nausea and vomiting.

Description:
A well circumscribed ovoid intra ventricular space occupying mass completely occupying and expanding fourth ventricle, leading to obstructive hydrocephalus.
Signals of mass corresponds to dense soft tissue, isointense to cortical grey matter on T1 and Flair, slightly hyperintense on T2.
No cystic component or marked areas of necrosis.
Restricted diffusion on Dw images.
Lobulated mild enhancement on post contrast T1.
On single voxel MR Spectroscopy at short TE of 35 ms, no peak of NAA at 2.01ppm, no peak of creatine at 3.02 with peak of raised choline at 3.2ppm.

Imaging and MR Spectrocsopy findings are very typical for a Medulloblastoma.

Diagnostic clues:
Dense 4th ventricular mass,
Hyper dense (~90%) on CT with spotty calcification (~20%) ,
Nearly isointense to cortical grey matter on MRI with restricted diffusion on Dw images.
Markedly reduced or no peak of NAA with high choline on MRS implies to non neuronal / Non Glial neoplasm.
May see drop metastasis.
Age group ~75% < 10 years; M > F.

Similar posts:
Medulloblastoma with drop metastasis
Lateral origin medullobastoma

MEDULLOBLASTOMA

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.

Location:
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.

Medulloblastoma

An 18 yo male with nausea and vomiting.
Here is his Non contrast CT Brain, MRI Brain Axial T1, T2, FLAIR, Diffusion, Post contrast T1w images at the level of posterior fossa with single voxel MR Spectroscopy at TE of 35 ms.

This CT and MRI study of Brain shows:
A well circumscribed ovoid intra ventricular space occupying mass completely occupying and expanding fourth ventricle, leading to mild obstructive hydrocephalus. 

Lesion is solid, hyper dense on CT with spotty calcification at the center.
Signals isointense to cortical gray matter on T1 and FLAIR, slightly hyperintense on T2w images. No cystic component. No marked areas of necrosis. Restricted diffusion on MRI Dw images. Lesion is lobulated, mild heterogeneous enhancement on post contrast T1.
On MR Spectroscopy, no peak of NAA at 2.01ppm, no peak of creatine at 3.02 with long sharp peak of raised choline at 3.2ppm.

Here are MRI Axial T1, T2 and FLAIR images with post contrast T1w images of same patient at the level of lateral ventricles shows multiple discrete enhancing nodules along ependymal lining of lateral ventricles, signal of nodules on MRI are same as that of the posterior fossa mass with same restricted diffusion.

Imaging diagnosis : Medulloblastoma with Csf dissemination. 

Similar post:

Medulloblastoma MR Spectroscopy
Lateral origin medullobastoma


MEDULLOBLASTOMA

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.

Location:
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.