A "Spell" and Family History of Epilepsy
A 44-year-old woman presents because of an episode of loss of consciousness that occurred while she was urinating. She experienced no prodrome, tongue biting, or limb jerking. There is a strong family history of epilepsy. Neurologic examination is unremarkable. MRI of the head is shown in Figure 1.


(Enlarge Image)

MRI of the brain, representative images are shown; arrows denote the pertinent findings.Axial noncontrast T1-weighted (left), T2-weighted (middle), and fluid-attenuated inversion-recovery (right) images are shown.

True or false: The lesion is associated with mass effect.

1. 
   True
   
2. 
   False
   

View the correct answer.

<p>False</p>


True or false: The lesion is associated with edema.

1. 
   True
   
2. 
   False
   

View the correct answer.

<p>False</p>


True or false: The lesion is consistent with acute/subacute infarction.

1. 
   True
   
2. 
   False
   

View the correct answer.

<p>False</p>


True or false: The lesion is consistent with demyelinating disease.

1. 
   True
   
2. 
   False
   

View the correct answer.

<p>False</p>


The lesion is an imaging artifact due to partial volume averaging of a normal structure.

1. 
   True
   
2. 
   False
   

View the correct answer.

<p>False</p>


True or false: The lesion is consistent with cystic infection.

1. 
   True
   
2. 
   False
   

View the correct answer.

<p>False</p>


Additional imaging is shown in Figure 2, including postcontrast and diffusion imaging.


(Enlarge Image)

MRI of the brain, representative images are shown; arrows denote the pertinent findings. Coronal postcontrast T1-weighted (left), axial fluid-attenuated inversion-recovery (middle), and trace diffusion-weighted (right) images are shown.

True or false: The lesion is nonenhancing on the postcontrast study.

1. 
   True
   
2. 
   False
   

View the correct answer.

<p>True</p>


The location of the lesion is best described as:

1. 
   In the putamen
   
2. 
   In the globus pallidus
   
3. 
   Between the putamen and the temporal lobe
   
4. 
   In the posterior commissure
   
5. 
   In the thalamus
   

View the correct answer.

<p>Between the putamen and the temporal lobe</p>


Diffusion-weighted imaging suggests that, in comparison to normal brain tissue, the lesion contains:

1. 
   Low signal, restricted diffusion
   
2. 
   Low signal, fast diffusion
   
3. 
   High signal, restricted diffusion
   
4. 
   High signal, fast diffusion
   
5. 
   A and B
   
6. 
   C and D
   

View the correct answer.

<p>Low signal, fast diffusion</p>


True or false: The appearance of the lesion on the FLAIR image is most consistent with a cyst with associated gliosis.

1. 
   True
   
2. 
   False
   

View the correct answer.

<p>False</p>


The most likely diagnosis is:

1. 
   Enlarged perivascular space
   
2. 
   Epidermoid cyst
   
3. 
   Lacunar stroke
   
4. 
   Dermoid cyst
   
5. 
   Rathke's pouch cyst
   

View the correct answer.

<p>Enlarged perivascular space</p>


The most likely diagnosis is a benign congenital cyst caused by an enlarged perivascular space. The differential diagnosis includes arachnoid or neuroepithelial cysts, which are also benign and congenital in nature.