0:00

This next case is a patient who had left orbital proptosis.

0:05

The patient also had chemosis and epiphora,

0:08

and there was some erythema as well.

0:11

This was a nonpainful process, however.

0:14

As we scroll through the images,

0:16

we see the abnormality in the left orbit.

0:20

Once again,

0:20

we wanted to find in what space the lesion is in,

0:23

and as you can see in this case,

0:25

it has components that are involving the muscle cone,

0:29

as well as the intraconal space.

0:32

The lesion appears to involve the superior

0:36

rectus and lateral rectus muscle with sparing

0:40

of the medial rectus and the

0:42

inferior rectus muscles.

0:44

The lesion also shows heterogeneous signal

0:46

intensity, with some areas that are higher in signal intensity,

0:49

and areas that are lower in signal intensity.

0:53

On the T2-weighted scan, we see that it is separate from the

0:56

optic nerve sheath complex.

1:04

On the post gadolinium-enhanced scan,

1:06

we see that it enhances quite avidly.

1:09

As opposed to the previous case,

1:11

this lesion seems somewhat irregular in its shape

1:17

and has some margins which are less well-defined.

1:25

Nonetheless, this lesion also is a

1:28

venous vascular malformation. How do we know that?

1:32

There are some clues here.

1:34

For example, we see a dark area in the center of the lesion

1:39

on both T2-weighted,

1:40

as well as post-gadolinium-enhanced scans.

1:43

That gives us a hint that there may be

1:45

calcification within the lesion.

1:48

One of the characteristic features of venous

1:51

vascular malformations is phleboliths,

1:55

the presence of phleboliths,

1:56

which are little calcified venous channels.

1:59

This is much easier to see on a CT scan,

2:01

but on an MRI scan,

2:03

the signal void of calcification is a good hint

2:06

for a phlebolith of a venous vascular malformation.

2:10

Just by virtue of overall numbers,

2:13

the venous vascular malformation,

2:15

or hemangioma in the vernacular,

2:19

is the most common of the intraconal lesions

2:22

and may affect also the muscle cone.