0:00

This is a patient who presented with lateral

0:03

deviation of the right globe.

0:06

As we scroll,

0:08

we see a large process, which is in the extraconal space,

0:12

but more importantly, centered at the lacrimal sac region.

0:18

The normal lacrimal sac on the left side is seen at the

0:25

edge of the orbit and junction with the anterior ethmoid.

0:30

So here would be our normal lacrimal sac.

0:34

As you can see,

0:34

we have a process that is quite large, which is

0:37

infiltrating the extraconal space, as well as extending to

0:42

the nasal soft tissues and deviating the globe laterally.

0:47

This is a very large mass centered

0:49

at the nasal lacrimal sac.

0:53

The benign conditions of the nasal lacrimal sac that

0:56

I would consider would be polyps and fibromas.

1:00

However, this is a relatively aggressive looking abnormality.

1:04

And therefore, we would have to consider

1:07

more likely malignancies.

1:09

Malignancies of the nasal lacrimal sac consist

1:12

of squamous cell carcinoma, melanoma,

1:16

lymphoma and transitional cell carcinoma.

1:20

Because of the soft tissue infiltration over the

1:23

eyelid and extension into the subcutaneous fat,

1:27

malignancy is most likely.

1:29

However, the imaging characteristics of these malignancies,

1:32

all are the same.

1:34

And therefore, we cannot predict what the histology is.

1:37

What I would probably do is just go with the most common,

1:40

which is squamous cell carcinoma.

1:43

What we do want to look for is bony erosion of the medial

1:48

orbital wall common with the ethmoid sinus,

1:52

and to determine whether or not the tumor

1:56

has breached the conal space,

2:00

or extended intraconally.

2:03

We cannot tell the distinction between this

2:06

mass and the medial rectus muscle.

2:09

Let's look at this on coronal imaging.

2:13

This is a coronal reconstruction from the axial

2:16

thin-section images, and what it demonstrates is the

2:20

infiltration of the mass to involve the medial rectus muscle,

2:24

as well as the inferior rectus muscle and

2:27

infiltration as well of the superior oblique muscle.

2:33

The intraconal fat, far anteriorly,

2:35

also appears to be involved.

2:37

Despite the fact that this lesion has

2:39

arisen from the nasal lacrimal sac,

2:43

it likely will require complete orbital exenteration

2:47

because of the involvement of the extraocular

2:49

muscles and the intraconal space.