0:00

We are moving from the traumatic and acquired

0:04

abnormalities and vascular abnormalities of

0:07

the globe to the neoplastic category.

0:10

This is a child who had leukocoria on the left side.

0:15

As we scroll through the images,

0:17

we note that this patient's left globe

0:20

shows an area of calcification,

0:23

irregular calcification within the

0:26

posterior segment of the globe.

0:28

The globe appears to be larger in size

0:32

on the left side than the right side.

0:35

This irregular calcification within the globe in a child

0:41

should bring to mind the possible

0:43

diagnosis of retinoblastoma.

0:48

Retinoblastoma is the most common ocular tumor of

0:52

childhood, with 90% presenting before two years of age.

0:58

There are a number of things that one has to be concerned

1:00

about when one makes the diagnosis of retinoblastoma.

1:04

Number one is that the patient may have concurrent

1:13

we see that there does appear to be an abnormal density

1:18

along the posterior aspect of this globe.

1:22

However, it does not join at the point of the optic

1:28

nerve insertion and therefore,

1:30

we are more likely to suggest that

1:32

this represents additional tumor,

1:35

noncalcified tumor of retinoblastoma

1:38

rather than a retinal attachment.

1:41

The next finding that is of concern is the enlargement

1:45

of the optic nerve sheath complex.

1:48

Here we have an abnormally thickened optic nerve sheath

1:54

complex which is emanating from the back of the globe.

1:58

We contrast that with the normal caliber of

2:01

the optic nerve sheath on the right side.

2:05

This most likely represents tumor which has

2:08

infiltrated the optic nerve sheath,

2:10

usually in the subarachnoid space rather

2:13

than the optic nerve itself.

2:15

And therefore, it can extend intracranially along the

2:20

optic nerve sheath to the intracranial contents,

2:23

including the optic chiasm.

2:25

For the evaluation of the intracranial extension

2:28

of a retinoblastoma, MRI is preferred.

2:33

The final thing to consider with regard to retinoblastoma

2:36

is the relatively high rate of bilateral disease which

2:40

occurs in one third of cases and 90% of those who have

2:46

familial retinoblastoma with the gene on the

2:50

chromosome 13q14 portion of that chromosome.

2:56

So we have to be very careful about

2:58

scrolling and making sure that

3:00

there are no abnormalities in the contralateral globe.

3:04

What we would be looking for is any thickening of the

3:07

retina or calcification in the contralateral globe.

3:13

In this case, we think that it looks okay.

3:16

However, we will look at the MRI scan subsequently.