0:01

Primary malignancies of the middle

0:02

ear are incredibly uncommon.

0:04

Most of the middle ear malignancies are extensions

0:08

from the external auditory canal,

0:10

skin cancers that grow through the tympanic membrane

0:13

or erode the temporal bone and

0:15

then get into the middle ear.

0:16

So the most common malignancies of the middle

0:18

ear are squamous cell carcinoma,

0:20

basal cell carcinoma and melanoma.

0:23

And these are all skin cancers

0:26

that have variable prognosis.

0:29

When we think about primary middle

0:31

ear malignancies in children,

0:32

we generally think about Rhabdomyosarcomas

0:35

or Lymphomas,

0:37

as I demonstrated on a previous case,

0:39

you can see spread into the middle ear from

0:43

perineural extension from a parotid mask

0:46

going up the 7th cranial nerve.

0:48

So it goes through the stylomastoid frame,

0:51

up the descending portion of the facial nerve,

0:53

or the intramastoid portion of the facial nerve

0:56

into the tympanic portion of the facial nerve,

0:58

where it may present as a cancer.

1:00

There is an unusual lesion called the extraordinary

1:04

canal inverted papilloma, the extra auditory canal.

1:08

Inverted papilloma may grow through the tympanic

1:10

membrane and it, like Sinonasal,

1:14

inverted papillomas can have coexistent squamous

1:18

cell carcinoma in approximately 10% of cases.

1:22

So here we have a patient who shows irregularity

1:27

of the scalp soft tissues.

1:30

You have an erosion here that extends to the surface

1:36

of the squamous portion of the temporal bone.

1:41

And as we look down on the bone windows

1:43

of the temporal bone CT,

1:45

we see this irregular erosion of the mastoid.

1:48

We have a large erosive process in the external

1:52

auditory canal, and it is growing

1:54

into the middle ear cavity.

1:56

This is a squamous cell carcinoma coming from

2:01

the scalp into the external auditory canal,

2:03

through the tympanic membrane,

2:05

and infiltrating also the middle ear cavity.

2:10

Here are two different cases, an adult and a child.

2:13

On the left-hand side,

2:15

you see a massive lesion that was a skin cancer,

2:18

a basal cell carcinoma that was ignored for a long,

2:22

long period of time,

2:23

and it just grew through the entire temporal

2:26

bone into the middle ear cavity.

2:28

The patient actually presented when he

2:30

developed a facial nerve palsy,

2:33

obviously from involvement of the tympanic

2:35

or mastoid portion of the facial nerve.

2:39

You can also see that this is growing into the

2:41

posterior fossa just adjacent to the sigmoid

2:45

sinus transverse sinus junction.

2:47

So this was another cancer in an adult, in a child.

2:51

As I said,

2:51

when you have any erosive process affecting the

2:55

temporal bone growing into the middle ear cavity,

2:58

we usually think about rhabdomyosarcomas or lymphomas. Obviously,

3:00

the rhabdos are a little bit younger in

3:02

presentation than the lymphomas,

3:04

which may also occur in young adults.

3:06

So rhabdomyosarcomas, the average age is five years.

3:09

It may occur secondary to the tensor

3:17

tympani muscle with a rhabdo,

3:18

or it can occur de novo within the temporal bone.

3:22

It is the most common temporal bone location

3:25

along with the mastoid air cells.

3:27

The differential diagnosis for an erosive process

3:31

affecting the temporal bone in a child

3:34

includes Langerhans cell histiocytosis,

3:37

which can again cause an erosion effectively.

3:41

Eosinophilic granuloma can cause an erosion of

3:44

the mastoid portion of the temporal bone.

3:47

And in children with rhabdomyosarcomas, familial,

3:50

this is not a good prognosis. Rhabdo generally

3:54

because it is considered paramedullary.