0:01

Monomorphic adenomas occur both in the parotid gland.

0:05

as well as in the submandibular gland,

0:07

although less likely in sublingual and minor salivary glands.

0:12

In this case,

0:13

we have a well-defined mass in the left submandibular gland

0:18

which represented a monomorphic adenoma.

0:22

Again, well-defined, sharp borders, no trace of nature to it.

0:26

A benign neoplasm.

0:28

Now, when we speak about benign neoplasms,

0:30

it leads to one of the adages that we say about

0:34

salivary gland neoplasms and that is that benign

0:39

lesions of the parotid gland are never as benign as

0:44

typical benign masses and malignant lesions are never

0:49

as malignant as typical malignant tumors.

0:52

So I'm quoting myself brilliant.

0:56

So what do we mean by this?

0:58

By this, we mean that benign tumors of the parotid gland,

1:03

by that, we're talking about pleomorphic adenomas,

1:06

sometimes behave in an aggressive fashion.

1:09

You heard me speak of the potential risk of seeding of

1:13

the operative bed if you violate the

1:16

capsule of a pleomorphic adenoma.

1:19

That's a real problem because once those seeds are out,

1:23

they spread widely and wildly and it's very

1:27

difficult to ever cure that patient.

1:30

In addition,

1:31

you also heard me speak about the entity of carcinoma

1:34

x pleomorphic adenoma and that is that pleomorphic

1:37

adenomas, although a benign tumor,

1:40

have a potential for malignant spread and when

1:43

they become adenocarcinomas, if you will,

1:47

they tend to have a relatively poor prognosis.

1:50

So that's the first half of the phrase here.

1:55

The second half says malignant lesions are

1:59

never as malignant as typical malignant tumors.

2:02

What do we mean by that?

2:04

In the parotid gland,

2:05

the most common malignancy is mucoepidermoid carcinoma.

2:10

And overwhelmingly these tend to be low-grade tumors

2:15

with very little chance of metastatic spread

2:19

to lymph nodes or elsewhere.

2:21

In fact, the five-year prognosis for low-grade

2:26

mucoepidermoid carcinoma is 95%.

2:30

The five-year prognosis for a pleomorphic adenoma

2:34

where you violate the capsule or you wait

2:37

in 20 years is much lower than 95%.

2:42

So this is the reason why there is this adage that

2:45

benign lesions of the parotid gland are never as benign as

2:48

typical benign masses and malignant lesions are never

2:51

as malignant as typical malignant tumors.

2:54

Do not underestimate the pleomorphic adenoma.

2:57

It can be a problem.

2:59

So here, for example,

3:01

we have a patient who has a pleomorphic adenoma in the

3:07

deep space of the parapharyngeal space,

3:10

as well as extending to,

3:12

at least adjacent to the deep lobe of the parotid gland.

3:17

How do you get this out?

3:19

And first off, it is late in presentation because it's in

3:24

this deep base and it's not palpable.

3:26

It usually is asymptomatic.

3:29

So this issue is that you can have

3:34

seeding of a pleomorphic adenoma.

3:37

So here is one portion of the tumor.

3:39

Here is a second seed of the tumor.

3:42

And here's another seed of the tumor.

3:44

These lesions are going to be very,

3:47

very difficult to remove without potentially

3:50

violating the capsule.