0:01

When we think about malignant bone lesions,

0:04

far and away, we should be considering metastases.

0:07

And these metastases may be from the most

0:10

common of the primary malignancies in men and

0:13

women, those being lung, breast, melanomas,

0:17

and in men, prostate cancer in particular.

0:21

Prostate cancer is characterized by

0:23

predominantly blastic metastases.

0:26

In addition, another common

0:27

primary bone process is metastases.

0:29

Multiple myeloma is part of the

0:33

plasma cell dyscrasia syndromes.

0:36

Lymphoma may involve the bone as

0:38

well as the extradural tissues.

0:40

In children, we think about the malignancies

0:43

being neuroblastoma and teratoma.

0:46

Here is a patient who has a destructive

0:50

lesion that is affecting both the

0:53

clivus as well as the C1 anterior arch.

0:56

As you can see, it grows into the

0:58

prevertebral soft tissues as well.

1:01

And this was a metastasis from lung cancer.

1:04

Here is a case that I showed previously as an

1:07

unknown case in the intradural extramedullary.

1:12

This is a process which is located in the posterior

1:15

epidural space, infiltrating where the epidural fat is.

1:20

And this was a case of lymphoma.

1:23

This lymphoma causes narrowing of the thecal sac

1:27

below and above the lesion rather than widening it.

1:32

Therefore, we know that it is in the epidural space

1:35

as opposed to the intradural extramedullary space.

1:39

As you can see, the epidural fat is

1:41

effaced at the level of the tumor.

1:44

And this tumor causes compression of the spinal cord.

1:47

Diffusion-weighted scanning is not typically

1:50

performed as a routine for MRI.

1:53

However, if one were to perform such in this case, we

1:57

would expect to see decreased ADC, as is characteristic

2:01

of lymphoma elsewhere in the central nervous system.

2:05

So, reduced apparent diffusion coefficient.

2:08

Here is a patient who has a process

2:11

that very much could have looked like

2:14

a discitis osteomyelitis infection.

2:17

So, you see that there is destruction of the two

2:21

adjacent vertebrae with bright signal intensity

2:23

centrally within the intervertebral disc.

2:26

And it looks as if there is epidural

2:28

compression from the anterior epidural space.

2:32

This ended up being metastatic disease.

2:34

From lung cancer.

2:36

Here is a patient who has a sacral region.

2:40

This is L5, this is S1, this is S

2:44

2, and then we have this process down here.

2:47

What's in our differential diagnosis of sacral region?

2:50

Well, it really depends on whether we're

2:51

dealing with adults or pediatric population.

2:54

In the adult, the most common thing is gonna

2:56

be a chordoma followed by a plasmacytoma.

3:00

And of course, we have metastatic disease.

3:03

In the children, we're dealing with a teratoma,

3:05

most commonly, or metastatic disease

3:08

usually associated with neuroblastoma.

3:11

This was an adult, but it was an adult who had a teratoma.