0:01

Let's categorize BPH,

0:03

or benign prostatic hypertrophy, on MRI.

0:07

There are some relatively basic conventions.

0:10

If you've watched the anatomy vignette,

0:12

you now know that the lateral lobes of the central

0:16

portion of the gland, mostly made up of TZ.

0:20

The transitional zone.

0:21

So I'm gonna, I'm gonna

0:22

circle the transitional zones.

0:24

We're at the midgland level.

0:27

There's a lot of TZ tissue here on both sides.

0:30

Right and left.

0:31

And the TZ, as you know, is divided up

0:33

into an anterior TZ, a TZA, and a TZP.

0:38

But when the TZ really takes over,

0:41

in BPH, this is also known as lateral lobar

0:44

hypertrophy, or lateral lobe hypertrophy.

0:48

Now does that matter?

0:50

It does matter because if you've got

0:53

marked hypertrophy of the central zone

0:56

of the central gland, that'll be in the

0:59

posterosuperior quadrant, back here.

1:03

So, you might have these two

1:04

factors weighing against each other.

1:07

In other words, the anterior portion of the

1:10

gland, or the preurethral portion, may push the

1:14

urethra back if this is selectively hypertrophied.

1:17

Whereas if this is selectively hypertrophied,

1:19

it'll push the urethra down and forward,

1:22

and this will also prolapse into the bladder.

1:26

So this would be central zone hypertrophy,

1:29

this would be TZ or lateral gland hypertrophy.

1:34

Now if you've got the deep tissues

1:36

around the urethra getting big, as they

1:40

may often do, this is known as median

1:44

lobe or median prostatic hypertrophy.

1:48

And this may contribute to pushing the

1:50

central zone further up into the bladder.

1:54

When this gets very polyploid, it can

1:57

even prolapse into the urethra and cause

2:00

urethral obstruction, which is a phenomenon

2:03

described by Aberin many years ago.

2:06

So, we've got lateral lobe hypertrophy,

2:11

central posterosuperior hypertrophy, and then periurethral

2:16

or median lobe hypertrophy, as some very

2:19

basic portions of the gland that may enlarge.

2:24

Now, let's, let's talk about the

2:26

histologic criteria for a moment of BPH.

2:30

In a prior vignette, you've heard what the

2:32

imaging and gross anatomy criteria is, which is

2:36

a gland that is 25 cubic centimeters or bigger.

2:39

But histologically, when the gland gets

2:41

big, it can be from stromal to ventral

2:45

or epithelial hyperplasia.

2:48

And these will have slightly

2:50

different appearances.

2:52

But when you have this hyperplasia, you also get

2:55

a dynamic effect on the urethra, constricting

2:59

urethra from either the back or the front or both.

3:04

When they both equally enlarge, in other words,

3:07

the retrourethral portion of the prostate,

3:11

and the preurethral, or anterior portion of

3:13

the prostate, if they enlarge symmetrically,

3:16

this is referred to as balanced hypertrophy.

3:20

So it's no wonder that you might have

3:22

imbalanced hypertrophy, where the back

3:23

gland is bigger, but not the front,

3:25

or the opposite.

3:27

The front portion of the gland

3:28

is bigger, but not the back.

3:30

And that is one of the bases for low bar

3:34

classification of benign prostatic hypertrophy.

3:39

In another vignette, we'll take a look

3:41

at the low bar classification of BPH.