Are all AN's inside the canal?

[Rivergirl]

Just an inquiry.... I have been listening to the CD's from this past summer conference and I have heard a few things that I am curious of.  Are all AN's inside the auditory canal? If not what is the difference? Can they be outside? what does impacted mean?  Thanks for any help on this question.

[ppearl214]

Hi Rivergirl

By definition, AN's are on the 8th cranial nerve which runs inside the canal (IAC). Many AN's seek room to grow, thus, many may "peek" outside the end of the IAC to the CP Angle region, towards the brainstem (taking shape somewhat similar to a mushroom.... the "stem" of the mushroom remaining in the  canal while the "mushroom cap" sticking out to the CP Angle region.) 

Hope this helps!
Phyl

[another NY postie]

Hi Rivergirl and welcome to the club!  Mine was impacted and what this meant for my particular case was that the tumor was up against the cochlea with no spinal fluid between cochlea and tumor.  The reality of what this meant when I had surgery last month was that the bugger was slightly stuck on the hair-size artery that runs between the cochlea and the hearing nerve and supplies blood to hearing nerve.  If your MRI report says impacted or you heard the doctors say that (it took my 4th visit to a different neurontolgist for a dr to use that term but after that I asked and everyone seemed to confirm that it was impacted). Also mine was as far back in the IAC as you can go which might have also contributed to their use of the word "impacted" in reference to my AN.
Cheryl

[Esperanza]

Hello, I only have a tiny tail in my IAC with no occlusion and plenty of fluid but unfortunately it stuffed my hearing anyway...      These tumours are a bit like snowflakes I think....

[Rivergirl]

Thanks for the feedback, knowledge is power

[amymeri]

I like the mushroom analogy!  My radiologist and surgeon used the ice cream cone descriptor...most of my tumor was NOT in the IAC.  In fact, so much so that there was much debate meningioma vs AN

[Esperanza]

Hi Amy, one of the specialists I have seen mentioned meningioma too for the same reason - truth willout on removal I suppose.

[Vivian B.]

Hi Rivergirl,

Just a thought. Mine is growing from the CPA and therefore they are calling it a meningioma as it is stuck to the the bone, the mushroom stem per say is growing into the 8th cranial nerve.

Vivian

[Brendalu]

Thank you Phyl, you gave a better description than any of my doctors!! 
Brenda

[HeadCase2]

Hi Rivergirl,
  In the AN literature you'll see the terms Intracanalicular and Extracanalicular, meaning within the IAC canal or outside of it. They can also have both Intracanalicualr and Extracanalicular components.  The Extracanalicular ANs are in the CPA angle, closer to the brain stem.  The location of any particular AN can affect what structures are potentially affected by the tumor as it grows.  And the location can affect treatment plans such as radiation vs. surgery, or which of the three or four surgrical approaches that the doctors may suggest.
Regards,
  Rob

[Rivergirl]

Thanks for the feedback.  It seems the ones in the CPA angle or out of the canal cause less problem as they grow than the ones in the canal, my theory because if they caused if they started causing problems they would have noticedit when the AN were about 1 cm .... just thinking.