As for the AN, the MRI says it is "an extension of the mass into the right internal auditory canal with mild expansion in the porus acousticas." So, maybe in moved, like a blob oozing into my ear.
From this quote, it seems your AN began in the CPA (cerebello-pontine angle) and then grew laterally (toward the outside of your head) into your internal auditory canal (IAC), which is very common. The IAC is a bony canal that provides passage for your facial, vestibular and hearing nerves, as well as the labyrinthine artery. The CPA is a roughly triangular space defined by the boundaries of the brain stem, the cerebellum, and the inside of the skull. The porus acusticas internus (which the "porus acousticas" in your quote no doubt refers to) is the medial (e.g., inside, or closest to your brain stem) opening of the IAC. So, from your quote, I glean that the medial extent of your IAC was slightly expanded in size by the tumor as it grew on the inside of the IAC. This is par for course with ANs and is no cause for alarm.
A few hours of study will make you quite familiar with reading your MRIs on a basic, amateur level. Here is a quick primer on how to do it:
1. Each "series" has many images contained within. Learn how to open each series in turn and advance one by one through its images. The images with contrast will most clearly show the tumor. Some series won't show the tumor at all, while others will show only one or several images of it. As you advance through the images, write down the image and series numbers for those images you find that most clearly show the tumor. Note the image in each series that shows the tumor at its largest size (in which the image was taken at a "slice" through the widest portion of the tumor).
2. Now note the letter notations on the right, left, top and bottom of each image to determine whether each denotes the top, bottom, left side, right side, back or front of the skull. For example, the notations might say "H" at the top of the image to denote the top of the head and "F" at the bottom to denote the bottom of the skull, toward the feet. They might say "A" (antero) and "P" (posterior) along the left and right borders to denote the front and back of the skull, respectively. Other notations are sometimes used, but you can pretty quickly figure them out.
3. Each image should show a scale in centimeters at the bottom. Take a piece of paper or a post-it note and mark on it the length of 1 or more centimeters (cm). Be aware that the scale (the apparent length of 1 cm) will change if you zoom in or out on the image. Now use your post-it as a yardstick of sorts to measure the span across the tumor from top to bottom, side to side and from front to back. In order to do this, you'll need to figure out which aspect (side view, top view, view from the bottom, view from the back or front of the head) you are looking at the tumor from in the current image. Again, the notations at the top, bottom and sides of each image will give you this orientation. You will need to look at the largest images in different series in order to determine all three measurements (each image will only show you two dimensions and thus yield only two measurements).
It's a bit more complicated than this. For example, measurements are taken at an angle across the widest span of the tumor in each of the three dimensions -- oblique transverse, AP (antero-posterior) and cranio-caudal (or top to bottom) -- to include lobes of the tumor that protrude beyond what would otherwise be a symmetrical shape. The optimal angle of measurement is highly subjective, and each radiologist will potentially come up with a slightly different measurement as a result.
Caution: the smaller the tumor is, the harder it is to tell whether you're looking at the tumor or just the cross-section of a blood vessel, for example (which appears as a tiny dot). In the end, your doctors are the only ones qualified to draw conclusions from reading your MRIs. But you can learn a lot by reading them yourself, and the more you study them, the better you'll get at being able to see for yourself what's going on inside your head.
Best wishes,
TW
