About 2 months ago, my 19 year old son noticed a lump on the back of his head. If you look at the back of his head, the top of the lump is about even with the top of his ears and positioned about equal distance from each ear. It seems to be growing slowly. It is about the size of a ping pong ball. We went to the doctor and he scheduled a CT scan with and without contrast. We just got the results today, but won't see the doc until late next week. I was wondering if anyone could tell me what the results mean and if I should be concerned. The results are: CT examination demonstrates a prominent occipital protuberance measuring approximately 12mm x 20mm. There is no overlying soft tissue mass...everything else is normal. Any input would be greatly appreciated! Thank you in advance!

I should also say that much of my concern comes from me having the decompressive surgery last year for Chiari Malformation.

Such tests take the 'viewing' of more than one expert, especially since your son has had surgery in the not so recent past.
I've waited for many CT's MRI's and PET scans chewing my nails [mentally or actually] for however long it took. Some answers have been good, a couple not so. I'm still here?
I've made a game with myself that good results take longer! Keep that in mind as the days go by and you get that phone call at 6:30pm- that's when most docs tend to call me w/results?
Hoping for YOU and your son that results are not really problems!!! Please let us know? Sending good thoughts.....
's - j