Lump behind knee in 4 year old?

[lulu40]

I have noticed recently a very odd looking lump behind ds' knee. It is just as if he has muscle is twisted and pokes out in an odd way, completely different from other leg! I cannot for love nor money click on to Ask the Expert so thought I would ask you lot instead - it does not hurt him he nevers moans about it but before rushing round to the Doctors thought I would see if anyone out that has seen anything similar may be his legs have always been slightly different but it has only become obvious to mean very recently.

Could be a gangleon, does it feel quite firm and round? They often appear at lymph node sites, don't know if there is one behind the knee?

Yes it does feel firm and round - just tried to search the web for anything only came up with stuff about them on the wrist and in adults nothing about children - anybody got any ideas?

You can get them as children, I did, and they are classically on the wrist, but can be in armpit, on neck etc. I would take him to your GP just to be sure. If it is a gangleon, they sometimes go away of their own accord, some can be removed by syringe, mine were on my wrist (I had two concurrently) and were removed surgically because they were causing me a great deal of discomfort. The wrist one's were traditionally burst by dropping the family bible on the offending hand!

It sounds like a Baker's cyst rather than a ganglion. These are relatively common in children and are painless, harmless fluid-filled swellings that appear behind the knee. They usually disappear spontaneously and require no treatment. Get your GP to check it for you but there's probably nothing to worry about.

Thanks